Coevolution Genes, Culture, and Human Diversity - William H. Durham (introducción).pdf

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COEVOLUTION

Genes, Culture, and Human Diversity

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Stanford Univen.i.ty Presa, Stanfutd, Califomia O 1991 by the Bnard of Tn:astees 'ºl the Ld'lnd, Stanford. Junior Umversity Printed in the :untttil Statea of Americ.a

Otigina1 printing 19p1 La1t figure below indicatea y·w al tbis priBting;

·08 07 06 ó·S 04 03 O, Ol oc

CJP date appeu at th,e end oí che book

lndex 621

Bibliography s 43

Appendixes A. Methods and Supporting Analysis 471 B. First Principies of Genetics s 2 5

8 I Conclusion: Evolution in a Dual lnheritance System 419

7 / Neutrality and Opposition: From Cultural Reason to Cannibalism 361

6 / Enhancement: The Cultural Evolution of lncest Taboos 286

5 / Cultural Mediation: The Evolution of Adult Lactase Absorption 226

4 / The Relationships of Genes and Culture 1 54

3 / Genes and Human Diversity: A Case Study of Sickle-Cell Anemia in West Africa 103

.i / Culture and Human Diversity: A Case Study of Marriage in Tibet 42

1 I Introduction: Genes and Cultute in Evolutionary Perspective 1

CONTENTS

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:i.94

93

SS Sl

SI

The S·ystetn Requhements for Ev:olution Socioeconomic Chara:cteristics aad Maniag:e Pat·terns

o:f tbe Du .. jung and Thongpa Serfs of South·Central Tibet

Maaiage Porms and Po~ital Residenee'i oí the Thonar\d Se:tf• of c·himdro ~1111.'"':g·e G· :v,...,•,e!e ·~ _ . ., _ Y Uut . 1 7-lli!O 1.

South Cen,...., l 'T:· 1·1..-t b N· ·umbe ¡· So- ns m· º"""""·il- - .. : .,, . u1..1.a · ue. 1 'f '· 1 _. · I O _ ·. · -. · . · l"CU.:..-.!i • J Porms and Prequencies of Mamage in a Cross·

Sectiorud Sample oí tbe Poputation of D'ing-ri Valley, Southwestern Ttbet

Ponns and Prequencies of Man-iage Amo:ng Thnngpa Setfs in Chitndro, Central Tibet, and . In Ba:rkhan& Northwestern Nepal

)"\,...,,,., - - ·t -d JlA-~ ' - '1' - ' Am' -- - - T·'•1.. '' t:! .. -t:, ~wnen.e. 1v.uu..1.1age corms r _· ·ong .1• 1v.etan ~ Populations

Explanatí·a11· of Ma· ·n·w- D1'V1us1'ty, i'n Ch1'mdr·o· b y th', e , , , , ' , 1 _ " • ,-, • , • _ ' , , • • , , • , , r , · , " -, ~ ; : ' - ~- . -· . - - - ' - .. ' , . -

Domestic. Rconomy Theory Dilferential Matemi.ty .Amoog B.rothers and

Pre:quency of Polygynandty in a Sample of Nyinba Households

lndicatms of Cenetic and Cultural Divetsiry in Sixty Populations Tetted for Adult Lactase Ahsorption1

¡966-1978, Categorized by Subsistence and Location

G,enealogical Evidenoe fer the Genetie lnher:imnce of Adult Laeeose Ahsotption snd Mal.absolption

Cultural Bvolution of Indo,..!uropean Mythology: Cotre:spondences in the Myth of· Pirst Saetüice

Promb'ition of Sex Bet:ween Member.s of the Nuclear Family in Mnrdock's Sample of Human Populations

TABLES

Table s.s. Table 6.1.

Table 5.1~

TahJ.e 2.5.

Table 2..~.

Table r.r, Table 2..1.

437

42"6· 430

3S5

3S4

346

348

306

Table 8 .. 2. Table 8.3.

Table 6.J.. A Comparlson of Pr:edicte-d and Observed Inbreedíng Depression as Bstimated fl:om Data on Death and Major Ddaets in 'Three Studies of Inbtee.ding m Human Populations

Table 6. 3. A Com.parison oí We:steanarck1s .and Burton's Theoríes e ift4">A ·'i"I ino In·· r<A.t:J·t rr. t.00- ~ 0.11c"'~r¡1."' .. '"'° ·. ·"'~ · .1. a.u. . _.,,

Table 6.4. A Comparison ·Ol Predíenons Irom the Av.ersion and Moral Disappraval Theory and the Optima! Outbreedmg Theory

Table 6.5. Reported Ceasequences of Incest Among Populatiuns in the 1'Si'xty Cultures" Sample

Table 6.6. The Co.rrela.tion Betweea Community Exog.amy and Extent oI Iacest Prohibition in All Popuiations ·of the ''Sixt;r Cultnres" Sample

Table ·6.7. The Cottelation Between Cmnmuni'ty Exogarny and Bxtent o.f lncest Prohibition in Populations with Small Commmrl:ties {<400) in the 11Sixty Culsures" Sample

Table 7. r. R:ights of lGn to Human Flesh OUiing Mortuary Pessrs in Wanitabe Paxisb of tjne South Poxe Pn,pulatio·n

Table 8.1. System Requhements tor Trmsfunnational Change in Geaetic and Cultural Systems

Printipal For~es oí Cultm'al Evolution Hypothesi~ed Mode-s oí Relatianship Berweea Geaes

and Cul:ture Table A.3.1. Subsamples of 157 West Afrlcan Popula:tions Used in

Testing ehe Malaria Hypothesis1 by Language Group and Apicultura! Bmphasis

Tab.le A. s ~I. Siny Human Popula:tions, by Means of Subsísteaee: Theh Lseeese Absotbing Capacity, Ceographie Latitude, and Annual Bxposure to Ultraviolet R.adia:tion

Table ~6.I.. Key Peamres oí the Ineese Tabo.os in the ''Sixty CU!tiires.'~ Sample

···1~b1 xvw. r ~·a . es

1~1 I28 130

116

114

11.2

IOO

87

8,)

Two Models oí Organic Bvolution Organic Bvolution as Illustrated by the Increase in

Cranial Capacity Among Our Hominid Ancestors A Map oí Bthnic Tibet The Símulated Reproductive Suecess oí Thongpa

Pamílíes as, a Function of Time and Ma.rriage Principie

The Símulated Repreducnve Success oí Thongpa Families Who Conduce a One-time-only Parnuon at a Given Iniríal Estate Size

A, Model oí Preservatíon by Preterenee in Cultural Evolution

Reproductive Success as a Punctíon 1of Marriage Configuraríon Aecordíng to the Domestic Econom.y Theory

Sample Distributions oí the Phenotypes aad Genotypes Assocíaeed with Sickle-Cell Anemia in Human Pepulations

The Conceptual Strueture oí Generic Microevolutionary Theory

Schematic Representatíon oí Transfo:rmational Change in Genetic Evolution·: The Case of Síckle-Cell Anemia

Fítness Diagrams Representing Genetic Selection Among the Three Human 1Genotypes, AA, AS, and SS,

The Dístribueíon of Language Groups in West Africa The Major Agricultura} Zones of West Africa The Expected Dístríbutioaal Pattem oí S Allele

Frequencies in a Sample ,of Popularíons Subiect Símuhaneously to· Ceaetlc Selecuon and Gene Plow

FIGU'RES

Fig. 3.5. Fig. 3.6. Fig. 3.7.

Pig. 3.4.

Pig. 3.3,.

Fig. 3.2.

Fig. 3.,I,.

Fig. 2.5.,

Fig. 2.4.

Filg. 2.3.

Pig,, 2. I. Fig. 1.2,.

Fig. 1.1. Fig. I .2.

1.6.0

.247

217·

219 2,2.7

2I4

172 184 186 195 199 20,2,

212.

144

I43

142

r41

139

A Comparisoo o·f Monthly Rainfall Levels and Anopheles Mosquito Counts for Sítes Near Freetown, .Sieira Leone, and Lagos, Nigeria

A Tres-t oí the Malaria Hvporhesís Among' the Kwa-speakers oí West Africa.

Another Test of the Malaria Hypothesis Among the .K wa-speakers of West Africa

A Test of the Malaria Hypotbesis Among the West Atlantic-speakers of West Africa

A. 'Test. of the Malaria .Hypothesi1s Among the Mande· speakers of West Africa

A Test of the Malaria, Hypothesl:s Among the Voltaic- speekers oí West Afríca

The ''G.ene-Culture Transmissíon'' Model of Charles Lumsdea and Edward O. Wilson

Two Categories oí Cultural Evolutionary Procese Tbe Conceptual Structure of Coevolutionary Theory Two Key Meas:ures <>f Pímess in Coevolutionary Theory The Two Principal Modes ,of Cultural Selection Key Ponns oí Cultural Seleeuon A Theorerical Framework for Major Genenc Media·tion. Cross-culrural Simtlarítíes in. the Wa.veleng·th

Boundaries cí Baelc Color 'Ierms Cross-cultural Similari.ties in the Focal Poínte oí Basíc

ColorTerms The Human. Vísual Pathway, Viewed from Below A Theorencal Pramework for Cultural Mediation Th·e Anatom.y of Lactose Absorpnon and Malabscrpdon

in Simplified Cross Section Locations of the Human Populationa Included in the

Analysis of Adult Lactose Absorption The Assocíanon Between Adult Lactose Absorptron and

Dairymg Hístory in Subsample Popula·tions Tae Association Between Fresh Milk Consumption and

Dai:rying History in Subsample Populations Tbe Assocíetíon Between Mílk-use Pattems and

Dairying Hístory in Subsample Populations The Assocíauon Between Cheese Consumption and

Dairymg History in Subsemple Populations The Steep Latitudinal 1Gradient in. Ultraviolet B

Radiation at the Earth's Surf ace Relative Skin Pígmentation oí Human Populatíons in

tb,e Subsample Area Relative Skín Pigmentation of Subsample Populatíons

as a Functíon of Latitude F. ag. 5 .10 .•

Fig. 5. 7.

Fig. s .8.

Fig. s .9.

Fig. 5.3.

fig. s .4.

Fig. s.s. F.ig. S .6.

Fig, 4.9.

Fig. 4.IO. Fig. 5.1. Fig. 5.2.

Fig .. 4.2. Fig. 4.3. Fig. 4.4. Fig .. 4.5. Píg, 4.6. P .. 1g·. 4.7. Flg .. 4.8.

Fig. 3.13.

Pig. 4 .. I ..

Fig. 3. 1·1.

Píg, 3,, I l.

Fig. 3.9.

Fig. 3.8.

xx I Figures

479 453

4. Al'\ ~

446

434

403 404 417

305 33,4 365 369

3,76 39,4

30.1

300

'),. 77

Fíg. 7 .. 6. n· clg~ 7.7. Fig. 8.1.

Fig. ,6 .. 8. Fig. 7.1. Fig. 7.:1. Pig. 7.3.

Fig. 5.11. The Associ:a·tion Between Adult Laceose Absorption ,md Ladtu.de in Subaample Populations

Pig .. s.x~. Subsistence Empila.sis on Dairying in Subsample Populatio.ns, as a. Funcnen of Latitude

Fig. s .. 13. Total Mi1k C.onsu.tnption as a. Funetíen af Látitude A.mong Sui>sample Populadons

Pig,. s. J 4. Tbe Converaíon of Milk to Cheese in Subsample · Populations a_s a Functio.n ·of Latitude

Fig. 6. I. A Theoretiea] Frmtework for Bnhancetnent Through Selectíon by Choice

~ 6 .2. S'Chema.tic Diagram of the Relationship· Beeween "Iacest" and '"Inb.reeding''

Pig,. 6.3. The Genetic Consequenccs of Inbreedíng, as Illestrated by the Mating. ,of First Cou&íns,

Fig_ 6.4* Values of the Coefiicient oí Relationship, r, and oí' Wrlgbt~s Iabreedíng Coefficient, F, as Functions. :of Gene:alogical Relationship

Fig. 6. s. Inc.reaaes in Wright;s Inbreeding Coef6.clent, F, Tluough Conseeutíve Generations of Censanguíneous Mating

Pig. 6.6. Jnhreedi.ng Depressíon, i, as a Punction of the Coeffi.cient ,of Relatiooship, t

Pig .. 6;7. Inereeses ln lnbreeding Depression, i, Through Consecunve ,CeneratioM of Consanguineaus Ma·ting

.A Model of Optima! Outbreedíng A Theoretieal Framework Ior Neutrality A Theoretíeal Framework fo.r Oppositian 'The Locaeíen of the Mrundurueú od Their Neighburs at

the Time of Buropeen Contact n· T.h· x·· ·· · &· . · of N · G· ~ · rlg. 7 .4. . . e _ · uru . ~n .: · . ew umea Pig,., 7.5. The Annual Incídeaee oí Kuru Dearhs in. All

Populations of the Kuru Regi'on Duríng a 21 e ·Year Perlod oí Surveillanee, 19 57 Throngh 19·77

The Estima.ted .A.ge at Deaeh oí .Kuru Vtceíms The Three D,imensions of :Cul,tural Analysts Schematic Rep1esentatlon oí Tl'ansformational Change

iP- Cultural IBvolu tion Flg .. 8~. The Three Compara·tiv:e Modes oí Gene .. Culture

llelattons Fig. 8.3. Trends .in the Batly· Bvolution of Culture and the Brain Píg. 8.4. The Hypothe.si.s of Steep Covarlatio.n and Its

C-onesponding Null H-ypothesis Pig. A.2'.I. Sample .Fertility Punctíoas Used in the Simulation of

Tho,ngpa Family Demography

Figures I ni

A Sample .Mortality Function Used in the Simulatíon. o1 Thongpa Pamily Demography 4.8o

Simpltíled Moleculat Genetica of the Humaa Hemoglobins A and S 48 3

Tbe Oi:ganizatio11 of the Human Globin. Genes on Chromos-omes 16 and I I 4.85

IT'L.e A.--,,,."":l "·•.r>tti,é o.t. M· · ""111 a·*"11·--·11 P~·-cMu·sm at ,. -a0s l..D S'UUI~ ,,.é•-'lf~ ·,t,¡ ':·;i.Q. ··~W · q,,¿~A-: .. ·', · _·- 4.iilOV· :1

Nigeria, in 192,9 488 The Semannc ·Cnding of Color by Native E:ng)isb ..

speakers 493 The Neural Coding oí Color by ehe Lateral Genieulate

Nucleus (LGN} of the M.acaque 494 The Color-Term Foci of 20 Hu.man Lmguages 494 Basic Steps of Pr-otein Syntbesis Within the Cells of a

Complex Organism 528 Genetic Seleetíoa Against R.ecessive HomQZYgote& in a.

Hypothetical. Population 536 Genetic Sdection. Against Both Types of ·Ho.m,DEygotes

in a Hypothetical ,PopuJ,ation s .3, 7 Pig. B.3.

Pig. B.2.

Pig, A .. ~ .. i.

Pi!~ .A,.3 .. 3.

Fig~ A4.1.

Pig~. A.+2.

Fig" A.4,3. Fig. B.I~

Fig. A.3.1.

u:ü I .Pigmes

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COEVOLUTION

Genes, Culture, and Human Diversity •

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The fhst and most important reason concerns the acceleratmg redue- tion of human dilfel'ences in the world today. Seholars oontinue to debate

W-b s·· · d Ge·'·· · · c··:w.c · - and H · · Di'°'' ·· ·it· .J • ,. 1 • ••• ·,,-, ~/.- ,•, ' ·_ , __ 'e .. l ',_~ , . ' \r--, '' .. y .. tuJ y . nes,. . ture, .. . . uman . v:ers y Stil.l Purther·?

· .· ne of the majar íntelleceual ehalleages facing the . -~ .··· behavíoral scíenees today concetns the re)ation·

ship between genes, culture, and human diversity .. The objective is both to develop a. 'body of theory relating geaeeíc and cultural processes to the evolution oí human. differ'C:nees, and to tes·t and retese such theory against the aecumulated data of the behaviaral and social scíenees, Although the challenge is stmilar fur ali aspects of human variation, whether mot .. p.hologieal1 physiologie.al, or behavioral, it. is particuJ.atly great with re- spec.t to human bebavíor, where genes and culture may eaeh have dir:ect and simultaneous influence. There is pressíng need fo·r .a hody of theory that explains differenees ia human behavíor pattems and does so without preju.dgin.g whether the appropriate príncíples are those oí genetics, cul-

l 1 . e b' .. f h tura .ana, yais, 01 some eom · 1nat1on o t.· e ewo, This ,ChaJlenge, o.f course, is ·hardly a new one, Many of the und.erlying

mues ha.ve been recognízed snd studíed íor years as part of the a,ge,.old debate about ''114tut-e versus nureure" and ''instínet versus learn~g~'' In additio.n" many of the Iessoas Ieamed hca:ve already been inoo:qmrated lnto the researeh and teaching of the disciplines most .aiíeeted~ inelu,ding an .. thrapology, biology,. paycholo~ and sociology, It is therefore appropriate to ask tw-0 questíons a~t the start of this eadeavor: { 1) Why study genes, culture, and human div.ersi~ty still fu:rthert and ~l} Why presume that aew :insights can be pined todayl AlthoU¡gb ene could oifet many reasons, particulatly· if one were to sucvey the range oí current opíníon 0:0. the matter, my view is. that t~o stand out in each case.

Culture in Bvolutionary Perspeetive

INTRODU·CTION: Genes ami l/

But can one realistically hope that new solutions will be fo·und ·today fot the age·old issues of .namre versus nurture? Will this not be ju_st an,. other indecisive round in an endless debate? My response to these question.S is optimistic, thanks t.o recent developments in botb antnt"Opology and evolutionary biology. In my opiníon, a. hard :new look at. this subject is not only passible today in light of these advances, it is also logically re~

Why Presume That .New lnsights Can Be Gained Today?

the causes of this "homogenízation," which is especielly acute in the so,.. cial and cultural realm [see, for example, Bodley 19Si.¡ Burger 1987)., but íts consequences are clear: the last 1few hundred years have suceessfully reversed the general trend of prior millennia roward íncreastng human dí- versity, Worse still, the process appears to be self -reínforcíng. The remaín- ing variatioa seems subjecr to ever greater depreciatíon and íntolerance, In . . . . . n1 nh d . .J~- l. my opmion, 1t rs ímportant not o. y to e • anee our un erseanomg 01 the causes of díveraíw beíore tbe ver¡ variance to be explaíned has more seriously dímíníshed, but also to. restore a sense of respecr and tolerance for human diffetences before they are lost forever, One hope I had in start- ing thís proíect was that I might help in some small wa:y to make human diversiry more uaderstandable, less threatening, and more highly valued than it is at present, This seems to me to be a timely and exígent task.

A second problem that gíves urgency to thís topic is the growíng hes- tility· in some quarters berween the bíologíeal scíences on the one hand aad the social seiences on the other. Por yea.rs the sabiect of human social behavíor has been coneested eerritory between them, remíníscent of the uneasy border that sornetímes sepsrates hoseíle tríbes. Sociobiology, call- ing ítselí "the new synthesis," carne rushíng ínto that terrítory in the mid .. r9701s advoearíng the "bíologícization" of the social scíences and Prec<ipitat·ng·· new and eomettmes se ~ill> .. e L ..... der in, cidents. The ..i1eb-~a·te· . . .. l _ n LJ:w -""""'~ .. v-. vv:r . . . .c1 'd4.. . u w . ' . over socícbíologv that ensued (it is díscussed in more detall below] made clear both that ímportanr issues remaíned unresolved in the study of genes and culture in human populatíons, and that sociobiologv; at Ieast in its early form, WM not llkely to resolve them. It appeared to me not so much that sociobiology was wrong {although I have read a number of ar· gum"en·ts to which that claim did apply) as that sociobiology wa.s intrin·

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sically incomplete as a theory for explaining human behavioral diversity. 1 came away .from the early days of the debate thinking tha.t a more en- oompassíng, .sysrematic study of gene-culture relations was n.eeded lest both s:ides retreat and dig themselves into the trenches of the status quo ante bellum. This, too, seemed an urgent task. The question was n.ot whe:ther genes and culture .are related in their influences on human di· veisity~ but llow. Here, then,, were two imponant reasons for pushin.g onwa.rd.

2 / lntioduction

Tbe Emergence o/ Ideatioaal Tbeoxiee 'Of Culture In .authropolo-gy, one oí the more significant of these recent develop-

ments is the emergeace of what Roger M. Keeaing (1974} has called "idea .. tional theoríes" oí culture. These new approaches oííer a more explíeíe and more analytic conceptualizaríon oí culture than has been possible sínee Edward B. Tylor introduced the term to anthropology¡ eallíng it "thar eomplex whole which íneludes knowledge, belíef, arr, morals, cus- tom and any :other capabílítíes and habíts acquíred by man as a member of soeíery." (1871, 1; r.] Por years, anthropologísts have debated about the rsnge of phenomena to be Included within that "eomplex whole" (far re- víews see Kroeber aad Kluckhohn 1952; .M. Harrís 1968; J. Moore 1974). The trend in recent years has been to move away from the amb~ous and cvergeneralized expressíons of Tylor and other early wrieers and to "narrow the coneept of 'culture,''' as Keesíng put ít, "so that it íncludes lesa and reveals more." (1974: 73 .. )

Althcugh there ís certainly no complete agreement on the bese way to aehíeve that goal, ídeatíonal theory has encouraged a new consensus aboue a number of key propertíes of culture .. In. my vteW¡ flve of these properdes are especíally ímportane to the study oí human dtversity and gene-culture relations [specífíc examples oí these propereíes are gíven in Chapeers 2i and 6; see LeVine 1984 for a similar list].

Conceptua: tealit», The Brst and most baste property of culture in the new consensus is Its conceptual realíty: culture consíses of shared íde- arional phenomena [valúes, ideas, belíeís, and the Iíke] in the mínds of human beíngs, 1 lt reíers 'to a body OT "pool" of ínfonnatíon that is bota puhlíc [socially shared] and prescriptíve (in the sense of aeeually or poten- tia.lly guiding behavtor]. A~s tbe anthropologisc Ward Good:enough (1981~. 56) pues íe, the culture of a humaapopulaeton is "a system of standards far beha.vior.11

This property of culture has 'been descrlhed in JnanY ways :by recent autho..rs, but two examples ma:y ·be cited to emphasize the basic polnt. Monis Freillcli has offered this formal conceptualiza,tion.

~~~e. ~~if' .!~~: !~~~~~d:Vf!rs~1!~ ~~g¡: ~::ir~!J:rj~~ 1The conceptual realiry of culture has been aigued pc:rsuuiveJy hy Sir Kad Popper, the

uoted philoao1her ·of scienc~ wh:0 differentiaw die rulity of ideatin.nal phenomen.1 :a$ ÍWotld 311; the cwotcld oE knowledgc, ptinci:-ples, and sta-temeAts in and of themselves. This wo.r:ld, oonsisting oí ''the products .af the human ~nd11 is di!U1lguished lry Popper irom the world of physieal abjcets OI thlng.s ( 1'World t 1') and &om the wntld of subjeetive ~.encu Jike emotional responses Ol'. ·chought processes (''WoJld 2.''l~ Bu\ argues Popper, World 3 ii in no way ''less real'' than 'World.a 1 ·md ~, thc influence o1culture011 human behavioJ proves its reality (:Pop1)« 1972: ch. 4, 1976: 18o H.1 sce aho Eecles 1973}.

quired, The time has come to re ... examine the íníluences of genes and cul- tare on the evolueion of human díversiry,

lnuoductiea: f 3

People who· shate space-me1mbers of the same geogtaphi!c community-share a

U:~~~!1~&i~r:~~u:i~ª:~.i~:! ~~4a!r/~dfd:~~z:;nrm1!1u~=:;: .and developed as a. by-produ.ct of saC'ial interaction). Culture as a me:mber aí the f.a,mily guidance syste.m belonp to the subfamily standMds .... {1977; 90-91}

The same basic message is expressed in different terms in the writings oi :Cliíford Geert:zt a leader o~f ene ide.ati1onal approa~. the se-ealled sy·m· bels .. and·memin¡s v.iew oí cultur:e. One of ·thé more use.ful ways-but far ÍTOm t.he only one-of distinguishin¡ betw~en culture md social syste.m is to see the fom1er asan or.dered system ol

' -~ 4 -.L-I- . l hi'·-l.. • 1 • • .,_f.. ·t d meamng ~ 01 syuWti~, in ter.ms o w ~ soaa . mteracuon YIAe& p1a.ce; m· 1 to see the latter as the pattem of social intet11ictlon itself. On the. oae liattd theze is ·the fmniewatk oí bellefs, expr;essive symhols, and valnes in tenns of which mdi- viduals define their wodd., expresa theiI feelings, and make their judgmentsi on the ·other le-,,r,el thete ís die ongoblg proeess of in:teractive ~baviot, w,hose per-

:sistent ícmn we ca11 social sttuctme. ·Culture is the fahric of meaniug in :tenns of ·whiC:b human being'S interpret their experlence and guide their aetion1 social stro:eture is the form tha:t a1cti.on. takes1. the .aerually exísting ncetw-ork ol social relations..1[1973: I44-45f

An importmt co.rollary of tbis flrst property ean be seen in both pas- sa,ge11 namely that a distinction must be drawn between culture and hu .. man behavior. According to cuu:ent theo:ry, ·cultu1e is properly regarded neither as a subset of behavior {that is, as the specíal ''habita of aceíon" er ''way oí lite'' :oí a peeple] no:-i:· as a superset ol beh:avior (as part ol a. people1s total "''attiíaets, meutifacu,. and sccíoíacts," as in Huxley 1955}. One rea .. son f-cn making this distincti1on is that the ·conceptual p,henom:ena of cul .. ture are only ene guidio:g Ioree o:f severa! that may ínfluenee the nsture and furm of behavior. Gene:&, af conree, oons:titute anothet guiding tol'ce, as do íeatures oi the nat:ural and social environmen:t [see Chapters 3 .and 4J. Giv-en that tw-0 o.r moie of these ,foi-ees may be eonfounded in ,a given action or set af acti.ons, it is mis:leading to say, for instanee, that cuJltute is bebavior transmitted :from one .individual to anodier by leaming and teachíng. Behaviars. may certainly be cultruolly va:ríabls in tbe senae that if the guiding ideas, v.alues, ,or beliefs of a population change1 then a:ssoci .. a:ted beliaviox-s will als.o change. But to inclu.de the behaviois as culture impases a futile nawre/nurture categoriza:tion upan. attrlhut:es that may be .infiuenoed by genes and· culture and environme:nt.~ 1n short, culture should be thought of not as behávior but as part of the infarmation that speciftes its· form.

Social 'trt111smissi:on. A second important property .of culture in the new consensus, although reoogniz.ed for y1ears, is fts distine.tive mecha ..

"The an.thropotagist ErJ:e .A.. Smlth if.hst point'ld this out to me in 1977 (pe$ .. c:omm.) in te5p0n&e to my· paper, 1'-The Adaptiv~ Sipftcanee .of CUltutal BebaviOI" (19:76b}1 wbieh made. thi& mi.stak-e in ita vecy title. Por ad.ditional diac•JBSion of tbis distincstion m.d its ·C.On· sequences &e'e Dumam 198~

4 l lnttoductían

' . nism of transmission: culture is conveyed aocially within or hetween populations" 1/o qualify as cultural, a gjven unit of tnfoJmation must be 'leamed &om oeher individuals {''socially leamed"], not t:ransmitted ge- netically [see Chapter 3J or aequíred {r:om isolated individual expadeoce1

as in uial .. and~tor learning,. In other woidsi as the anthropologis't lloy IYAndra.de h4S well saíd tn his article "The Cultural Part of Cognition!': 11 A goed pat of wha,t any pesson knows is leamed &om othet penple.. The teaching by others can he fmmal 01' infonnaL intended ot unintended., and the leaming can. occur throu,gh observatíen 01 by beíng taught mies. However aeoonlplis,hed, the result ís á. body of lesraíngs, called cuhure, trans.mitted fre>m ene generation to1 the next," (1981: 179.J In. .a sim.ilar veín, tbe ''social lea:millg theory" of the psychologist Albert :Bandur9 em .. phasizes social eonvey-an~, particulatly modeling and '~observational l.eaming,·11 as .fundamental to the aequisition and dissemtna:tion of eul .. mre, Aeoording to Bandur,a, ·11it is difilcu:lt to imagine a social uansmis· sion proc~es& in whieh the lang11age1 Westyles, and institutional praetices of a culture are taught to eaeh new membcr by selecetve relnfo;fcement O'f fortuitous behaviars, wi,thout the beneflt of models who exemplify ·the cultural pattems.'' (1977: I'- . .} The poínt is not simply th:at cultme. is leamed informaüon but that it is leamed in a dis,tinetive sócial way1 thtougb modeling:,

In reeene y~ar~, thís ·pr()perty has been emphasízed as one of ·the key differen-ces between genetic and cultural iaheríeance, In .bis book Tbe ,Bvolution: o/ Cultw:e in Animal8, for· example,. the biologi.st John Bonner goes so far as to ·d,efine culture as ''the transfer of info:ru1ation by behavioral mesas, mos.t particularly by the proees-s o1 teaching ami leaming''1 he. ' it' d' l lth "th . . . 4'..t . " in1i . ' . . · conttasts · •.. .: 1rect-_ y wt. _ .. e transm1s.ston U1t genetie _ :; .. nanat1on passed by the direct inheritance of genes Irom one generanon t:01 the next," ftg8o: 10; for similar delinition,s, see Bajema. 19781Mairuudi19&01 Cavalli·Sfurza and Feldman. 19.81; Plotkin and Odling .. smee 1981; Boyd .md Richerson 198 5···' This definition oí culture duly emphasizea. its ilÚflr·,.

• 1· --..l h '- _.J: ' •at • ' th nrk. l • ma:oon~ · cont.ent w.w t • e ,wct m 1ts soc1 . transm1ss1an .. · · rou5" .· eaxning"" Moreover Bonner, Danilo Mainardi (I 98ol, and othe.ts bave been able: t"O doeument a ftll numhet of examples of. the social traosmission of lJe .. havioml '1·tra.diti.ons11 amon,g nonhuman animalB ('see also Galef 19761 McGrew ami Tutin 197:t\1Munding:er1980). On the other hmd_, a& Mai-

_ __¡.:, '"'""º- 1' ·b n · · t to · ,J......,,tt ·''this :" .....t·· · ll.tl.ed d ..... a~.:·t1·11..-. of· -~~1 D.cuw .\ ~ ;711u; 2.21 . · 1 1;.. ul'S · ·, aww. , · · · · · · . ·. *'º a ~imp .. U:li .• . · · ~0u.u. · v.1c.. · ·. cu1r•• tuxe'',. it i.s also one that explicidy locuaes on ''direet phenotypic: oopying unmediated by arbitmrily meaningful oodes.'' (Boyd and B.icherson 19-85:

ál AJJ, a by-pr:oduct of such social eaDveyance, ooltnra.l informadon is always sha:red tn ia population. &me authots tfox 1iMtano.e¡ Pamoms 19.S x: 15; LeVine 19.84-; 6:8) bave made thi.s a se,amte ~ p.tápvty of culture1 ar:gumg that a ''eomm:uuity of thou¡hr' is neee&sary in ardei íor euJl.ture ·to promo~ regubtiries and putems· am..0,111 mdivtdual behavi:on. Altbough 1 .agJee that d1is is a prapcny ,of wlture, it seems tn me to. lollo-w lrom.., or be derivariw ot die more ba$ic p,ropeny of social uansmi-ssion.

lntroduetioD I s

37 .] lt is t:h.erefoTe a deftnition tbat fails eo i:nelude a thírd property oi eul .. ture, crucial in the emer.ging consensue, a propeny having to do with the natute of the socíallv transmitted in!onnation it&eli.

Symbolic encodi11g. In the vie:w of most anth1opologists today~ eul .. tm.e is h-eavily dependent upan ''symbo:ling,'' cr symbolic, encodin& which Is the bestowing o;f coaventíonal, nonsenaory meaning upon t.bings or aees (as defined1 for example, by White 1.959b). Tluuugb symbolin& pa:rtieularly the fonn of S:ymholing we eall language, the info:rmation content, :accuracy, and effieiency ol social transmission are ali enmmously íncreased over nonsymholic modelin¡ md behavíoral ímitatíon, In :addi~ tíon, inf.ormati:on coaveved symbolically has, by deflnition, socially be- stowed signiftcance. lt does aot mere:ly guide :OJ' in&trnct behavior; it, also makes sense, holds valúe, aad has some "poínr" to those who take pa.rt.

Although recognídon of thís piopetty of culture is not particularly new (Kioeher and Kluekhohn 19sl-, fm instance, tnl!ces ít to the eaxly. 19,4o's)1 . • r., '11 . • h 1 ..... -1 1 !- . e 1t 1s. es-peelWJf promment rn recent aat · ropo ogt~ coneepeuauzancne 01.

euleure. Cl~ifford Gee.rtzr to take a. Ieading example, descríbes culture as 11 -,-· hi··~ •.. t - d· -n··· ' tr fo . -·e • tti' ·d . • tter - o·f:, m eanu· • > -·~· em·bodl·. ' -d- . - syn· - ·llb:oJs "-'''"· e 'O· · "~· "f · an· e,,_._ """ pa - .;n · l! · "'' m· · - · ,. a <A.Ir.,& 0' ·' ~---·: '.. , ' ~· ~.&.&. V __ ,·. ''M ' · · ·-·' ·~ _'-_' · ' 'V·). ·_1• ,, '. " • ·it

' ' - • , .r

system oí inherite.d conceptions expressed in symbolic forms by means of which men commumcaee, perpetuare, and dev-el.op theír knowledge a,hout and attitudes toward, .life.1' (,1973: 89~ see also 1983.) Similarly, David Schnei.der (1976b: 2.02-3} refers to culture as "a system of symbcls snd meanings ... a body of. ~ . postulates, presumptíeas, propositioos, snd perceptíoas about tbe uníverse and man's place. in ít," Roy D'And:mde (1984: II6):, ior .a third 1example1 views culture as ''eonsisting of l1eamed systems of meaning, communicated b,y means of natural langua¡e a.nd other '.symbols.11

In the emerging co,nsensus thls p.rope:rty of culture has special signift~ can"Oe, for two I'.easons. First,. many anthtopo.10,gists agree with Marshall Sahlíns that the 1eladve ''á!ibitruiness of the symbol ts the indicative condition of human culture .. "' f1976b:, 61. .. '} This arbitrariness, of course, greatly enhances ·the itúormati.on density oí social transmi.ssi.on, in that simple symbols. can ,s.tand for complex ooncept&. Por,tbe same reason, so .. ciál tranemission is atso ·mu.ch more e11eative than any system dependent upon tlrings ar acts with inherent sensoxy meaning ticons), or upon .ftxed. vooal ·m behavioral signals·. The cons·ensus also seems t-0 b.e that ''th.e creation of meaning is th.e dis.tinguishmg and oonstituting quality of men."' fSahlim 1976b~ 6.2, I·02;. see also White 1949 .. ) The ugument is b.oth that cultura] infonnation has a oonmtutive fu.nction-it ''eieates realities'' (.rYAndrade 1984.: 93J md ''organizes relati-ons'1 {Sahlins 1976.b: 10.l.)-and that this meaningfulness, m.ak.e:s culture ''ours alone,,' .. an ex .. clusively ''human domain.'' {Holtoway 1969: 407, 3,95.) Although the last wotd is surely .not yet ln on the symhols-a:nd-meanings capabilitie-s oí the great a:pes and other ptim.a.tes {see reviews in Btight I984; Liebennan

_ .11 Cbtles Darwin. was une of tb.e fimt authors to make tbis argument, not:lng diat hmnans differ ,&o.m ·oth~.•imab ''in {~eirl almost in&.Ute:iy lug:et powct of assooiatin¡ togethe:t the most dirVe:tsifled sound& and 1d,eas,'' (19.~2.. f1871}! 111.} FGt DMWin, this "''¡mwer of asso- c.iadng ~{)(.eth.er'' W'a:S o.ne .g-OOd example of the faet that hthe differenc..e in mind betwem mm aad tite highm: anlma1s1 grea:t u it is, cer.tainly is one of degre.e 40d ~ot of kind,'!/' (t9.>2 (1871]: 1'93.j Mol'e .recendy, the biologist Alfied E;mC;rso.n has oJferied a similat' vmw: ''lH~J $Y.mbolic ~nit'4rtion ptodu~ a.lmost a Quslitative difluen~ &om 'mtma~ls. l am sure tbat it was :qumtitati'Ve .as it fevoJ.v~ Jn time.; ~s it i$ now ~ti~} it 18 p.rao- ti-cally qualitative,;'.t ( 195 6: I 5 I.J

scltffom Geenz 11966: 6b·} compares thesyateml~ arpn.iu.tion of e:ulture. to :an~pm, intqiarted but '':tnear.Uy quite: pooily oonue.a.ed.11 Thete is alao wtde&prcad agree¡mmt c1111t- c,e;ming ,the hier.archical natnre ,oJ the infunnatíon in. culture. Nevttthel~, lc-adin¡ rhe· "" .,.,.,.,..; .. ~,. . ..,~rt"óei "'"í'.-t•,""'-... .,'L.,,. )"'.V.f!ls ~--J '-~15~c t.__._,. f tL · ~! · · h' · ,._ .Ji~ll- . .,,..,. v'f~~ 'l!o>VL_,,p.,~~ P4v _,. . .,;, __ ~· v.._,i.C e1-1,,r-uw O. 6J.e w:CfJtre_ y qm~ UJ,QCiJm,w,. thus VietaI Tttmer 1{1977) speib o1 Uroot pandiptS;' ,amt Roy B.apparpnrt (1979¡1 of '1uhimat~ :&IC't:ed potmlateiS.. H

1984),, eur human meaning sys.tems do exhíbit, at the VefY least1 an :fm .. nfiD·· ·· "fte di.• ·t¡L-~~·- ~ o.' seale t'."'.'.'-0m· .· .. heírs " r· ""S.Sl. ·. . uc:J¡\;n-...""' . !J. ~ . u1 . .. . UJ: . .u.o.

Systsmic oigan·izat.ion. The fourth basíe property of cultme co:iwems its structure and or:ganization:: culture takes the ferm of a '':s:yst.em oi knowledge'' withm á populatJon (Ke.esing 19¡4! 89J .. It is, an assemblage tha.t ''tends te forman in.t~rated whole'' marked by a ''strain towaxd con· sistency.'~ (Murdoek 1971: 331-32.) The Iogícal sttucture ís both bierar .. chical. f that is, some of the ínfonnation is more basíc and of bigher order than the rest] and cohe.rent (component belíefs are often linked ·togethet and embedded within the wholet. Similarl:y (although it wiJ1 be not-ed tba:t he inclnded pattems of acdon in his fonnulation as well as of belief]" Clyde .Kluekhohn emphasized tha't ''every culture is a structure-no:t just a haphuud cclleceíoa of all the 1different physically possihle and funrr tionally eífective patterns of belíef and action1 but m íaterdepeadent s;ys- tsm with its fonns segregated and arranged in a manner wbich is fslt u apptUPflate,.íl {IS)S 1: 100,,}

Aithough this :fourth preperty .of culture is widely aecepted by ,anthro~ pologis:ts toda:y, there remains .fairly sereaueus debate about how best to ehamcterize the svseem under study~ Here Keesing {1974: 77.ff.j has re- víewed duee .of the mose recent views·: that cultures are. '"roplltive sys- eems" ~that is,, ''syste.ma o! tnfened ideational cedes lying behind ·the realm ol observable even.t:s1'}t that they are. "strucmral syst:ems'' (in which ''univenal proeesses oí mi.nd. [creare] substantially diverse l!:Ju,t f0-m1ally similar· patte.ms'' of thought sad expression}; and that .they· are ''.symbolic syst.ems'' f,that is, systems of ''shaied symbols and meanings''J .. These tln·ee approaches Iead to quite different views of the eoneene md functions. af culture.1. as D'Andtade (1984: 116} has poiflted out, but they ali aifee tbat cwtur:e is otganized as a more or less integtated sys·tem~ \

Social lristozy. The ftíth important property of culture in the new ecmsensus is its soeiál historJt: the shared ideas, v.alues, and belieís of a culture have all been handed down from prio:r fotms. They simply do not emerge fuJl .. blown as if put lnto place by a single, immutable act of spe·

.lntroduction I 7

Cultm:e as #"Social Her,edity'' Tu · .··.~.· .. · :·. ···.e,. then, the n.ew oonsensus in an·thropology regaxds cuJ·

tures as sys-tem.s of symbnlic.ally enooded oonceptual phenom.ena tbat are 6Alt· .. L..,..,,,.1,. [ l..--.-...:·1y · · ~•w _,,.:.,·S. TZ,. · ·11¡• · h· h.. · L--..- -<h .:L.- -··1.,.,.,....,1 "'*"°'""'J--.4~ h .,,

. ,11~~ . u.~1w-. co11~ .. wuu r .. 'Cl11·c · ~ ownv.- •ª"~on ~"' cw"""" .... ·¡µ¡.,gu.u.lQuo ·a.:~ .a hifto!}ll I .d:i$sgree with bi:s subseqnem ai;gmneat m the aame essay that "time woyks on stan.datds :the wa1 it wom on. mORt otbet: phenmnena.1 lt erodes. ñmetkln and, highlights foim, Cultural ¡standard& have no o'bvious fu11ed.on (they may he inatioul 101 nonmtktnd} t!...,. ........ A th...; ... -.,-~df· m .... ·-"ng 1~ .... ,~ ... 1. .. : .. , __ .. :1.. - .. ,., ... A .. k.. - :hi··.-L o .. ,,, -ó.....Ja-:J ~ ""_.'"' ll'""'•"""' . · ""'" -··~"·"' · . ~·· ... u'l¡ó¡> .. n uti,,...u. w ... ~; ute .---u.-· w W ~ · .... e lll·s.o.uu . ~ :a:..u1""'"

lata wUh other atalldards. We can no more easily demonsuate thc .funooonality of ma· Wlateml ct()$S·C:-OU!bl ma.Wag;e trum w:e can show the utility of Mona Lis:a'S müle. Both e.~~ amples belong te, the &ame ~ aestheties. CUltuml ~d.s1 ate the.n ootwent:ion~ or logical stan:danls; phe:nDme.na given m~g wi'thln a logjcal system.11 (197;: 91.} Aes~ thetie standard& eenaínly do play a l'O'le in cultural (;ban¡e f see Chapter· 7 ), bu.t :1 disagre:e

cial ctea.tion. In a very real sense, ithe conceptual phennmena clw:actetiz- íng a given population a.'t any ene time are the aurviving variante oí' all die co:µce-ptual phenom,ena ever introduced and SQcially transmit·ted. Acoo:rding to Preilich, ínr example, ''1.hile culture is índeed a set of standards1 all standards ate not culture. Cultural standards have a history ~they are 'bis-

• ~--.ll - . .l ..l~-. l 1· '.-onl) d i .. l...J • h .. h to.n\;illly ,ere.atw. ~1gns .-OT · tVl•.16 . a:n · . t 1s t111s a.gmg p:tocess w:. 1c. · gives to le:ulture tts uníque 9uality.¡1 '~977: 9'1 .• )

His aigument has two iínplications of spec.ial importan.e-e for our pur .. :poses.$ Firs:t-1 it suggests that a hiatoJ'y of social OOllveyance is eae key propetty distinguishing cultural roles and r.e.gula·tions fi:.om ''·natural

..... d· . lt h . . 11 . . L.- ' . dri. . fl>4k' . J b . ...t.~- . . 1 · . d .l\ll es, · t at is, our Ui.lStc · , ves L" e: . unger, úlltSt¡ sex, etc ..... an , natural ·environmental} phenomena S'U·Ch U tempereture, humid.ity1 rain· fall, and altitude.11 {p. 90.) Seeond, it emphasizes that histocy has :shape.d aad meíded the seandards of a populaeion that we observe today. ff we seek an understanding of eulture, and of eulture's inSuenee en behavio-r,

l .-.il d to. .1..:- • _, 'h' • t we can scarce y auor · , · ignore t.ius sociw •· is· oey. Deapite the validity of argumente like. Freüich's, this fifth propert-y of

culture has not oftlm been gíven íts due in ethnog;raphy or cultural analysis. Of eourse, pertinent social his:tory may aot be reme-mbered O! re·

· • .1 ..... ..l · de. · · · -•· lthín ·· ·· ¡· · n· ... • h · ~ 1 · .L. · be · · · ~ . ..J COf'UQU a .... qwttQy w1.~ n a popu auan . .out 1t __ as arso onen en tgnorcu or díseredíred 'by ethnographers working in tbe thin time--slice of syn~ -'L~n-n.~" ._.¡0<6'11"'1 ..... ¡L Lackí rt<O ,.,i.. "":.t h:iM,11'\TV .a:~.tL'"'O· ·pi!'i.'lh0,1""-:1 ..t.- ..... "·a: 'f~ too' . . o.f1 ·~ ..... Cll~•:v. J-." •""°"~~~ . ~ ·1Ulil.. :J.,O~u .... ,., .a:~ 1u· 1 u .-'"1#,(',)*ca& Uil'41,ll .v~ _ . '-'"~ .. ~"'

censiseed oJ only the eurrent versio.ns. of values, ideas, and beliets.. This has coutributed to a fals·e tmpressi.on. of timelessness in culture, and so has imped·ed our und,e.rstanding o,t J>attern an.d, proees.s in 1cult\Uál ehange. This umommate trend has shown some si.ps ·Ot revetsing its.elf in what Sherry Ortner (1984: 159) ca,1ls 11anthro:pology's rapprochement with histo:ry .. 11 However, ít zemains to be seen il, in th-e Nt\ll'el ,social hist1o:ry will be treatied less as {in Ortners woT.dsj ·''a chain of extem.al events to which people reaet,.'1 and more as a tl'eadve1 molding inBuenee on the iníonnation en1ntent ,of cultural S'ystems. We will ,r-etum to this point in ·Cha,p1ter 2..

8 I Introduction

soc-ially .and histonQIJly ttms:mitted within snd between populations. As Keesing. (1974)1 has point-ed ene, this view eontrasts markedly with eadier

-......* ... 1· . e -~· d .. b h . ··-1 e: .... emleep""°mattnns 01 c:wture as a apt1ve er ·avmr& systems, 1w m .. sesnee, 01 as the means b·y which human popul:ations maintsin themM selves in local enviranments. The conceptual elements of culture-ideas, values, belieÍ5, and the like-artainly .help to orga,nize and shape human behavi.m:, but they are lo.gically and empirically dis.tinc.t &om the actions themselve-s. As Geertz argued sorne years: ago, "culture is. best seen tlilt as .

. complexes oí eonereee behavior pattems-c-custems, usage:s, tra..diti.ons, h.abit elt19ten-as has, by and large, been the case. up to now¡ bu:t as a set a{ oonuul mecbcanisms-plans,. reeípes, rules, in.stmctions (what com.pumr engineers eall 'programs1}-fo1 the goveming of behavior.1t

(I97·3: 44.J This view of culture has profound implieations for the social scíences

aad their relationship to the natural scíeaees, In the ftrst place, it leads us back to the heart of the problem of relatíng genes snd culture- net aw:ay from it, as has sometímes been clanned, The development 1of ideatiorutl theary in an'thtopology re ... emphasizes that human beings are pcseessed of· two major infomla.tio11 s.ystems, ene genetíc, and one cultm'al. It foroefulJy reminds us that bodJ of ehese systems have the ,potential far transmission or 11inheritmce11 aeross space and time, that both have peo- found eifects on the behavior 1of tbe or;ganism, and that botb are simult,a- neously e~r.e-sident in eaeh and every living human being. The questio~ thenj ol the telationship between these two systems oí .inionna:don cannot be escaped, It is rsísed by the very openlng: premíses of the new idea ... tianal approaches to eulmre,

Se.oond, the emergenee oí an ídeatíenal coneeption o:f culture malees possíble new advaaces in. the study of cultural evolution. Fo1 examp.le1

ideational the-0.ty poínt& ehe way to opetatíonalidng the ·unit or units o1 cultural tran&mission. We can now appreciate that cUlture is handed down through time .and spaee in umts that are conceptua_lt socially oou .. veyed,. s:ymb,olicaHy coded, parts. of a system, and so on fa subject we retum ·to in ,Chapter 4).. In. addi.tion, as we shall see, ideatianal theory points the way to a elearer understandtng ol tbe mech4nimis of oultural chmge.-·the ílet oí Eorees that sbape the social history, succe:satul or un .. suceess~ ol ,such ·conceptual units. l believe it. is no exaggemtion m su,g- gest tbat ideational theory clears the way, far the flrst time in the histo:ry ol .anthropology, ÍO'r a \Jnified general model ·of ettltural evolution.

fu m.y vie~ tbese developments virtually COmpel CUS to IC"'eXiamine the subject of relations between genes and eultUJe. Pirst, the time has come to reconsider the old but sup-etíicial argument that ·''cultural heteditf' is analogous to genetic heredity.11 fBmers.0111965: 56.} It seems to me that with 'the generti •ertion that "1ewmrá'l swidar.ds ha:ve no obvtous l:unetion, 11 ¡wticnkr.ly :if he mea.s aJJ' cultural. standuds. Chapter :2. pt~tS· .a. $triki:ng oounte:r"ample m thi& pan ol Pr:ei]ichts atg;Um-ent.

lntiaduction I 9

advancea in culture theo:ry1 together wi:th the a:dvances ,in ¡enetic thoory deseríbed in the next sectíon, have put us in a pesínon eitbei to give th•t analogy substantial meaaíng fm the mst time-and the:refore to fleeh out what .Al&ed Emet-son calls the "'similar but not Identíeal events, func.- tions, md prceesses of change''-01 to ·drop it ronce aed fer all .. Fot reasons explained in subs·eqriie.nt chaJpters1 .1 am beginning to thínk that there can naw be real analytic value in the metaphor oí culture as eoeíal her.e:dity and in the reanalys1s of the 1'r:elationship'' deseríbed by Geertz:

As the arder af bases in a stt.and oí DNA forms a coded. pro,gram, a set of inst.ruc- tl-01is, OI a :riecipe, for the synthesis of th.e s.tructurally cemplex protclns. which

:shape o~a~~e ~eticlning (se~. App.'. BL so cultuífe r· ~n.erns ~ov.id:e su.ch piro¡t~n;s for ·tite instttuuo:o of the social ead psyeho]o~a1 proe.esses which .sbspe pul)lic 'behaivior. Thougb che S'()tt of infonn{ltion and dw mode of transmí$sion are vastly ·differ:en.t in tb.e tW·O casee, this comparíson <Jt gene and sy,mbo) is more than a str11ine-d aruilogy .... It is aetuall'Y a substa;atial relJttionship. [19·73~ 9'-i see also .E.me.rson 1956, 1965, Swmson r983J

Second, it is, also time to reeonsíder the general subject of relationships between the dyna.mics :ot genedc and cultural ehange, Far example, we need to look clesely agaín ,at the mstter of .inteiaodon berween ehese two information systems. The anthropologist Frank B. Ll~ingsto~, in a now- clsssíc study {1958)1 elucídaeed culture's role in the genetíc evoluttoa of síekle-cell anemia. This study, revíewed in ChapteI 3, suggested a conceptual framewor~. whi1ch might be cslled "ínteraceíonism," te sch.olars in- texested in human evolueíon [see Montagu 196.i, :r9·68a for pertínent ex, .. amples}. In the words of the genetic.is;t Theodosius. Dobzhansky {1962: 18.): '"Human evolu:tion cannor be uaderstood as a purelv biological process, nor can it be adequately deseríbed .as a history of culture. It is the interaction o1.biology aed culture, There exísts a feedback betweea bío- logjca.J and cultural processes."

Although intere.st ln these ''biocultural'' interaetions ·remains hig:h (a point we will retun1 to in Chcapters 4 ami s), s·u.bsequen.t ·decades of re~ search have also ·made it clear that reciprocally causal feedback is bath difficult to :doewnent ·(aithough, there are exceptions, as we shal1 &ee) and apparently quite rare. Jt is therefote uselul to re .. ex.amine the whole.qu~ tion toda·y of whm-tht·t is, und.er what conditions-and how the cbaiiges i11 1one infonnation syst.em induoe or impede changes in the other. Altematively, when interaction is n.ot implied as, for example, when culture changes independently of ,genetic ch.ange--·\ve need to lno·k again at the oomparatfve rates ,a;nd directions of change in the two systems. The point is then to ask when and why do.es cultural c.han,g;C com .. plem.ent, op,pose, or vary indifterently with respect, to gmetie change. ln botb cases, I maint(tin, the emergence of ideational theorles oi culture

.hel.ps both to formula.te tbe que-stions and to ftnd out how they may be answered ..

10 I Int1oduction

Tbe Bmel'genee of G~nftti,c Tb~o·ries of Social Behaviar

In biology, meanwhile, reeent developments have ·CertAinly beea no len impartant to the genera] goal of undemtanding humm diwrsity. Among the mate signiflc.ant of these has been the emerg,ence-indeed the cultural evolution~.-of sociohíology itself .. Althougb, like many others, I am crlti.cal of sociobiological attempts ro explain human behavioral di· vemity a,s the product ·of natural seleetíon acting nn genes, 1 a.m equally impre&sed, by die valua'b)e esrensíens oí Darwínlan theory made in this new 6.eld. Pot ali practica! purposes; these exeensíoes can be traeed b:ack to twin papen by W~ D .. Hamílton {196.4) on ''the genetical evolu.tion. o.f soeial behaviar.'' Hamilwn preposed that the evnlutionarypJooess. of natural selection {deftned below and desenbed ín sorne de:tail in Chapt:er 3) does aot tt~t ali individual organísms as ind;ependent etttities in the een- t:est deacribed as ''survival ol the flttest,'' but permita certaín advaatages to aríse tl'nm ktnship and social relations.

!iamilton'& inslght, generally referred to as the ''p·rinciple of inclusive fitness11 because it redeflnea evoluticrnary fttness to melade tbe reproduc .. tíon of relative:S, Ied to a .rapi:d, resurgeace of inte.rest among biol1ngi&t1 in the analysis. of animal social behavíor. Within a few years, themetical ad- vanees fnllowed on a. number of related topícs: individual versu~s ¡roup S;41't"''-hnn· ·th' .o coses aad b· e;ft·eª"" O'.t. ªO"t:~litv CP"'11pr· "nC-'11 ai··-~i""m eMi<-"'""·1' :~ ·.· .. .Wüu _ · ·~, , 1: ~ ,~ Q\.Q 1@.ü, · . ·-, !W u~ · ll ~, ~9 ,i - .. ,1 : _.~w. ~ ~:_ A·JI ·~u·:~ · ,. ~1.PA~

selectíea, aad pa;r-ent-oHspring confiict. Eaeh coaeributed new ins1ghts to the evo:lutionary b:iology of social beba.vi:or [see, for example, Alexander. and Tínkle 198I 1 D.aly and Wilson, 198 31 Brandon and Bunan 1984). Newly fo-eused emptrical studies txeview,ed in Gtay 1984, 1985) appea¡ed shortly thereafter; ·they laitgely co:nBrmed the utility of the approaeh while sug- gestíng further modiBca.tions. This srea oí study evolved so rapidly i'tsclf that, by 19751 it was recognízed as a whole. new ,subfteld of biology, eom .. manly lmown as ''eociobiology1' {E. Wilson 1975·). Although a full review is beyond. the scope of the pyesent stu,<fYi it witl be useml to iatroduee brlefly a few oí the tettns and prin,ciples central to sociobiology, manyof which tt shares wíth the more general subfield of evolutionary biology {for molie tbmough diseussiollt with examples, see Wittenberget 1981; Barash 1982.; Tlivers 1985).

Genot)'P8 and phenatype~ One of the most basic of all principlea in genetic evolutiona.ry theacy is the distinction ·between '"genotype,11 the SPAhli·ª:e U9fi_..ro """ ....... ~·tu·u' ~ "'"t ""'"" O*""'~n1··~1'1ii <lllY'ld•. ''nhanomps 11 J j.n; ob·s¡A;'l"lJJ' _ ,~'-.t_:1_1. ·· f!1-~1u_"1.t 1~~~, · : .· u.u v.i Ail.__a. · · :&.0Gu-~g~ •~· , , :r .. "-" · . 1 · '1·. - v,. · -t'°. ·:· _, .. ·w ·• ~- able propetties or ,aittribu,tes whethex íthey be moxphologiCaJ, physiological, 01 behavioral. 1 To take a simple example1 human eye ,color is a phe ..

• . 7As di~ssed i!l .Mayr f19B~! 78~!1 .the tc-rms.~.1~MO~'' 1nd '1ph.e1i:otype"' w,e~ cobted

m 19091 along wíth the word gene 1tse:lf, by tbe .Dantsh ,g•ericl&t wmielm Johannsm. Ptom the start; Johannaen: rea.Jized that "a give pñ,en.oiype may be m ~J:ealion f<tt a bJo. •~.-· -- ·¡ ~t'ti [·t·¡,. t ~ .. · ~~"lle orJ>:tt: •v -l "-'· -t· 1b ... o · · d ,.. ~~..1., L.~ 11 t-1 wgia Y..aAA;.,,. ·.na. -1 a ... ~.tU·. l:r'"'·º"ipe,» u!ll . · "J iD. · means . .oe:.s u: nc:eo '"º ue.· · l. ~: u~.,

lntrodtwtian / .11

notypic properey whose "eharacter states" [brown, blue, green, hazel, etc.] vary from individual to índívídual. An ímportant part of that vatiation, but by no means al] of it, comes from variation in the genotvpes of índí- vtdaals, that Is to say, from differe"nces. in the genes respcnsíble for díreet- , us ,, 11 th bi ch . al th . f. th . . . th . . mg ot · .mstructmg · e :io · etme.: s~n · .· .eSls o · · . e .pigmenta .tn .· e ms ( the ínstruetional role of genes is described in more detall in Chapter 3 and App. B).

The dístíncuon beeween genotype aad 1phenotype is particularly ím- portant in. the s.tudy. of human díversíty because of common confusioa in vemacular usage: we are used to speakíng of "inheríted trai1ts'1 as ií phe- notyptc prcperues eould themselves be rransmítted Irom pareara ee chíl- dren, But as the geneeícíst Richard Lewonrín, among others, has empha- sízed, "the genotype eompríses wh.at is ínheríted, thr·ough the sperm and e.m at the momeae of concepnon: a set of .DNA molecules, the geaes, whieh are eoataíned in the nucleus of the fertílized egg, The phenotvpe, on the other hand, is made u.p of all aspects of the organísm .... We do not inherit our phenotvpes, They develop throughout our lifetimes partly as a. conaequence of our genorypes-e-but only parrly," [Lewontín 198i: 18, empha.sis· added, ): In Chapter 3 we will retum to thís d.istinction, and to ... L ' ' if . L tt• L! 'L d h u.Le imponant ·. ·. evasrve re. a o.n.s.1up neeween genotypes an· p.· eaotypes. Por now it shouíd be noted that soeíobiologv regareis social behavíor as simply another aspeet of an ,org-a·niam's phenorype, on a par with its mor· p.hology and physiolo~ and therefore subiece to sorne degree of change under the Influence of genetíe evolutíon.

Gen.etic selecdon~ The procese that Darwin called natural seleceíon, "the preservatíon of favourable varíatíona and the reieetíoa ·OÍ ínjurícue varíaríons" (1964 [18.59]:. 81}, has been redefíned over Che years to its 1CUf .. rene m·. aning in soci ,· b íoloev: the d'fferet• dl \Dprod· .. ,..,..•on o" g·· e· :notyp00 "-.4 , e~ ' .. 1\1 10 . º" . . . l ~ . .n la r\,< YJ...W. . ll ' . . ""'°•' A.m:ong evolutionist.s in other su bílelds, however, natural selection is be-- ginnin,g to take on a latger .and more variable meaning that reflects the arguments of the paleontologist Stephen Jay G,ould :(198oa, 1982a) and oth.ets ·coneerning 1rhigher forros.'' of diHerential repxoductl;ort, such as species selection.• To reduce oonfruslon, let. me simply tefer to che aocio~ biological concept as. ''genetic selection.11 As we will s·ee i:n Chap:ter 3, where the topic is explored in more detail, genetic selection amounts to a gene and genotype sorting procesa: genotypes whose net e.fíe.et on pheno,.. quoted from Ma:yr.j The observable eharaet.eristic:s. o.fa.o individua! result from a complex inteiplay of gen~tie a:nd enrq:e;netic influ~nces, incJuding the :trlophys.ic.al environment an~ as we s.bs;tl see in lateJ chairters, ,cuJtu:re. As 1noted b-y 5tuan4Fox f 1986), the a-11thropt¡>lo§ist Julian sre,w:ard (.1960: 170} was onc of the iir.st autbo1.s to point out that the cult·utálly influ~ enced bwvio.r ·of human ~ is uphenotypical''

8Vrba and Eldredge 1(1984! have ·ex.tended the concept oí natural seleotion to cover the ,,,scning,by dlll·ue-ntiaJ bitth and deatb.11 at any give.n t'focal level" in th.c or:gankation.al hl~ arcb:y of nature:, such as organismsl populatian.s, .specie.s, ar monophyletic taxi~ To l'ilake matters still more oonfusing, not on1y I bu.t other a·uthors llar e.umple, CavalliwSfoma and Feldman 1981: ch~ 11 Boyd and lüeherson 19,85: \:h. 4} now speak o.f '1tho natural scl:ecuon of culr:ural vadation.11

1,i I lauoducuon

types 1esults in a better .. than .. average desígn for survival andlor reproduc .. tion in a given env:ironment will tend to merease in &equency in a popu .. latíon, Sucb. genotypes, and the sp.eciflc genes wíthm them, are s.aid to be 11favored'1 or ''selected for'' by the environme:nt. In this w.ay, genetíc selec .. tion acts as. one major foyce of orgsnio evolutionary ehange,

Reproduct:ive fltnes&. In sociobiollogy1 as in evol:U!tionary hiology. more genetally, an individual or a genotype is censídered '':6.:t'1 if its phe.- notypic char-aeteristiics ate ·''such as to make it likely to oonmbute a mot:e than avers¡e munbey of genes to future geaeratíons .. Pitness may ftbus] be d.e&ed as 'eiíectiv.e deai,gn for reproductíve sutvival.111 (Willia.ms 196.6: 158.) This kind of titness, which can be ealled ''rep.roducd.ve ñtness" to di.stinguish íe &am phy.sical fttness or fitness oí other kínds, is a proba- bilis-tic oon:cept; it itefers to the nu.mber of oifsp.ring that an orp.ni&m may be expeeted to produce-''expected?1 beeause of ita specífie archíeeemre-« . · · · - ª'DV~ponm· ene wh· 09'¿f¡. th · exnected num · her · ·0 • · · 1·y 11a· "' b m a giv~ .. .l ""· · .u.··· .· ... ~. · .,, . . · ~~ • . e "".;.,..r ..... - ~ . . .. · .: · . · is Plmp .· · · ·. p~o. · ª" bilistically weighted avemge of the possib:te valnes .. 11 {Kitcher 1:985: s t;· see also Sober 1984b: 43.J In contrast, an organis.m's. actual reptodu1ctive perfonnance-that is, the total nwnber of surviving ofíspring it happens to produce is conv.entionally ealled its 1rlifetime repreducdve success" or sirnply ''repmductive success" (designat.ed SJ. !v.olutionuy ·theorlsts have found It useful to distinguish two kinds of reproductíve Stness: the 'fD~,.....,r-in;,,n ctneDce'I Of !-.d¡··v;d·· 11,.,,l~ OI of ª·"'"'""Ma:~ geao ·tvn°'S d"'ª-·-d ·_ .... ~,"·~U· ·~ :,:·_ nw:·:.A!_,~-·'il/' -1~_:' ·_-~u.,,~ - __ :~-1~---ir·~·,, ·':~~-,y.

theír expeeted pe,rsooal eontríbutíon of ,offsprlng to the next generatlon1 and the ''inclusive. flmess" ol indiv.iduals or speeiftc genetypes lthe concept Hamilton intmdue~d in 19.64)1 deftned as theit 'total expected. contri- butíon ol genetit 110.ffspring. equivalents1' to the next generation. By a spe- eial formula,.'· ineluaive ·Btness takes in,to aecount n.ot only their personal D·arwinian fitnest. bu't also the eífects of an indilVidual or genotype an tbe Darwinian Btness.es· of hi1$ or her kin (s..ee 'West Ebei-hard 19751 Brandon and Burlan 1984: t8:;,). lloth of the:se measures. are oiten standardiz.ed ,0:n a O·.o to 1.0 se.ale, w·b.ere 1*0 means the gres.test r.elative s.uecess tn passing

. 'l'lft,d ..avio~-.a . . ,...t:;t1'0· e '1l-n;d·' .. 1...o o.;Íar··. L~··ng t 1'12t ,, B~'.,.,, ... e. Oll genes :w~. et ~o-U.O~ conw .. n'7 ilU.11 UJ,.;I .. J: .• .e ~l - e. mos . .Jr,l • .Qy,A

ºt"'n..l--di<1Yot:.r.n the um·'ts· t.-vr t. ....... h kinds - .. l ll't'n.oL>.-0 ......... ,.d".,,.11-lt o· ,l'"'"""'n··g ""r a' 'cUJiu.aI' ·-f¡.~' 1'Wa1 : - _ _ · · · '. ·_ . 1·u.&. UU•: - ~ · · _ · ,- ~- · w· n ··.~~.a.~ o:.&'-1 u·_ :u_ · 'lRiY,.~- O V_·

their genetic e.qui'.fa.lents. Beeaus:e it .adjusts the calculation of fltness to, include the influence of

in:teracti'ln.a among indivi.duals with shared genes; inclusive fitness is generally regatded as a bettel indicator ,of ''effeeti.ve design'1 for passing on

•Ft)llowmg its fo.n:nal qu1111titañve derl:wltiO'.rt, Hamiltan su~d lhi& fwmul.a: as :fol· law-s: 1"Inclnsive :fhaess, may be ima¡in.ed as the petsonal ituess which. an individual a<tttt- ally ·~rases m its. ptadnctlon of a.dult o:ffsprlng as k beco'mes after it hu be.en fhst suipped arui the:n ~ in .a eetUin wq. Jt .is strlp;ped of ali eo:m,pooents wbich can be co»Sid~ GllCd as dne tn dte indivldual's social enmnnwent~ , . , .. This qwiudty is thm a~e:ntH by cef't4in Íla:ctíons a_f tb~ qumtid.es of liarm and bm.efit whi.cb the im!ividual himse!f ames to. ~!~ !tr1esses. of :rus neighlwurs~ Th~ _írf.ctitlns hl qui!&º"º a:te simply_ the ~ti:nu af: re_lAt:ltrllS.hip la measure ofthe prt>pmtitll'l of genes ide~l by .descenc m two Jnd:i:vtdulsl app..topriate W: the neighhours wh<>m h:e a:ffeets,.1' (1964.: 8.I'

Introductio-11 I 13

. .

genes. But it is also somewhat more diíficult to estímate, In principle, an ''ego's'' eHects on the Darwinían fímesses of associates are added to, or subtracted from, ego's own "nonsocíal" [or noninteractíve] fltness, each weighted by the appropnate coefficient of relationsbip (far sample cal- culations see West Eberhard 1975: 6]. According to the folklore of evolutionary bíologj; this procedure was flrst unlized years ago by the Brítísh genetícist J. B. S. Haldane durmg a conversation in an Englísh pub. 11 Asked if he would be prepared, on evolutionary grounds, ever to sacrífice his lile for another, Haldane is supposed to have grabbed a beer mat anda pencil and, after a few quíck calculatíons, to have declared tha t he would willingly lay down his life if he could save more than two brothers, four halí brothers, or eight ftrst cousins." [Kítcher 198 5: 79.) Haldane's cal- culations, anticipatíng the concept of inclusive fitness, follow from the coefficíent of relationship, which equals o.s for brothers (that is, on average, half oí their genes are identical by descent], 0.25 ÍóI half brothers, and 0.12 5 Ior fust couslns.

Adaptatum. Another itnportant concept in socíobíologv; one whose generality and significance are hotly debated today, is that of "adapta- rion," the appropríateness 01 "fit" of an organism's Iorm and function to prevaíling environmental conditions. In sociobíology, "an adaptation can be considered as any characterísuc ol an organism that increases its fitness. '' [Barash 1982: 24; far additional defínínon and discussion see Pit- tendrigh 1958; Williams 1966; Stern 1970; Holland 1975; Brandon r978,; Lewontin i979b, r984)'.1º

The subject has been coneroversíal, in part because of terminological confusión. To take one example, Stephen Gould and Blisabeth Vrba have argued in an influential paper that a fearure should be considered an adap- tarion If and only if it both "promores fimess" and "was buílt by {geneticl selection for the functíon it now períorms." (1982: 5, emphasis added, see also Brandon 198 s.) They suggest the term "exaptauon" Ior those "useful structures ... that are flt for their current role [hut] were not designed Ior it (by genetic selection]." This argument, however, contrasta strikingly with one made just three years earlier by Gould and Lewontin, who noted that adaptations can be shaped by a number of different processes, not simply by genetic selection.

First, we have what physiologísts call ''adaptatíon'': the phenotypic plasticity that permits organisms to mold thei.r form to prevailing circumstances du_ring on- toge:ny .... Physio}ogical adaptations are not heritable, though the capacity to d.evelop, them presumably is. Secondly, we have a ''beritable'' form of non-

1ºThe concept of adaptation ís also central to a large portion of anthropologica.l theory, panicularly the suhflcld oJ ecological antbropology. For reviews of iu mea:ning and uses in this context, see Alland and McCay 1973¡ Alland 1975; Bennett 1976; Burnham 1973; Ki1ch 1980, Little 19831 Borgerh.off Mulde.r 1987a; and ~ro and Borgerboff Muldex 1987. On maladaptation in human social systems, see Rappaport 1977; Wcis1 1980 .. FOT a critical ass~asment, see Bargatzky r984.

14 J Intioduction

''These. distinctians are US:eful fot tbeote.dul aad .conceptllal c1ar1t-y. As I have ar:gued earlier f¡Dutham r976a, 19;76bl, actual hwances oí ~human adapta.tion may s.anletimes oon~ iound two, ot more m-eobanimns· a.nd categnfies,.

Darwhúan adaptatlon itt humans {4.nd, in rudimentary ways, in a kw othét ad~ vaii,ced social ape,cies): cultuml adaphltio:n fwitb heritability imposed by Jeam~ ingj~ .•. Pinally, we haw adapwio,n arlsing :from the conventional Darwinian me:cbanísm of selecden upen genetic. v:arlarion. The mu.a eKistmce e/ a gnad Pt betwoo'll o,rgmlism and snv.ironme.nt is i11$1tffidoot: evidmc-e for inferrm, tlJe¡ ac.- tlon of (genwc] 1slection. [1979: 59~-93,, e:mph.asis add.edll

To their Iíst one eould add a level correspondíng to behaviotal adapta .. tion [the mmneot-to,.moment behavíoral adjustments oí organisms)1 ene might also distinguish the class of reversible physiological changes (like an ínerease in red-blood eell densicy} frem irreeersíble devclopmen.tal ad .. ~ptations [see discussíon in Maynard Smith 1966: eh, 1). 'Ihus organisms. in genersl, and ehe human organism in pardcular, hsve a full inventory of ada.ptive respease mechanisms, eaeh with d.ifferent propereíes and ti.me coustants :(aee Slobodkin 191681 Slobodkin md Rapoport 19741 Bonner I980: 6:i-64J.

Thís discrepancy in the definition of ada.ptatio:n can. be resolved r.eadily enDugh if one uses the temt "organíc adaptatíon" (after Willism.s t966: 96} for features that promete fttn;ess an.d were buílt by genetíc selecnoa for theit eurrene role; the terms ''phy:s:iologicaJ;'' and ''de:velopmental'' a.daptatio.n for featmu of phenatypic plasticity that are noe socially tmll& .. mitted; and "euleural adaptation'' for Ieatures that are similarly func .. ríonsl iin terms of fltness but were shaped by sociocultural processes for eottelated benefles .. 11 These dis:tinetions also help: to reduce wha.t Gould and Lewontin (1979: 593} call the "confused tbinking'' in human soeíc- biolo11 that arises f:rom a failure to difíerentiate geaeeíc &om ·cultural medes oí adaiptation. E.ven so, the debate over adaptatíoa is cenaín to con .. tínue for some time.

Genotypic seIP,sbness. Wherie genetic selection has been the major foree in the evolntíoa of the behavi.ot of a speeies, individuala are ex ... pected to behave in wa.ys tha,t maxímíze the p:rop:agation of thcir specifie genes. In other words, they are expeeted to· behave .in ·''a genotypicaD:v aelfish fashion,'1. enpging in acts of apparent self·sacriBc-e only when, in fact,. the act! enhance theiI individual inclusive fltness {see 1\ .. Aleander 1·974). It sb.auld be emphasized that the concept ,of genotypic selfishoess appli.es only where the ,evo]ution of phenotypes has been guided by· the ditierential reproducdon of genotypes, as opposed to, othet evolu·tionary forces like migtation ot drtft fas discussed in Chaptet 3}, ot to differen.tial reproducdan. at othet JJevels {see Wilson 1·983,).

Phenorypi:c altruism. Given the baselin.e prediction of ,g:ellO'typic seli- i.&hne.ss, one of the eentral pro;blems oí sooiobiology is ·to) explain the evolution oí the sharln¡, carln,g, and saerlll·ce tb.at are founíl in various fonns

lntroduction l 1 s

am:011g. social anímals. There are now quite a mnaber ,of sociobiological the.oriea for the evolutíon of such ''pheno:typic altruis,m,'' that is, .fo1 the e:volution. of hehaviors thait appear altmistic bue that, from a g.enetic per- speetíve, are actually s:elilsh. Let me simply meatíon three of the more ímpenam ones, íPirst, there is Hamiliton's argumene {1964) that geaetic selection can. favur the evolution of altruistic beha:viors by lndi.viduals for the benefit of clese kin4 The requirements are two.. First, there must be ,genetic dilfetences. berween the altruísts.-toward~kin and nonaltruists.. Second, this behaviot mUSít yield the higbest net inilusi've ntnes.s ·01¡ in other words, rhe Btness value oi egols e:Hect en relatives must do more than comp:ens-ate for aoy attendant deerease in ego's, own Darwíníaa fit· ness, Where these conditions are met, phenotypic altruísm is said to evelve by the special fom~ "'1 genetie ;Seleetion ealled ''kin selecdon" ,flor díscussíon and elaboratíen, see West Ebethard 19·;5).

A second Important a:rgument ís that of ,R.obert Trívers, who has showed that genetic selootion caa favor the evolution of temporaty' re- ptoductive sa.crlfloe by sa organísm row·a1d nonrelaeíves, so long as ehere is an eventual nee ''retum: be:neftt.''' 10ne hnma:u being sav:iJi,g another, who la not elosely relaeed aad is about to dfown, ís an ínstanee of altruísm, Assume that the chance of the drowning man

·dying is one~half ií no ene leap_s in to &ave him11 but ·that the chance tbat bis poten- tíal rescaer ·wtll dtown. il he leaps in to save bim is m.uch smallet, say, oae in twenty~ As-sume that the drawning man always drowns when his reseuer does and th.at he is ,always saved when the rescue:r survives the reseue atte01Jpt .••. Were this 411, isola.ted ·event, it is elear ~in terms of fitness} ibat the eescner sbo.uld not botber to save the dtowning tnan. But il the dn>:.wning man recip'to.cates at some futme time, and u the survival chmces. are tben exaetiy revarsed, it will have been to the beneftt of each participan:t to have ris:k,ed his life far the other .•.. If we assume th.at the ·entire population, is ooone:r or later exposed to the same rlsk of ·dtownil)& tke two individw.ils who risk tbeir lives to save ca,eh :othez wiI1 he- .s .. Jeae,d ave1 those who ·tace drowning on the,ir own. [1971: 36,. emphasis. lldded)

The implieatian is that l1fesavi11g b~h.avtor, an exam.ple of what socio .. biologists ca.ll ''redprocall ,altruism111 would evolve by the differential re- produe:tion oí geno.types..

By itself, tbe lagic of the argument seems soli1d and .generaliza.ble, a.nd there is now su,pporting evidence f.r:om field stu,dies oí a_nimal behavlor f'();X reciproca! alttuism of othet kinds frevi1ewe,d in Trivers 1985: eh. t5), Mor'CovtrI, the logic h~as ptove-d useful far, identlfying k:ey variables and for

.makin¡ certa,in priedietions. Par exa.mple,, T.rívers {1971) notes that the ad .. vantage unde:r genetie sele-ctlon. of sueh reciproci·ty depends npon 1tbe fit~ ne,.SS ben.eñt of the alttuis:tic, act to the recipient being greatet than its ñt- ness oos-t to the perfomier, and upon. the probability that the bencftt will' 1one da:y be re.ciptoaite<l Opportuniity, fot the evolution by genetic selec· tion oí reciproca! altmimn is thus expect,ed to vary positively with species·" longevity and ínversely with th,eir dispetsal x·ates,. Where th,e preced- i~g illus.tration is, on shaky poiiods, however:, is. with its assumption that

16 / Int1oduction

recíproeaeed lifesaving in human pepulatíons evolves by genedc selection, We will return to this and related problema in the next seetion.

Finally, a number of socíobíolegists have poínted out that the mecha· nísm Darwín called "sexual selectíon" (1964 (1859]:. 87ff.J can also cause the genetie evolutíon of seemingly altruistíc phenotypes, '~What I cal) Sexual Seleetien," Darwin wrote, "dependa, not on a struggle for exís- tenee, but on a struggle between males for f access to} the females, the re· snlt is fu.suallyJ not death to the unsuccessful comperítor, but few or no offsprin.g~'' [p, ·88.) Through thís mechanism, the mating preferences of adule females can cause tbe dilferiential reproduction of genorypes to favor a greater degree oí self-sacrífice on the part of males than would otherwíse be the case. In addi.tion, as Darwin was flrst to poínt out, sexual selection can cause size dimorphism and other sex-speeíflc bebavíor pataeras, as when the males of a. specíes are larger, more ornare, or better equípped Ior figh.ting than are the Iemales [see, for example, Dawkins 19·76: 1·53.ff.).

Tae Sociob;iology Deaase An Interese tn thc human a·pplications of aocíobiologícal prlncíples and

coneepts had heen evident all along, but tbeir successful emplovment elsewhere in the animal kingdom added momeatum to the development of an exphcít human socíobíology [see, for example, R. Alexander 11974, .E. Wilson 1975: ch. '1'71 Chagnon and Irons 1979). Tbis, in turn, touehed olf the debate mentioned sbove, with many and far-reaching consequenees for the S·tu1dy oí human behavíoral dívessíty [see Caplan 1978.; Barlow and Silverberg JI980J Kírcher 1985}.

At the .heart of the matter were two relaeed conceptual issues. Issue 1 stemmed from an emergent .ambiguity in the deflnition and conceptual- iz,aitlon of secíobiology i tselí, On the one hsnd, socíobrclogy was gíven bread deflnítíon at Its formal inception, when the biologist Bdward 10·. Wilson descríbed itas "the s.ystematic study of the biological basis of ali social behavíor," f r975: 4.) The breadth of this deftnition came from the words ''hiological basi.s'': although Wi.lson himself sometimes, equated this exp.r:ess1on wlth ''reference to evolutíonary explanations in the true :genetic sense'' (as when, in the same context, he con.tras:ted socfobiology and soeiolog:y), ·that ·was not a n.ecessary c-0nnotation. As, Wtlson later emphasized, sociobiology was inte:nded. to be ''a scienti6.c discipline, nota

1particula:r theory conceming the genetic basis of human (or nonhuman] social behavior.'' (1982: xii.t On the other hand, socio·biology was q,uickly given a. narrow deílnítion both by its proponents, eager to use genetics ,and Darwinian theory in .examples of a '''biological basis1' to social behavio,r f,see, f'Or example, Lockard 198.0~ .. Ba:rash 1977·,)1 and by its critics 1(see, for example, Lewontin et al 1,98.4; Montagu 1980}.'ll In thls conception, so-

lllTbis narrower definition emel!gcd. vja three pafhways.: (:s:) through :formal de.cla:tations by propon:ent:s, sucb as D.avid. Barash'i& statement that ',Jsocioblology is tbc applicotlon of

teuoducuon I I 7

ev·ofuti.ona1y biology to the social behavior oí animals" 11977: 21 emphasiB added)¡ i2) th1ough attempts by ·pro,ponents to operationalize sociobio[ogy ín specitlc hypotheses an.d research reporta [see Locbrd et al. x.976 {ora elassíc ·e.arly examp)e1 fnr other CX.fmlples, see Lewon.tin, &'Ose, and Kamín 1984: ch. 9)1 a.nd {3} tfu,ough ehe .a:rgument"S of critics who em.~ phJs·ized ·that natural selec·tion .is, in sociobiological theo.ry, a genet.ic .mechanism (set;, .for example., Durham. 1.9J6b, 197.S, 1979h1 Gould 1978, 19.Sob> 19ll3.a1, Gould :and. Lewontin l.97'9J Lewontín 1979b)'.

1' SociobtoJogy's proponents and cri·tlc:s all agy;ee th.a:r the prncess .of generic selection can cause dte evolution oí .a pherrior:yplc p.roperty U attd. only i1 .there is f~some corrilation. be- twecn the genot·ype and the phenotype in question.11 (Barash 19'82: 29.} As fu1ther evidence of ambigutt.y m, the definition of sociobiology, Barash calls this thc "central pt·inciplc of sociabiol(lgy'' w:itbín 47 pages of Wil:son's (1982} .statement, quoted above, that sociobiology is "nota: particular .t:heo.ry concerning th.e gwctlc basis of human. behaviox.''

'" Pe.riso11ally, f was initially sym,pathetic to tbe term "soeiobiology" beca ose of it.s. fo.rmal broad definlt<ion by W'ilson. That deílnition seemed to .me to invite the expansion of models of evolu.tionary cb.an.gc "to accommodate the retention -0f ·traits whether tbased on chemic:al irnstroctions genetlcally inhel'ited at co.nc,eption, or ·on accum.u.lated 'wisdom' passed ,along someume$ con,tinuously and :from m.any 1p.arents'" ID·urham 1976111: 3A6l, a.11d so 1 used. the term. in. i~s broad sense :ín my ,fl.rst p.ape:t Oll the relatlonsbip of genes and c-ulture. W1thin 'ª matter oí mo.nths, howeverl it ~am~ clear that most readers .and wrlters, associated "1ocio- bi0Jogy" wirh the nanow aeflrution, tn pan .because there was no oomplementary cultural theory o.f the type that 1 was arguing tor.

cíobíology meant a genetíc explanation of social behavior. Observed díf- ferences in behavior were ateríbuted to diff.er.ences in genetíc composi- tion, to the acríon oí genetic selectíon, or to some other procese oí gene tic differe.ntiatio.n.·•jJ Trívers's exarnple of lífesavíng is a case in point.

Issue 2 eoncemed the conceptuahzation of culture in the socio- bíological analysis of human behavior, Although many of the fleldls proponents have regarded culture as importanr ro the study of human behav- íor, few have treared it as an Ideatíonal system capable of evoluríonary change in íts own right .. Instead, as we will examine in more detall ín Chapter 4., culture has been vtewed as the set of speci6c behavíors or "traits" of a populatton [an approach that inevitably confounds the effects of genes and ideational phenomena] oras some sort of reflecnve "self-expression" of the genes. It has thus been treated as an aspect of phenorype, much as physiology and morphoíogy are. Culture has generally not been treated as a coparucipant in evolutíonary change in human populerions, far· the most part, evolutíon has: been deflned as a genetic procesa

The ímplicanons of lssue 2 have been profound. First, in the absence o.f an ídeatronal conceptualízation oí culmre, and without a theory of cultural evolutionary change, socíobíologícal explanaricns oí human so- cia) behavior have reinforeed the narrow defínition of socíobiology [see Durham 1979b1), despite rhe e.ffons. of Wilso'°' Roger Masters (198.2}, anda few other scholars to reíníorce the hroad one. 1" Indeed, the sociobíology Iíteranue of the 197o's and early I98o's is peppered with faitly sophomonc behavíoral analyses suggesríng causadon 'by genetíc selectíon where the data imply,. at bese, stmple correlarion. Coasíder, for example, ehe following passage from David Barash's tufluentíal l977 textbook, .Sociobiology and Bebaviot.

18 I Introductiot:

Cive.n the peculiar hiology oí Homo sapiens, males prt)bably mmmue theu fit ..

tions, so long as ·~ did not requíre further investn1enL Women mq al.so · · ·· ., a been selectBd .for an interest ín oopulation~ eutside the patr .. tJond but~ beeause of their greater involvement in the consequeaees of sueh aetivity [i.~, piegnan_cyL wnmen sho11ld he more .fossy than m.en. Men áre predicted to ieel more thi:eat~ ened by tbe aetivities of theit wmnen than women shnuld feel as a result of sexual dallimce hy· their m_en .••. m eHect" I mn sugg~t~g a potsnti,al biological basi~ fot ths daub.le HtatJ.dard. u {1.977: i91, emphois added}

The argument víews berh behavioral tendeneíes snd the ''donbte stan .. dard11 as produ.e.ts of the differential r.eproduetion. of genotypes. But note that the double standard Is a fttti~g-if momlly obj'ectionabJe-illusttaK tíon .o;f the ideational phenomena of culture, ene that exhibits all five oí the basíc propettÍCS aiscussed esrlier, including social .history. In the ab- senee of my. semblaeceof ideational theo~ argumen,ts .like Batash1s imply that the double standard and other cultural phenomena are the direct e,xpres~ion,s oí genetic ''whi!spering;s within11 (Barash ¡9,79}~ In essence, they o:ier a presum:ptive geaeeíc histo.ry in reply to the eall lor an aetwal social history.

In my opinian, lt is ar.gnmentB of t:his type that explain why the nanow cnncep-tion oí socíobiology has beeome the ,generally aecepted one in both the pu,bli.c and the academíc v.iew toda~ particularly in tl1e social scí- eaees, Sociobiology is now widely regarded as "the geaenc viewpoint'' and is inextricably associated with ·the idea of 11genetic.U1 transmitted social strategies'' by both its p:rilponents fas by ·we:negrat 19,84 and W'md. xg.84,, to take receae examples) and its erities (as. by Lewontín, Rose, and Kamin 1984). In an eifort to reduce oonlusion md semantíc conttoversy, 1 feel oompelled to use the narroW¡ consensual definitíon, of sociobiology in these pages'" ~

150f eo~ Ba:r,a.Sh is not a!Qne in thi$ argwnmt; for revtow md disous.sirm. s:ec Hrdy and Willi.tmS\ 1983. Por other exam:ples of the utge to eq,uate coaelati.on wlth cauutioll, see BataSh 011. '~a po.ssible .evolutifil\ary basis foy human racial prejudicei1 (r.1977: 311}1 o.n the causes of hwn.m male--male ·eompeti.tion fp. 3oij_, and on '"wh}• it is usullly dte mathe:r's part!nts who hdp out m<>st wh,cll [ai new baby ardves;" ,{p. 31».) 14Th1 be s.we, meic QOlltinu.es m ''evohnion md rd:nem.ent o,f sod.ohio:logit1l th~ry'' ·lsee Caplao tf83-i fñt appllcations see Diclreniatm :x9851. Boqerho.ff Muld.er rg87bL and thCJe are exccptions ,to the oonsensnal vlew. Boyd md llichmon, fo1 instante, provide an ÍllStrocdvc exeeption,. dd.ttit\g humm sodobiology as :the vlew that the p~ of cnl- tmal evolutioo 11will \lsually e~nee wmetic ihne$$.11 {Boyd md ruehmo11 t·98;s: r3.J Two groblema mhe:-re in this ddlnlti~ firsi, pxOOOMe$ ~f culwul change t:bu ''~ geam-0 fitacss'' ¡mmto•, by deftnition; thc, adapuation of human1 popuila:tiom tD thm environtnGlts,. By impliu:tion, die iabel usoeiobJnlory11 would then apply to. any suh~eld. o~ .mq¡~ tha.t Vif'WS Cfdtute as promoting adap:tation, including the mueh. olde.r 11~ogi"11¡1) subft~d of ~ .-.nthtopology {~, fw: exarn,ple, Orlove 198ojc. Seoond, if we use the dic®ñary' mailing ·tlf 11U&Ualllyll (ºOR the average"}; Boyd aM 1Ucherson'a OWll work becumes kúly s,ooiohíologie.al 'by dteir own deíiniticm, &in" they admit dtat tite variou:s m:ecltmtsma ril cultural ohange in their themy ·that &ometimes. permit maladaptatian {sec Chaptet 4 of this book:l are p,.ro'bably 'iadaptive when a.v~ged. o-ve1 many chara,c'ters anti many s.ucie.tles,h (:B:oyd md llieherson 198s: 26&.J

lntto-ductian I 19

The concerns nf this book can thereío.re be seen .as a dkect outgrowth ol two parall.e,l sets o1 advances, each m example oí cultural evolution in • 'gb ~L.~ l.•.l • ,.\-.L.~ • f ·1· • th 1ts own n , .t: w.c ,emergente O.i lU:eattoniu uwortes o,: cu ture .m an ' 1-0,. polo·gy, and the emergence of the01ies fm the ,geneti.c evolution oi sociaJ beha:riot in hiology. Both adv.ances make possible new forms of rap~ prochement between bi.ologv and the social S'Ciences¡. each nf tbein1 al~ .. L..- ..,¡,, .. diff . it ff t d b . ,l, • th 'hi' t . uwu~ in , : : _ e11ent ways, 1nv · es n.ew e ot :s towar · 11~gmg · ._ e , • . s on· cal gap betw:ee-n these nelds. In additio11t ·each ·points dhectly to the need for further theoret:ical and empirical research on two key 5ub1ects: ·the pattems .and pt0"1"esse8 ot cultaral ev.olutio~, and the nature oi relation· ships between cultural dynamics and gmetic evolution ..

Toward an Evolutionary Anthropology

Seeond, in the ahsence of an adequate conceptualízation of culture, the implications oí sociobiology have clearly been anathema to the social ecí ... enees. T.hls has certainly beea tbe case in anthropology where, for years1

culture has beea treaeed as a supplementary system of evolutionary change [see Peters 1982). Whíle that tteatment has oíten 'be-en. vague ar·(as I sball tey to show} enoneously stage-.like, snd w.hile no: speciflc theory of :eultu:r.al evolution has ever gaíned .general acceptance, the point re1:1wns that ma.ny social scientists hsve long taken fer grsnted ·that cultural &y&- teme do evolve and that their evolutíen has had profolmd. effects oa human behav,ior. T!Le focus af theit attention, unlike the sod.obiologi.sts/, has been en the social' processes ·that guíde the "descent w:ith modifi.ea- tíen" of cultures as they are handed down.from ancestral populations,. To ,social scientists-1 there has been ao eeason to presume that cultural difkr- enees .have a geneeíe histo:ry~

Not sur¡rrisingly,. reectíons on both sides of the íssue were oíten hos- ti'l JI.-_¿,\._ l ~ . d •L ick .,,.._ ·-,..; • • b' t., • t . e. tu.1~u·Opo O~ltS an otners were qW m cnneaze iSOClO 1·owglS CS io:r 11 draggin_g genes int.o tbe analysis11 of human social behavíors and fnr ofierlng .a genetie just~fication for certaín socíal ills. Sociobiolo.gi,sts, in tum, críncízed aathropologists fm ignorlng DarwtniAn theoty and for assuming that genes pl.ay little or no role in behavíoral dlverslty (cm these íssues see Caplan 1978·; Ruse 19·79; Fetz:er I985J,. There was, once agai.n, p-recious little míddle ground, Clearlyt socíobiology in tes narrow fono. wa-s not tbe "'new synthesist' tha.t had been p-romised, at least. with respect to human behavíor, But, at the same time, it was also ma:kiag ímpressíee gains in tbe expl:anation of ehe social behaviot oí othet specíee, pareícu- larly through the use ·Of the inclusive ñtaess concept. The ques.tion fe·

·· d e ···1].l th id f · 1 ·· ª· he ínfull 1· ed ·d maine # . · ou.w . .e 1 ea o inc: us1ve a.tness ·. gat, ·. y empi.oy . outst e he .. .t 'b··¡ d ld'b d . t narrow purvtew 01 socto 10 'O&Y, a:n: c-0u . lt .. e teame· ·. up m some

meaningful ·way with an id&i·tional approach to cultu1e? It seemed to me tha.t it oould~

20 I lnttoduction

The Concept of Bvolutian Beeause the concepe of evelunon, for reasons we w:lll tum to shortly¡

,ha& had a Iess tha:n illu.strlo-us career in the social scienees, it will be useíul to begin with a b:rief díseussíen of just what it means and implíes today [lnr an iostghtful history of the oonc.ept, see Bowler 198,91 en the word ''evolution'' itself, see Cameíro 1972 and Could 1977: ch, 3) .. From the start it will be uaeful to bear in mind three things that evo1lution1

pqpular us,age to tlie oontrary, is .not: progtess o·r improvem.ent (it is simply cumulative and transmissi.ble ch~e);: genetic selection or 'tDar-- 'w:in's theory'' (these are instead ideas about the mechanisms of evolution in a\ spedftc context, namely, orgruúc evolution):; 01 an exclusive pmperty·

,of· 8enetic systems [.many· things. can and do evolve). The 'be.st ooneise deflnition oi evolution remains CharleB Darwi.nts fa .. ,

mous one,·lilier frmn On tbe Oligtn af Species (1964 [1859]): ''descent with modifl,eation.11 The suecess of this detini,tion through tbe years-it,., seU an impiessive cul·tural evolutio:nary phenomenon· ·can be attrlbuted ·to three of its lmplleations. Pirst, t.he phtase has general applicability: i·t implies. that many 1thing$ .can. evolve,, not j1ust the speeies· of Darwm's.

i-ri~-1 l s d' h .hr . I!. d . , wi..:L. A ....... _ ... º"'~·ª eoncern. ' eeon ,, t· e ·p ase 1mpu.es envattan ·. u.1 w.w~,e or ·"modiftcation'' hut does .not presuppose any parti.cular fonn or process of ehange. .lt therdme encompass:es a theoretically u:niimited set of possihle proees.se.s, not simply Daiwin1s own empha,SÍs upoo natuml aelecticm. Third, tb1e pbrase seems. to suggest neatly the full set of con:eepmal 1ele- me.nts that ·we now reoognize as '''syst"Cm requirements'' for evolution in

Happily¡. such eíforts are now be.ginning to appear in the literature. 'f v... • r=: 11' Sf ..l M'.. F ldm I C";,..J· ,,.,J• Tr' . . • d J.AAt,gt \...arVa :l· ·. nrza an"' ··.·· .. ar:cus e _ans .· wtmw .. ansm1ss1on tm" · Bvolution ( 1981 J, Charles Lum&den aad Edwatd 10. Wilso»'s Genes, Miad, Olld Culture, {1981 Jl and Robert Boyd and PeteT Riehetson's Culture and the BvolutioaaTy Ptooes.s (1985)1 all reviewed in Chapter 4, paniculatly deserse ante. This gxowiag fleld of ínquir:y. bas been ealled by many names; includln¡ '1rioeultural anthropo.logy'1 (Bennett, Osbome, and Mil- Ier 197.SJ Katz 198!21Onner1983}, ''cultural Darwínísm" (Richerson anti Boyd 1984), .ami. the ''new sooiabiology1·1 [Caplan 1983}, eaca oí which I lil-d - 1n1e ínaccur ·tA n..'11' peihjr,...,M..,.,'° Fo·· th ~ sake oí "'11""""'*t'V and No:.. su· f!ttt'1ild"t mir ··~ 1111tv.""' ._ -a """ 'v~ · ,...,,;_ ~"·"· _ · if ·.,:lo;~·- · •. ~~~'"'' ~· · "u· ·--•""° a parallel 'With ·tbe position 10Í evolutíonary bioJogy withiu the biologic_al

•. d .L. l . h W • .. i...: th· ..l.!-. ' t.!- .. seieaees an·- \ile newer evo uuoruuy psye. O·· ._gy w1Ulin ·· ·at Ul.:liClpn.ue [see, for,exam:ple, Cosmidee and Tooby 1987; Tooby and ,Cosmides 1.989), let me simply call thís subfleld 1"e,volutianary anthropology:'' Although the te1m has beea used beíote (rot example, in Bliebtreu 1969), there is today,. mr the :fhst: time, a snbstantíal thecrencal literatur~ wi·lh this

.focus, aad a gro.wing a:mount of new case stu,dy material. The book beiore you r~ptesents an attempt to summarize aad extend our ·understandíng ·OÍ this su_bject area,

lnttoduct:ion l ~ 1

any given syste1n [see Table t~IJ.11 It implies some clsss o! thíngs that de- scend and are modi6ed. (Re.quimmeiu t)1 some meehanism al oontinuity by which these tbings "desecad" aad per:sist {Req:uitement 3); and some procesa of modification (R.equuement 4)1 whi~ in turn, assumes some source of novelty or varlatioo ·(Reqwrement 21J within the elass of ohjoots. Requirement s" seueces of tsoladon or dis.continui.ty, permits the accu- mulatíon of differe:nees in Ineípíent su·hsystems ami. thue eventual diver· siflcation~ Arguably~ te is the only requírement not represeated in the phrase (although Darwín was clearly aware ,of its evoJu.tionary sig¡rift· canee; see, for example, 1964 [1859]: ro4-5).

To Improve upen Darwin's deflni.tion today, er at least to be more explicit, one has to· be considerably more technícal and long .. winded .. Lewontin, for instance,, has argued that an ''evolutiona:ry pel'apeeti,ve'' or sn interest in "evclutíonary dynamlos'1 is equívaleae to beíng intere:s.t,ed ''in. the change of state oí some uníverse in time''; ·whether· tha1t universe eensísts of soeíetíes, languages, specíes, geologíeal features, or stars, there is a '''formal xepre$enta·tion1' of the evo.lut1o.nary proeess that is ccmmcn to all { 197 4: 6}. The f-0mial representstíon i.n questíon depicts evolution as the. sequeneíal transformation o1 a gíven system. lf we lee S,. denote the staee of the system at time t, and let T:repres.ent the preeesses of transfor .. mation, then

. T T T . • .. . S., 00 • • • • · • "' .S1 · · s~ ·· .: ~ , -· S, •• ~

In this way, sequentíal transiormation gives nse to both co.ntinuít~y and cumuladve ·change. Oí cousse, the process Ol' precesses behiad that tran&,. fomia·tion may themsclves vary through time, md. tbns all ehe T1s in ehe scb.ema need not be id.entica] or even consistently weighted .. Ne\re-rthe .. Leas, th.e result will alwa:ys be a proeess oí "descenr with m-odification·'11 in ·the sehema above, S., has descended with modiftcation ftom Sa, which ·i..11 tum :has descended from s~ and so on.

Acoording ·to Lewon.tin, two hasic ehallenges con&ont any evolut'ioa~ ary thoory! how to repr,esent .S, in arder to speciíy tbe changes (if anyJ be-

111\ble 1.1 is an elabo:ra.tton on Campbell's f196s: ~71 "'th1~e huí(; rrequ.Uem.ents'' 101 a Darwinia.n model oí evolu.tion1 namely; "'the ooeuue11c:e oi variations,,0 ªcomiste.nt sele<r tio:n cdteria., 11 and "'a :mecrumfsm l'ar th.e p~rvation1 duplicatiml, o.r pYopagatton. oi posl~ thely seleeted ·variants..11 Otin¡ Camphel], Naa:oll md W.irs.b\g {z976: 189-9()'.)! give imr amular iequiremeut&, addiag as uumb~ one "a. poptllatian oí entines campedng fut sumvaJ..tt

TAB.t~ r.r Tbe System Re~ui.rements fm Bvolution

l . Untts oí Transioi&sic.m 1. Scui'ces .qf Variatiofl

.3. Mecbamsms o.f Tr,ansmiss.ion. 4. Prooesses of TultSionnadon S. Solll'CeS of ko:lation

lil I lntroduetion

Key Questions ia the Study o/ Evolution Gi.ven the ''system requirements11 listed in Ta.ble 1 .. 11 it is no surp1ise

that th.e most important fand often the most hotly debated} questions asked albu:ut the e-•-0lutio:n oi a sys:tem are also Bve in numbe.r .. These questinns have particular p11ominence in evolutlonary biology today {as can be seen.1 fm example, in Sober I 984a), but they wi.ll also be key ques. .. tio:n:s in the emetitence of an evolutionary anthtopology.

Wbat are tbe be&t u!li.ts far· de-scribin:g the .systeml The :study 1of evo'"' lution in any system requires id·en.tifying the units whose cbanges pto· vide the best desetiptlon of sequential transfonnation in the system. In ·the case oí living system&,, one can. be mo11e speciflc: we need to know what a:rc the fundamental units of repUeation, ot' wh.at are the thing:S that replicate differentially tluougb gpaee and. time. Mnre speetiically, in the case of orpnic evolution, ·the ehallenge is to identify the objeets-for ex .. ample., g.enotypes, .individuals,. ot species-that vary in B.tness (Bmndon, and Btidan l9·84J. In the case ol cultural evolution (to be taken up in tawr chaptersL the ''units que.s,tion'' will be pa.rallel: In what units are the ideational phenomena of culture differentially transml·tted·?

tween ·times 1 and 2;, and how, to cbaraceeríze T. This coaeeptual render- mg, he belíeves, can be generaliaed to a wid.e rancge of syB.tems, inclu~g

1·ntt11---1 s: · *"'·''""'- - ·-t~'i"O ;;.n..d th· ·e others · iA_ ...... ..:1 to bove e· ut '' :.: 11 g.eo-1 .... ~wu .. wa:a.u.1.eB, Si cu.&11 on . ' .. n .· re1'41-CU . auuv1 • · .· ·.'. OI,galliC. or 't'genetic'' evnlution I-emains· the prototype example, Again we may take Darwin's "descent ·with modincation'' as a useful descript:ion of this kind of evolutíen,

Implicit in Darwin's theol"'f¡ however, is one pr'Operty of evolu;tion in. liviq systems that is ignored or at Ieast ·downplayed in L-ewontin~s

h th- . . ofuni thr gh dtim i ' h ·, ._,,.·:,~I')•,·:···.· .· ,-,·,··, .. ,. ,·,· ·,' ,, ,l, ,· ~, ,··, '• ·.-, :·.·,·., -·.·~ '.· •I,- ··~•·, ,·~ se emaA .. ·. e transmtss1on , . ts .. ·. ou. . sp.ace m . . e .s, in sac sys tems; a,ccomplished. by serial repl:ication,. ·tha:t is to say, by the actual re- crea·tion of unit& rather than. by theit simple enduranee (the former is. arguably what Darwin meant bf "descenr" in the first. place}. This mecha·

.• t; • ..J.- • th ib·1· e -1 al wsm 01 tr-ansmtsztwDi m turn, ereates · . e poss · ·11ty OJ a spe"n1. p:roeess of transiomtatia.n within system.s of: repli.·cating entitíes: e,volutioo can oeeur as a censequeaee of the :relative suceess or failure of units at rep .. lieation. This pmpert·y of evolution in living systems has beea duly emphasized by the bio}Qgist Richard Dawldns (I·9?·6,, 1982.a), whohas. argned that ge,nes are, in faet, tbe wotld's original :replicato,rs.

As man.y authors, including Dawkims, bave poíneed out, evoluden as aequential transfonn:auon. in a system oí replicating ent1.ties is not lim .. íeed to genetic systems. Cultures, teo, Bt this. deB.nttio.n. Indeed, as we shall see in Iaeer chaptem, tbe syst.ems of shared Ideatíonal phenomena in human. populations are, in many ways, model systems for thi,s pa:rtieular kínd oí evolutinnary. ·transfar1na tion. Acco.rding ro this deftnition oí terms, then, cultures s,urely do evol ve~

lnttodnc.tion f .i3

Wba.t are the sousce« of variauoo« Given a sueeessful answer to the ftrst queman, it becemes impo.rtant 'to ask about the origins and. va.riation of units. By what proeess or prooesse¡ ·is variation ints:oduce-d into ·the sys- eem of units undergolng sequentíal changel In the case of orgti,nic evolu- tíon, two different kin'ds of proeesses have been identified as ''pri.mary¡1'

or initial, eourees o,f varlation: mutation, or the spontaneous introduction f • . • th' l J . .! . d • di' '..L .• -1· -l· ' • ..:L ~ o var1auon at. · .. e eve , oi: pnotypes an: m· · . viuua s1 anu specuu,on, ~

fonmtion o;f variable, nonint:e1bmedin¡ desc.endant populadene. Second- a'!"V senrces ...,t, ·va"'•a•;•fift would ínclnde TnÍtr'Ta•:.fift and the Iª0·h~~U'li!-·g nf ...,.,1 a_'·,~,· ~'-''7 U..l ·~· - Li .. · .U.\.U-:& '-TVUl-. ~~ ·· · \.... ~~ UV.;u a..a~ · .'ljj' ,_,g .. UU:ü.11, : U,-·-

varlallt$ known as recombíneuoa, Fr:om the arguments of Gould! (198,,a, t982b) snd oehers, i.t would seem ·that both prlmaryp:ro:cesses may be re- quíred for a full answer to the '1origins questíon" in orgaaíc evolutioo.. With res;pect to cultural evolutinn, .app:roximate equivalents wauld be innovation, or the introduction of new coneepts into: a population [see Bamett r953,), and dive.rsiftcation or ''cul,tural specísrion," fas in Dieaer 198o: ~7), the f.ormation oí new and distinct eultural systems fx1ml old. enes,

What are t:he mecbanisms of transmiasion' Given variatJon,. what then govems the transmissi.on oí units thtough spaee and time and eíther maintains or erodes variabillty? In the case ,of organic evoluti.on., the an ... swer to thís "transmíesíon questíon" has long be-en supplie.d through reí- ereaee to Grego1 Mendel's laws of inhetitance 1{see,, fOI' example, Stern and Sherwood. 19661Olby1985), th.at is, through reíer"Cnce to the regularlties of gene transmiss:ion caused by actual biological reproductcion. Today, bow:eve.t, there is ín~easing evide:n.ee íor irregu,larities or "'violatinns'' of Mendel's laws [see Cr-0w 19179}" snd íor non8Mendelian processes of gene duplieation and t.ransmi.ssion wi·thin and berween s:-pecles (see Temm and Engels 19841 Syvanen ¡ 984}. Ironically, these fbldinp now force us to reoonsider wh.a.t were earlier points of differen:ee between ge.neti,c and cultural ttansmiSS:ion, such as the assenion of the antbropologist .Alfred boeber that whereas otganic evolution ''really does nothin¡ but diverge,.''

l,d. b . . d 11 ' ·ffff•o -~ 1v~o..o 'U· t '•'t .~1vnr.~nA.o n:rt.' ;~·n4st~·o·O<AC1 •n~ ' niil-' a C""D·- •!i>Mil...... , .. '"'""'et'-/ . !.l. •\;lt¡ ,.-·.LIW'-~"'1 cu..:... ~~. 'li.lu¡c. "f:lc'iilf".J llAl~J Q:Q . , .Y .

sequence oí inter:po;pulational diffusion and botrowing. t 1. 9'6 3: ·6'8 ). Now there woutd seem to be posaibilities for coaleseenee and assimilation in the tranemission pr.ooesses ,ol both systems.

Waat aie. the main cawes of trans.f<l.rmationl It was in response to this qu·estlon that Da.rwin so clearly set bis. views apart trom those of

,other ea,tly theorists, including Lamarek .and Wallaee, and left bis g;reatest ma.tk on modern biology. ln additio·n to deftning and describing the pro·

h ..... 11'100 ·-.1 -• • D · id :a~ ... 1 d ... _1.·.a d · cess e ~ .· , naturai s~ection, .. .arwm ·. entil.ieu an · qwuiu.e ·. it as 11·the main bu.t not exclusive 'me.ans ot modLRcati.on,.'' (196.4 (.1859): 6.,) Altkougb he reeogni.zed the p.roce·ss of preserwtion by .re:produetive a·d~ vanta,ge ,as ''by far the p1edominan·t l'ower'' in the ev.olution OÍ 1otpnic fotms f p. 43 J, Darwin a.voided ''Wallace's, .fatal flaw11 of hype.rselectionLsm ('Gould, 198 s ), that is, of attributin,g each and every phenotypic ~lttrlbute of

'-4 I lntxoductias:

Lt A numbei oí recent authors,, m-any oi them writing m the name ol sooiohiology, ha,ve fallen int-o the same trap 38 Wallai~e, p:rovokir>;g Cnuht and Lewondn {t979¡ also Lewontin ;r::979'b) intt> wdtiQg ~'á crltiq;tte of :the adaptatianis:t programme." It has pt~ all too t:asy for modem evolntio..nists to forge.r. or ignore Oarwin{s arpment abou.t the 11main bn:t no.t exeJuatv~ meusr' of or;pnic evolution. Thus one 1finds suclt statements. in ·the li.teraw1:c u Daly md Wil&On~s f&om ·tkcir teubook.J: ''N~al weetion is tite mechauism that canses evoludoa'' {t·ffS3.! s, e.Dlpkams added.J

"'In hia th~ozy, Darwm libned the itye;ry slowt imumittmt a.c.tíon of natural selention'' ·to ''What goology· tells us of dte ra.te md manneT at which the ·i.Qba~ af .this wo:tld have e:hanged .. 11 Howevet slow the ptoeess of selection,. he c-0uld He ''no· limit to tbe amount .of ehmge, t-0 me ~uty and. inBnltJ,? oomplaicy al the ~ptaliODS beiween all :en;:· · . 'e be·

~ - " , - - . ~ - - -. - • . . - ' . ' ' • ' ft. - .. ) - ' . ' .• ' ' 1' t. 1 l ·-·. - • ' - . ' '"' mgs, eme witb. mother ami with the1r physical oonditions. af lif<;: wh11c.h, may be .· .~.ed .111 the lcng ooum m dm.e by ruuure~ pow.er oí sel~iün .. '_, :{1964f18s~l: 109.} iven U ''D.arwín wu. not :emmly a gradwllist,'' as authors sncb as Anllur {1984: 1.1:8·-tt) have, olaimed, it ~ cleat tbat he felt oo.mpe:lled to justify a gradual Yiew ·ol change.

a gi·ven nrganism (or, indeed, of all organisms) to an evolutionary deriva- non by natuml seleetíon, ''

Darwta also ireoogniz.ed that natural selecríon commonly aets th.rough . individual-levet dilfe:renoes. Wllatever th,e reasons for prent .. ehild differ .. enees, he aqu.e4 it was "the sready aceumuletíon, thtougb. natur:al selee- . - • ·1 h ,J:..a -·-'- b . .n · ·' ¿f. • .J.: ·a 1 .. i..__ [ 1· tion, Oi sue uuiel'ences, wíien '' ene¡1.Cltl;. to we mwv1·. ua I uüat ¡ave

dse to all th1e more impottant modiftcation.s eí serueture," (19·64 [1859): 170, emphasis added.] But if natural selectlon generally favored ''sli¡ht vuiatio.ns, eaeh gpad far the individual possessor" (p. 459), theie were direct implica.tiom íor the psttem oí change in organic evolu.tioD¡ or what are now eslled the te:mp:o and mod:eof transfonnation. Here, too, Oa_rwin was expliei.t: ''That natural selection will. always aet w:ith extieme sJ,ow ..

1 full d . ··1 ( 8 t 11A al el ., l 1 b ness . · · y a m1t.: p. 10 • · ·. s natura s _·.eetion aces so e"f y ac.eumu .. lating sligh:t, sueeesstve, favorable variations, it can produce no grea.t or suddea modi&cation1 It can act only by very shert and slow steps. Henee the canon of ,-Natura non facit saltum' [naeure does not make Ieaps]." (p. ,471.)

In shott, Darwin was the ihs·t to admit that hís predomínant Powe-r - - d t haJ tod t I . , L - .. ·- . . -- - , ' '11 -t - ... -· • -- • ....• - .t .- . . - - .. - - • mus-t be slow an.· gradual m. operanon p. 317}, a v1ew t- t .1s o ay

ealled ·11phyletic gmduallsm,'' snd he was the tlrst to defend this position with refeyence to the. geelogieal record, '9 Hís proposaJ. was apdy sum"" marlz:ed in a schematic ren.ditian of the '':great Tree oí Lile,'' ·a p.ortio:n of which is r«irawn in Fig. 1.11 panel A. The figure shows clearly that,;, to Darwin,. oT.gmic evoJ.ut.ion proceeds tbrou¡h the gradual accumulation ol sli,:ght vm.ations. Specíatíon occurs ~the branching points of the tree], but species farmatio.n dees not it&elf cause rigniHcant ditectional trenda ..

In reeent years, this vfew of life has been conttasred with on,e intl'O'- duced by Nile-s Bldredg.e ami Stepben Gould in 11971. Called the theory of ''punctuated equilibria,"1 ft maintain.s ''speaking of mod.e, that aigni&:ant. evotutionary change arises in coinciden.ce with :ev:ents of brmching spe- eia.tion.1 and no·t ·primarily. ·tbrough the in toto tmnslormation of lineages {cl ,J..,., l D' · .. .. ) 1- 1 1 ' . . • k' ·'- t th t t1... ... : , as~U¡,a · .arw1n1s111.·. ,t 1a1s.01 rruuntams,. spea mg 01 · -empo, ··a ··:(U;

,¡..,....,,,: -··· 1· {. . . d 'b h" proper geo~cw sea mg 0.1 spec1aaon ren era :ra.nc ·. w.g eventi as geo,. '

Introductio11 I .is . '

logically iastantaneoas and tb.at, Iollowíng this tapió origin, most specíes flueruare only mildly in morphology duríng a period oí stasís that usually la&ts ior several míllíon years," (Gould 1982b: 83.}Acetrrdingly, evolutíon by punctuated equílíbría is predíeted to generare a pattern of orgamc evolution resemblíng Fig. r .1, panel B. In tbis relatively pure, hypothetical case-''pure;' in the sense that Iíneages show no graduelísríc change-tJle díreeeíonal trend oí evolution is fueled entite1y by branchíng, The overall pattem is more that of al bnsh than a tres (Gould 1977:. ch. 6).

Needless to ,sa.y, the conflíctíng claíms o1 these theoríes have generated considerable debate in reeent years [see, for example, Gould 198001 Steb- bíns and Ayala. 1~81; Gould 1982a; Stebbíns and Ayala 1985). A.rgument has beea intense, pmtly because both sídes claím causal príodty. On the one hand is Darwíns argument for the predomínam Power of natural se~

Pis~ 1.1. Two models of. oxganic evolutio.n. Panel A is a pom.nD 0:f Dazwin's ~riginal t'Tree oí Lif e" diagJ:~m showing th.e evolutionary emergeace of aew speeíes txt 1 x"', N~, eee.] frotn a oo.mmon ancestot. The X axis (unlabeled in Darwi«s ortginal figure} measnres the mean. value of a given phenotypie character in the evolving populations. In this model, organic. evoluiion rec&ults .from the gr'3du.al aecumu.lAtion of incr~m~ntal chalclgesr a view now ealled "phyletic graduálism . .'' Speciation 00011TS. (at tbe branching po;in.t'Sl bue is net ireaponslble fm tb~ ucnds shown, Panel B shows the oontrastiug p.arte-m oí '"punctuated .eqoillb:ria., 11 i:Jl, wbleh evo1utiDnary uends. result from sudde.n shihs eaused by the orígín .md eninction of speetes, Bach. hypothetic-al shift is .followed by a. períod of sl.asis (idealiaed here as complet~) in the mean phenotypic value oi_ each specles. In this model, orga:nic evolution ccears through rapid speciati-on eve:.nts, The two models shown repr:68ent polar extremes; actual evolution.ary histories cmtld canceivably follow an intcer.mediate pan~m or even so:m:e mix,. ture oí the two, Panel A 1ed:rawn from Darwía 1964 f1859]: fs.clng. p. 1171 panel B redrawn ÍTom Gould J98:1.b: 9r.

Ph-enotypic valúe P.benotyp:ic vslue

-

~

'

-

1 .

l!l.

•• l. w''

PanelB Panel.A

216 I Innoduction

JnGonld f 198.'la: 8:4) admíts tb.at uit is hard to puta number o.n 'lowt and 'predemmanfJ'" a:s osed in di.is p~~ Ke add6! '1Would .fil ·off-the..eufl cWm_fur 94 pet·oent ~ stúflc!eat to rescue - lwm a ch:uge oi winning my· own aipunent by deftning it fut easy victory1'~;

lectíon, on the other is Gould.'s assertion that while ''gradua] phyletie transfonnatíon. can snd dees occnr .... its relatíve frequenc.y is low ánd p'Unctuated equilibrium is the predomínaur mode and tempo tlf evoíu- tionary cbsnge.11~ (r982b: 84.) Tbe íssue remains far from resolved far a number .of reasoas, of which two m.ay be meatsoned here, First1 reeent theoretical work &uggests that what Darwin ealled ''slight, sue(!e&sive,. fa. vorable varlatio:ns'J and natural selectíon can, st least in prineiple, ueate punctuated equilibrla [see, for ínstance, New·man, Cohea, aad Kipuis I9.85J. This impltes that Darwin could be both right a'.bou.t the ,.,majnr mesas of modiflcation''' and, simultaneously, wrong about Its 11ext1ente slownesa,"

Second, gaps or temporal disco:ntiniu:ities in. ehe fossíl reccrd often pre- elude decísíve tests of the rival proposals evea in specíñc, relatively well· documented cases, .. Nowher-e is thís beuer seen than in the fossil evidence fot the rapid. evolutionary espansien of the human bra:in, itself a worthy, lf unusual, example of o.rgani1c evelutioa, On axes like those in the preví .. ous flgme, Fig. 1 • .i summsnzes the avaílable da·tá on the ''endoeranial volume" (ECVJ,. or the ínrernal size of ·the bralnease, for all fo.ssil speeíes ·of homínids between 3 míllíon aad 310 thousand yesrs B.P. {beiore present) .. {For details on data aad metheds, see App. A8.r.J The figure íncludes data both from species belíeved to be directly ances:ttal to ourselves {sueh u the gracíle AusttalopithecClnes, Hamo habilis, and Homo s:rectus}, aad

.from s:pecie.s belíeved to have díed out without descendanes (s.u,eh. as the robust Austtalopithecines and pe-rhaps the Neanderthals]. The tigme reveals no obvious pattem 1of gradual or punc.tuatlonal chang,~ nar even

.Ji!- -~l.1 ·• -f' th In' • f d .. 1---1 .J.!Ul a w:;eeuuli e ma,ture w ' e two. · terpretanon o• tren s is e catiy WDJ,"'

cult beesuae of small sample sízes for most time períods, and because oí substan.dal gaps in the Eossil recotd at key jimctures las, for example; in the vieinity of '.2 million years B.P.). Oíf th,e small out increas:tng number of quanti,tative analyses of these data, s.ome have led to oompletely ~ site c.o.nelusi<i.ns. Fo.r example, a t98·I study of eudoctanial ·volum.es and other· fo:ssil hominid .data by J. E. Cronln and o;thers repo:rt:ed ''no well· do.cument1'd ·examples of either stasis or pllnctuation1' ('p. 1x3J1 while on.e

hil. gh the f nd tha ' - • . , 4i .. ·, '1 ,. ' \~ - • • ~ ~ - ' .. , • ' ~ .~ ' - .• '· .. ' - . ' lt . ' ' .. " . - ' ·•' - .. ' by G .. P .. ~P Ri .· .~tmue m. .. ·. s·ame vear ou · · .. '-~- .. t · Homo erectas was apparen:tly a sub.Je taxon, exbiblting. little morpbo.logical change through ..

10ut. most .of its long history.'' {p. 2.46; but see Wolpoff 19&4-J ln Chapter 8 we will retum to these data and to some of their ,other implic&tions fo1· ·evolutionary anthropology. But ·for now we must conclude tha·t Fig. 1,.2 leavea, open the question of what processes have beeu the main causes ol ttansfom1.atian. in ·tbis importan:t example, the rapid evolution roí tbe humanbmin.

In:trodu·ction I ~1

Sndocra.1r11a1 volume tce)

Fig.. 1.2. Organic ,«.rv-01,ution t8 illustmted by t:he mercase in c:ranial eapaeity armong our homini.d anoostnTS. Th-e figure illusmtes. the expansion ef endocr-amal (intem.al lrrameaseJ volume among pooled samples ·of fossil h.o:mtnid alrulhf1 where eaeh sample contdns al)e,ct~ m~ns of a. aingle species date.d t'O w1tbin ftfty thoU"sand yeau of th.e time $h.G'Wn [e.g., the bar at o.JI million yeal'$ lkP• rep~nt-$. da,ta fo.r 8 skwls., C4".eh dated ~twem 0.151 md o.·8 so millto1i. year;s :tl,P.~. Por .~.eh samp1e, the light bat te.presents tire tange oí cndo.emtú& volume& and. th.e .be.ay.y bar, die standard. eanr of their mean fthe latt.er Í$. ro:ughly eqw.valent t.o a 6tandmd ·de-viation that oo.ntrols far sample si~e)¡ dot& rep.re..sent ~.ia,gle &peoimencs. wttet& to tite left ·flf the 'batís de'!igna«; ~ 1J11~tta:l speei:es ox g¡o:ups .Qf species. Pr'°.m the lmt~Qm;; g = gJaelle .A:.us.t:nlopJthecines tA. afarensla and A. afd.c:anusl; r = :rnbl'l$t AtJS-o ual-opidlecines (A. robllstus and A~ bots.11ii ; 1h = Hamo b,abi/1$; e - Homo erectrts1 a ~ ax4

ebiri:e Hruno ~~:!ii aud a • ~eand.e ·.~. · .s lwho lWíY or may. nat ~~ve ~ eur direct an~ eestors). Only a, · _ . :hacti-011 uí the cotal incxea-se in endoorantal volume ,shown here can. be atfrlbuted to eone;o_mJtam íncrease in bod'y. sW:1 oonsequendy, these data doaument tbe ex- mordi:nat-Y. evolmitma11 lnetea:se in die- sizse of the oqa;n m:nst crucial to our ucapacity for -cultUR. n Af. thc saine thne, hG-we.ve:.r, thc data :r~maio eoe sp.an.e to say with cettainty wheth.er t.he t'fl'mdS flt Úte gt:&.düansm model1 the pmt-CmattñnaJ mOO.tQ,. ÓT some GOmbitlil.., ¡tkJn oi the 1two. See App .. A.8.1 far: 101il1oes. a.ad additional discussion oí data and motbods~

1400 , , ,

,t2-0() lOOO ,

l6l'l0 \.. -

,_

" -- ti• ,... h ·~·-~· l'. b---

•• , .

•--, .. , •• ·- ·--- ' 1'

1

1

1

n-- .-.w ·'' ... rJ¡-. =o•"'•

o.o ¡~. SllM E - n . ·' , 1 LE il&U

ao ,_

Wbat are the sources of isolation and ,disoontlnuity among incipient subs.yS'temsl ln other werds, wha.t permírs deseendaat subunits te di· vergel In ar:gaaic e\tnlutio~ this is equ_ivalent to asking about the causes of reproductive i4olation as requíred tor species f:onnation, or wha:t Could (I~8ic: nvi) has tenned ''the Central problem of fotganicJ revolution.1'

The questíen e.~lls for the .ide,ntlilca'tion ol the most important modes oí specia.tion (as reviewed, ior example, in Bush I97S; Bart0-n and Charlea~

th 8 1 "'---11 ..... • I' b·. . t d t th .d. .,.,•:J:J: t' f wot· 19 ·41, 1~ a con\>.1.ovets1a su Jec _, sn 1:nr .. • e 1 :en-.1nc.a 'ion o. major reproductive iso).ating meehanísms that all.ow genet.ic di_ierenees to, ace.umula.te beeween subpopulations. The importanoe of the ,,isola:tion

· · ""' ·1·1..,.. '""·a-tin:t ... C"',..,..1Ut~"'"'' ·i..Áº been empl.. ... .M ed bv m·~·""v "'·u·~L--~ ín queSJ1.lOn :..u v:&~ .. ~ • +·~1 - ;..:vu l.lilb ·. · .. .. · · 1 .lut.-Z . 7 , 'Jru11.7 ·• · uru ..... , l .. cluding the biologist Richard Alexander who notes that ''witbou.t isola., ti.o:n there wo:uld. be but 'ª síngle speeíes." f 1979: 1,4.} The role of isolation in the divetgence of cultures, as díscussed fo_r examp!e by J. Hil1 f1971.) and P~ Dtener (1980.J, has generally not reeeíved the attentioo. ·that is ita due, except pedlaps in the stmly of Iínguístíc change [see, for exaDlPle, Samuels 1972-:· ch. 6J.

Cultural Bvolution~· An "Untded Theory~'t lf cultures do evolve, then the eoncepe of evolurien .and the quesrions it

raíses would seem to oífer a. valuable perspecríve ior the study ní human cultmal systems. ª1 Ir:0.nically1 althougb anithrupology ,actually bepn ,dur· ing the lti.t c.entuty asan evolutionary scíence, on the ve.ry coatt.ails of the Darwiaian revohníon m biology (see, fot enmple, Kroeber 19601 car .. neiro 19734, 1973b)1 maiostream eonceras in the dli&eipline have foeused eJ,sewhe.r't wr most of thís centu:r~ sometimes wlth a deliberate. bias against evolution (White 196o).~ One reason is. tbat ''theories al cultural evolution did nat .orlginate with. Darwin n-ot were they borrowed from bi .. ology. They a.re as okt .as the anclent Greeks, 11 and they are dl,e~idedly non .. Darwinian in orientatíon and me.chanism fWhite 1959.c: 107). In conttast

11 Ac5 eviden.~ of thts value, in the la:t~ 178&'s (Wt js to say, wdl beíote DarwinJ Sir W'lil;B.....,. ¡,...,._ 1il'IA...-~-i"1.lf!!dl ·t'"-e ,._,.. ...... _ ""ft O('~Mft ,...,...a .l-~ve ai "'º .ilª"""""'"""' f· ..:t.. ¡r.-.t,,.,.;c,-.~---.FW>c" ..... 1lU_uQ.U. JcVW"'"'1- . -.__,,.o·- . -S:.J ...... ~.Y.V ' ·. -~ oo,\~u 'Uf . f~·o u_..._ ... 11, o ·\.UC ll.Wv-UQ&:.Wr ..... ,

.langua;gu-.an insíght whieh grouped. species of idioms inro genera ami 1-en~ intoa fiamily, resmting m a gmuine phylogmy;, pe:dutps dle&st in any ftel'd of knawled¡e.11f&rae:bel'19~

~= ~:er::=2~1~!:iltb;~~b!r~~~:í~:~~~~bie :n:~~:i w.u .a Dw.vmtan lmi-ora D:arwin.''

'fl Antie:llalution~ &e'n~enu hav~ u;sually· be.en direct"Cd ai s:pectiic modolt md 'ÍU~

c:!::;'fu::;1~::1::::;:u,:::::::=:~~°!:~~~~f:::~ a:nd bis lollowea eülkt this c:mtmy. On the one hándJ fas :apreuc:d by a Lau&rr, : :u0,ted in Whito 196o::>~J1, thi& gro~p r~~d-ed ~e ebcory· of ~ltu.Ial evoluti.on dweloped ~y e tbne as ''th.e most man:.e, sterile, md pers1clous, dieozy tn die whole theory of sci•ce~ 11 On me otbu 'bamf, &$.Mead ·l 1964~ 6) o~d, ".aot no point did hu challe..nge d:te .general propos:l~ tians of evruution or question tbe dteo.ry that hWWtD culture$' JMd evolved fxom initWJ:y stmpler fnrm~" A r:ecent exa:mplc of mtievolutionaT-y bias is given m Stoc:king lt9;86; 5a5} wllo q:uo1ct ·thc~ words oE an unnamed &adocultmal anthrop.ologlst, i.r¡ am nol iutem.ued m the evolutton oí an~g, ti

l:nttaduction I i9

to the branching-tree pattern of diveniílcation engendered in Darwínían theory (.no,t to meneíoa the buih pattem oí the reeene punctuationalis.ts), the w'or.ks oí Henry Maine, Lewís H.enry Motgan, Sdward Tylor, Iohn McLennm, and others in the 18,60.'s to 1&901s were unilínear '1stage theo- ríes of history;'1 [See Blute 1979.) As such ·they hea.vily emphasized a no- tion af· sccíal progresa tbtough a sequeace of Ucniío1m stages leading from ''.savagery,11· ''batbarism,'' md the like among nnnstate socíenes through to the ''.dvilization,>1 of eourse, oi Wester.n Eurape.23

Subsequent generatíons o.f social ·scienti'Sts overwhelmin,gly rejeeeed these theories1 and sometimes the wht>:te idea oí cultural evolution aloug with. them, even while embtaeing mote approprlate . and o:ften more D . • ·.,." ... t'· . .l IJ Iture -~!i8CI'"*· u 11. L'o • ~~.Tt •1..a tu,.t. .• ~! ·1 éUWlnlcu.1-n:o 1ons oi. C\l _ . · ... e y¡~~"'· t'U) a .res:w 1 u.llw s .'111 w cuj ~ rural evelntíon remaíned th.oroughly "coatamíaated," as Donald Camp,. bell {1.96;: 23) once put ít, by the ''reactiona.ry políeícal viewpo.int,s of the ptlvileged elassee and racial supremacist apologista fot coloni,alism, ex· clusíeaísr ímmigrat.ion laws, etc,"

In renospece, it seems that a part of the problem seemmed from the failure of these early theorísts to differe:n.tiate berween ·''culture11 and "social system''' and thas, eo borrow agaín from Geettz f 1973: 144-45 ), to distinguish beeweea ehange in the "ordered system o.f meanimg and of symbols'' aad change in ''tb.e actually existing network of social relations.1i

Suxely ehangee in these s,-,st.ems can be, and oiten are, mterrelated, as when new symbo1s ano mem.ing~ are introduced to justify or, índeed, to mystify some change in a soeíal system~ And surely it would have been

.ioolhardy, then as n.ow fsee Hull .1982}, to p.ropose theoríes of cultural evoluríoa that ignore aooial canten and. thus disregard1 for example, ehe cultural ímplications af. power ielatians in a society. But it was alse a mistake to coruound these two phenomeaa, particula:rly if, as more reeene suthors insist [see, e.g .. , Hallpike 1986; Johnson and Rarle 1987·},, ,there can be similu trajectories ,of ''social evolution'' in .societies with very diffu·

1e.nt eultura.1 systems. ·O.f course, the-re m.ay also be differe_nt outcomet to :&ne:ial evolution in societies that began with the same 1eultura.l heritage (see 1espeeially Kitch 19-84; Kifch ami Green 1g&7t. Th.ere may thus be two 1distinctí·ve pattems of ehange, one. for each ,system: stage-wise pathways .of deve1opment in social relatíans, and divergeut1 hr-anching ·trees. oi dif ... ferentiatio.n in culture. Whatever the casef a.tte:mpts by the so-·ealled clo"' sical ev-olutionlsts of the nineteenth eentu_ry to :subsume ali. social and

·cultural chan.ge within unilinear schemes wer-e &urely' destined to fa.il. Eventuall'Yi in th.e mid-194o's, the:re bepn somethi11g oí ,a rebiith oí

in,t.erest f,n fo.rmal evolutionary ·theories oí culture (teviewed. in. PhiW:ps 1971, fOI exampl,e), but scholars were still notably uneasy about the con, ..

23Pot fuller dlseu~i.on. of these th~olies and their impact on anthropology, ~ Wllrk$ by Buunw (19''11 Hards {19~68J md. Stoeld:o.g {.t987~ Tb:e writio¡s. cií Bdwar·d B~ Tylor, particu~ laxly a¡.i:eview~ by 'Buaow {19t):6: ch. ¡)J Opler(t9~4, 1965:), and &tooking {t9-68: ch. s}$ oler m incS:traciiv~ cue exampl:e of tb:e urillmeár app:t.o~-ch.

30 I Introduction

cept of evolu:ticm, and even ,aoout the use of the word, Thus Julian Steward was to wtite in his 1'9SS monograp,b1 Theory ,af Culture Chtmge: 1'Sinee 'evoluti-011' still stto:ngl.y connotes the nineteenth·century view, I heaitate to use it 1but flnd no better eerm," (p .. s.) Con_sequently, ·cultural evoludon has remaiued at the fringes of respecesble, mainstre.am anthropology and is tnday; as Marinn Blute {19791). has argued, "an untried theary.,11 Not sur- ptisingly, culture is therefore malyzed ''much as it would have heen at my' time in. Western hf&tory befure Darwín." {GT,eenwood 1984: 2.0.}

1 would like to offer three reasons why it is importan,t today fot contem .. p.orary autbiopology to try again to develop a genuJne theory oí eulttttal

l · Th' ª ' ' l ld · • -" '·- evo utton.. ' ae i:1rst is simp y to avm . any unpresston w an ana.JS1gous 11 lt ,_J - t" ,ft,¡~ ti .... 'l.. ... ,. ' - .illt"tV l ~'1:1·"· ·'bl " •e·· "db,d'J j,,,¡¡¡, .,.,.. ... .,.4 · cu· :utí.U crea w~üA, uJa• rs, ""-,, 1Pf~..,.~ma, y umm ill-~ .\,;' ·' .u.Ul}t~on .;i., ~-l J · 'L. • ..._ _ _l • a -- d .J.ifi· ~ . ..l L .t L UJ.&t c..utura systems, 1;1ave pet's1su;u in D.Ae ,, unmoea ea t:Ollll :rrom tn.e mommt o.f their creatton .. This reason resta upon the inierenc~ wb.olly justifled! by ,available evídence, 1•· th.at human cultures are ali related by '#descent"'''~that la to say~ by derívatíon or extraction-and that the diieP- enees we observe today are the cumula,tive sesults .of some set of historical divemfying processes .. ln short, anthtopology needs a sequential nan~ fannation theory oJ cultural evclutíon to .suppart i.ts own aeumptions about human cultures and to avoid false and misleading impressions-.

The aeeond reasea is tbat eur undemttnding af eultur41 sy&tems, will be substantially improved bry greater a.tteuti.on to tfle díachroaíe or ,evoluti.o.ns..ry diim.ensiou to eslnne, Here let me fra.me the atgument witk m ins·tructive metaphor. ft s.eems to me that the emerging anthropologlcal consensus, descnbed above, treats cultutes. ve:ry much like cryptogra .. phen' codea" · tbat is,. like tbe sy;stems of symhols. with ce.rtain maxe O.l' less arbitrmy meanings, that people use to mmsmit me¡;&ages through. time, a:nd spaee ·(on thi,s si.milarit)) see alao Douglas 1971}. AccmdinglVí one can. xeaaon~hly imagine three oomplementary appr-oa-ches to the study of the 1'codes,1' tw-0 oí whieh1 in antb.tapolog}'i are alread·y quite sophistt~· ea.ted ... Pit'St., cultures ·ca.n be, a.nd are:, ''dec.ip.he:r~ 11 that is to say their m:ea.niq, in what is oíten referr:ed ro as symbolic 01 semiotie anthmpo1-

:wAnthmpological evidenee hu long tuggmed ,ttmt human ,cultural sys1ems :ftt all t~· bued by desQCD:t1 fomdn¡ what Kroehez (,1·963: :61} call.ed tbe ·~uee of humm cul~;, In a hook s~.e.alJy ch.tll.enging ·unilinea.r vie:ws oí ''social cvolutioD:1'~ for cxample, V., Coxdon ·Childe {t9si~ 16.') wro:t~l "lt. 1·$ oot in th.e least $l,Upri.s-ing that. me dev-ment of ~ietie1 obsé?Ved indillé1tnt pms of ~he Old Wotl..d1 to say nothing ,of dle New., showd ahihit diver- g~twe rather than. prallelbmu in. 1 .pat.tiem analopus, ro org.mie evoll'ltian. Sim1Jm1, in his poslhu.momly published R.ostu of Civiliz.atro11s an.d Cultm:e :f 196.:l), Kmeb:er ,ooJJdnded that 11th.e mmy pm ad present: eulwres ,gJade 11110 one mother tn spa-ce md dme in a. vu-t ~ tinu'Wlí,11 $lleh tJ:at "tth.e rclassfflta.tion •Of l'ttstó:ry and :ooltme secmi'S Wüml tO De mmewhat lik:e th:e t'ladlficatian <lf 1the. iozms of lif~11 (pp. 10, i.2.) Among th:e. .mmy att1m1pt'$ to provide detailed ea.e ttudtes .tli ,.~des.etmt 'widi modliica;ticm11 in a spec:iíi:e w~.mple ,nf enk\ues, une ~y cite thé. 'WOTks o~ <?rc.tnbetg .~ ,the l~g~ges of .AJriéá (J~ <?'r~ee~ l~1'lí111 8" al~ Fwumll kott lfJ77J Cha¡rter; of lb.is bookj and :the Am:edcn IJ1. Greenbexg :its1J1 th.ose of Linooln It~8Iil) 1986,~ :Chapter s of this bOOkl o.rt Imio..Enmpem mvdiology1 md thoa of !p- llin.get.a:L ,(197~) ami M:Ushall [1,gt4J 011the11genetlcmations'1 ot:Polyna.W1 tihlhlg termi .. nol.ogia a.ad of Ausrmn.esim languages more genendly.

Intto.dncti.on I 31

Most oí the conceptual i:s·sues remaining: today in the study oí genes, culture, and. human divexaity relate to two problems: how best to, describe the evolutionary dynam.ics of culture; md ,how ·to· characterize the rela"

S.ome Key lssues in Evolutf,onary, Anthropalogy

ogy, is interpreted or translated, This can be thought of as the intetpretive . . or ''horl.z:ootal'' dimensio.n of cultural analysis {horizontal in the sease of being within or beeween cedes], To quoee írom Ceenz :( 197 3: 14), ''the Who. le l.if:IJ.llt ....,,t. '11. sem ·1·0•,1'c· lllnt't1'""--L "''O ""'"~ 11t1·tro. i,io t. o· aid U8 in tJAin·ino al'> .-_ J_.' r-~) ,.1 ,\n· a '~ ~' ' '-J_ ~ ·~rr\\.!~J. '1 1 ~y.j'• _u.,..·~ w ~-;¡· . ~ -- -· :! __ -, '~~~~' ~!I'

eess to the conceptual world in which oar subjeets Iíve," Second, cultures can be, ami are, studíed in or,der to predict ox explain hwnan hehavior. This can be ·thought oí as the explanatory er ''vertieal1' dímensíon oí cultural malyS"is, fvenical in the sense of &tndying linb berweea eodes on ene level and behavíors on another). Much in the way· that the intetcep~ ·tion and trans.lation of ciyptogr~phers' cedes can Iead to the pred:iction or understanding ot secreetve actions, so too can the analysis oí' cultures help •. t., :- ... t... ,l!. • . 'E h b h . al ' to e:&plilW me w.vers1ty 01 mnan e av1or. cuseoms,

But ecnsíder now the third dímensíon here: one can alse study the evo- lutíonary emergenee ,of the code, That is to· sa:y, one can legitimately seek ·to, oomprehend ehe historical pro-eesses through wbich. peaple have com .. posed, edited, end revísed the codes that gj.ve meaning and directioo to ·their líves .. It should be noted that this "temporal" or evolutionary dime:n-- síon is, at least in principie, .. iully complementa:ry to the oeher rwo: it can be used to ·establish the history of how cedes have come to hsve their preseat r-nn~"urat1·on an d meanina snd how· .... hev h' '·~7·e h1'o.-n-..1naU' V :t.~:· -~.s (~. '1 Uf;-, (_ : ·.:•_: · , _" .u~ WUA~·Ot a,u; .. ~ ~· .. -· ·. · U:I ··.f.· ~:y-~ · ·_ .. _ .a"-V.1-.JA.,(o} .:,,

affected social behavíor and been affeeted themselves in reenm, But, as noted earlier,. tbi:s dimension has receíved the least attention of the three by mainstream anthropology. lnd~ as Frank Livings.tone md others have noted,, ''an iidequa.te model oi cultural evolution ... is still the maior theo:retieal próblem facing anthropol0;gy today.)1 f1981; 645.) It ·cakes little imagiaation, thetefm-e, to prediet that the developm.ent of such a model .and, with it, a lully three..dimensional appTOOch to eulture will a,ddva.lu- able pe1spectiv:e to cultural analysis.

The third reason, why .anthropolcgy will beneílt ftom cultural e:volu .. tionary ·theory ooncerns the con.oept of culture itself: that concept eaonat help but '!:~e strengthene:d, and om u~nderstanding of it enhanced, il we can one day a.cooun.t for trends .in the histarical emergen.ce and divergence of ideatianal systems. As one example ·Of this benefit, it seems to me that tb,e signiflcance oí culture for understanding human behavior stands to be greatly clarifted and. reinforc.ed by renewed attempts to resolve snme key issnes a_bmit. genes· and culture left hanging ·by the soclobiology debate. With this 100 in :mind, let me briefly O·utline same of the mote important ·of tbese issues in ordet W1 have them cleatly· b-efoze us from the &tart.

32 / ln.t1odt1ctío.11

The lssue of Distinction The most basic of all issues facing evolutíonary anthropology concerns

the queseíon, Does culture provide human populations with a second sys .. tem of tnformatíon Inheritance that is truly distínct &om the genes? Is it genuinely appropríate and/or necessary Ior us to dístínguish between

e . · d. . lture as· two difíerent kí índs of ínfl uence on human di'versity? g nes an cu . . . _ . . . . _ \,C; . . . . . _ _ "'"WJ4,4 . . . . .

What, after all, is to be gained by this distinction? That there remains sorne dísagreement on this subiect may come as a

surprise to many readers, partícularly to specialísts in cultural aathropol- ogy on the one hand and in human genetícs on the other. Historically, it would seem that these flelds of inquiry were founded on the assumption that genes and culture do provide the human organísm with two díseínet modes of ínherítance, each with specíalízed fearures that justify and re- íníorce the speeialized study oí them, Reeently, however, a number oí authors have challenged taat assumpnon, arguíng that it leads to a false and misleadíng dichotomy.

The clearest and strongest oí these pronouncements was raísed in a paper by the anthrcpologíst Matk Flinn and the bíologíst Richard Alexan- der (1982). Their critica! revíew of culture theory [íncludíng a number of my own argumental explicitly ehallenged the assumptions, first, that the uníts af mheritance are dístínct berween genetíc and cultural syst_ems; and second, that the mechanísms far the transmíssion of these uníts can also be dífferentíated. In their argument, Plinn and Alexander take the answer to the "uníts question" of cultural evolurion to be "traits," that is, specífic phenotypíc propernes of the organísm. Thev then point out that, witbout exception, the transmíssion of traíts through time in a popula .. non also dependa upon envíronmental ínfluence, the underlyíng genenc integrity of the organísm, and the organism's entíre h.istory of evolution by genetic selection. In short, they say, a trait is never really ''cultural1' as opposed to, or differentiated from, ''genetic''; it is, at best, both of these confounded. A dichot:omy between genetic transmission and cultural tr-ansmission is therefore, in their words {p. 3901, ''unacceptable.'' This crit_icism Ieads them to challenge tbe argument that human diversity is a product of two inheritance systems, one genetic and one cultural, and of

· two correspoodíng sets of units {called ''instructions'' in the speciflc passage they cite). Thís is a common theme (Cloak 19751 Boyd and Richerson (1976]; Lumsden and Wilson 1981; othe:rs). However, tWo sets oí instructions occur in the development of all tt:aits of all organisms: genetic and envi1onmental. No ratíonale has ever been advanced for reptding tlle illfluence of culture on the d.evelopment and ex·

tíonshíps beeween those dynamics and the processes of genedc change, In wy assessment, there remain five issues of paramount importance, each is described below.

Imrodacüon I 3 3

•

1

1

pressioA of hebaviot as oth-ex than a ~ia.l subset of the e:avitonme-Jlt~ The rema:rkahle persistenc.e of such misupportable dichot:rullies seems to attest pt'i~ manly to the hWllaa reluct;m..ce to $00 ourselves as natu1.U ohiects· iu the universe, s:ub'.ject¡ eeen ií in a spedai way, to the same. rales that govern all lire. [p. 39.xl,

In the chsptees that follow1 we will look closely .at this issue, p·a[ticu- larly at two aspects. of it raised by Plinn and Alexand:et .. f.irst, we will in.- vu.tigate the questíon o:f pmper uníts for the study o.f cultural transmíe- síoa, in pait beeanse se much of the debate follows f.rom the ass11mption of a. ''tntlt'' unit. On tltis s.ubj·ect there has a:ris:en eonsíderable dive:rsity of opinion among students of cultural evolution (as revíewed, ÍOJ" example, in. Stuart·Pox.1986}, il onl.y because of the difflcnlty of .B.nding an ,explieit analog in culture for the role of the gene in oipnic eeolutíou. The problem, as Martin D.aly {198:.i.: 4o:t.) has succínetly noted, is that "there are uo segreg.ating pameles unde1lying culture, 11 or at leest no one has satis .. factorily identifl.ed them. Secoad, we will also take a closer loak at :the prop:erties oi culture that purpo.rtedly qualify itas a 1'special subsee" oí' the envíroament, How well does culture ñt into the conventianal genes/ envtronmenr dichot:omy on which thís arg,ument is basedl Are there properties of culture that wanant lts distinction from botb genes and en-

. ' l ... . . h . . . ..l l ~t. • "'d' . . vuonment~ . t 1s my conteanca t · .a.t in Ot\Jer to reso ve uns · · 1sunction íssue" we should in·t,egrate more fully int-0 ·OW' oonception oí culture a number of lessons from tl1e new ideational ehecrles in anthrop:ology.

Tbe lssue of l11depend811ce If we assume fo;r the moment that culture is a dis-tinct ínhentance sys ..

tem, the questien naturally follows1 Is cultural evolution alsil an auton°"' mous .faroe in the shaping oí human diversityl The questíon. is .a.11 the moxe necessazy because we know that th-e struetu1es and ,fun11tions of our '1,capa.eity for culture'' (as described, for example,. in Spuhler 1959; Hol .. loway 197·5b1 Graubar.d 19.85J, particularly those of the bxain and vocal trilCt, are t~hemselves p1odUci.S of orpnic evotution. How mu,c.h freedom L~om·.. &.1.. - (Ulof\¡l;>O pa· n· one Ayna-ct m· . S"~ ,.t... Á ti .J ATt' V''- JJll l-t~~~~ ... "'ll SVd ¡..""m' p,;:. UlC oV··~ '"~.~ ',.,·: M~~I ''' ' .Y,_...11 ·A U~¡,¡- .'l;U' U.Uu&:.A~:AAU.:v ·.¡·~~~' .·, that is to say1 o:ne whose existence dependa so ditectly up.an the p:r;oducts, of otganic e.volutlon?' In what 'MIJ1 does culture temain influenced by its supporting stmctur-es, and thns b:y the genes, a_nd in what ways has the cultural system evolved. a measure of its own independ,e-nce~

This issue has been raiaed in many. diffet-ettt oontexts and by many dliferent authors but, never so: pointedly as by the biologist Edward O. Wlhon. In his book On Hum(Ul Nature, Wilson discusses, th:e develop· ment oí moral systems and .asks: ''Can 'the cultural ·evolution ,of higher ethical values gain a direction. and momentum of its own and completely teplace genetic evolution? [ tbi·nk n·ot. The genes hold culture on a leash~ T.be leash is very long, but inevi'tably values will h.e constrained in accor .. dan.ce with their eff-ects: on tl1e human gene pool;'1 {1.,978: t6·1·~) The meta~

34 .I lntroduction

Tb.e l&s.us of TransfoTmati.on

1l it is true that a.U human cultures are related by deseent, -the question immediatel:y aríses, Wh.at have beea the m.echanisms of chan:ge respon .. &ible foT trllDSfollD.Íll,g earlíer, :ancestral systems fineluding tite original, univerul culture) into the va&t, if dwindling, anay of contemporary cul~ tu . 'Le' ti~ seh d bo ll diJ. • • ' - -·. ,~ ' - l ' .. ' '' - . • . - • . ' - - • ' '··: - • < '.

,_¡ - ',' ' ' _'• '1.: ·'~- .• í' ' ,. ,·-,_• - , .... ''. •' •' ; .. , ', .,.. tures,. . . sm,g ~on . ns . . . ema p1ese.nte. a . "Ve, we may actua y .. st1n guish. two key qu.es:tions in this regartl Pin~ wha.t is the full muge of prn- cesses m1ponsible fo:r ·transfo:rmation1 Wbat are the various mechamsms thmugh which the seate of a given cultural aystem a_t some giv.en time t can 'be modified into a new .state at time .t + t ~ What are the pc-operti:es of the1.e mecba.niams t Do they follow geneial p:attems and reguJlar rules? Seeend, of that r.ange, which mechanism or mechanísms have beea most important in the sense of b.aving tbe gteatest and most enduring effectsl In :other words, is there a :eultural equiv:alent to Darwints predominant Powe:.rt

As befo1:e, theTe exists less than compl.ete agt1eement on these t-0pi.c.s. ín the rooent literatw:e., but in the chapters that follow we will explore some

·OÍ the ptogre.ss. tbat has been made-. A.$ we wil1 see, there a1e. aheady some impriessive results ·to repart with respect to the mnge of forces. A numbet ,of authom, most notably Cavalli .. Sf-orza .and Peldma:n ( 198 J) md Boyd and Bicherson f¡985t, have compiled substantial inventories tl'f the v.arlous mechanisms ~that may, in. ptinciple1 act in 1tramfonning 1cultutlll systems~ In my view, however, the single most important Wlure of these attempts is tha.t none o1 them has to:rwanled a convincing a:rgument, as did. D~ for the ''main but n,ot ,exclusive mean,s.'1 Hence one goal of the book be .. fore you i& to ,attempt sucb. an argument. [t is no longer enougb to sa~ as Margare.t Me~:d { 1964) and. othets have in the past, that cul~:uml evolution aonsists oí ~dlreetional cultural change.'' We n,eed to anderatand why and in what sense it is directi,oll&J and just how f,t is trmsforn1ed. We need, in short, /a system.atic theory of cultural kinetics.

This, however; .leads immediately to a ·fourth concern ..

h ··· 1 . ..11 •· d · 1 ·· 1 e · -.... · h~ h p or JB e ear anui concise yet ecepnve y sunp e. · on:tamw w1.t tn t e image of genes holding culture en a Ieash are a nnmber Gf important 1ques- tion.s er ,groups o:f qnestíons Iíke: (11 Is the leash the same length at ali t,imes .. and all placesi Why or why not? {~}.Are there e-ver instan.ces when the cbain 10Í cammand is reversed, and culture ''drags along'' me leash bear~sl Waen does tbis oecur, ü evert f 3} ts the leash ever so long as to be ineft:ecdve, allowi:ng the ''domestleated pet" to nm free, in effeeti WIL-en do.ea. this happen! And so on, On elose exanrlnation, we can see that ,the value of Wtlsnu's met,apho.r líes not so much in the initial image it presents as in th-e array oí unanswered questions it raíses, These are key questions in the study of ·evolutionary anth1opology-q,uestions to wbich we must remrn in t.his inves.tjgation.

lntroductian I ss

Tbe lssue ,af Difference.

U, Ior tbe salce oí ,argument, we now assume some reselutíon oí the pre- ceding íssues, such tha;t cultural systems are índeed (1} distinct trom genetie systems, f2} in seme w.ays. independent of geaetíc systems, and t.;) fully capable eí ttanslormation, then a whole new lssue presenes . .itseli: Is CU. Itural e"'r.olutí"'o··Q then hm·. ·d·am·· enta·n· ·y d:·iffez·<' ,,·en·t f~·om o· crgan1 íc e·''7;º·,1·un···a·n ' ' ',' ' , .... 1.~. '~ '. l • l . . ' ' ' - . ' \ ' ' ' .'. . , ' ' ' - ' - ' ' .·' 'Ji •. · ' . .· .... , ' . 1 ' . . . .. . . ,. . . . . . . . . . . . . .. .. . . . . . . . ' . . . . . .. . . . . . . ·.. . . . .

in either ru, opersdon or its· eHects? In other wosds, does cultural evolution entail pi.ocesses oz principles that are eíther unpreeedented m. the .e;volution ,of lile or at least substantially diffetent in their logíc 01 fuae- tínn &om those in the arga.nic realm! .l.s there then a basíe, qua:litative dífíerence berweea :the evolutionary· :dynamics of genes md of culturel

On this íssue the emerg:íng líterature ot evolutionary anthropology seems to be divided according to each a.uthor's view o:f the dísnnceíon be .. tween 1·1ultima,te11 and ''proximate'' fonns ,of caesatíon, and h-0w it applies to culture. This lo:ngstanding distinction, forma!ly introd.uc.ed ta mode:m bio.logy by Br11st Mayt {1961; 1503,. see review in Leseo 1981}, requires that causal influenees on behavior be. ·distrihuted beeween these díscreee, polar categoties so tbat ''ptuxlmate causes gove.rn the responses. of [an] ín- dividual to im.mediate factors of the environmen~ while ultima.te causes are responsíble fox the evo.lution ol the particulat DNA pra:gram o.f infor- m.atian [í.e., the genes] with which every iodividual of every specles is en- dowed.,.''~1 Following, thís convention, a numbe1 af reeent anthers have seen fi.t to t:reat culture as a system of proxim,ate causadon and therefore S!S enmpleutl.y eonsíseene with the logic and functíon oí th,e1 ultilOJlte causes. By this. view, culture is the metaph.o:rical ''bandmaiden1' o.f the genes fAlexmder 1979: 143;-43). In eontrast, otber .au.thors hsve argued tbat eulmre provid.es the hum_an 1organism with es"Sentially a secend souree of ultimate causation, Asserting that there are ''.novel forces'' in ·the cultural sya.tem1 unparallel.ed in. organi.c evolution., ·these authors suggest that ''the enstence of culture canse'S human evolution to be funda .. mentally dtfferent from that of noneul:tutfll organis.m&. '1 fBoyd and ru.cber-. san 198 s: 99.J

In the chapters that follow, we wilJ return to this issue of dilference and. the assneíated problem oí causation .. As we wiJll se.e, tbe oonfusi,on and disagreemen·t here arises b-am the .fact tbat cultural causes are neither as

251n hic& boo~ The Bvolutian of Htrilltl11 S:e,gualtty, Dón.ald Symons (1979: 7-8} off:ete.d thi.1 ·~ elabom.tion ol Mayr\ ai:gumenc. upro:ximat~ (lt iuimcdiate1 ~usai analyses con.· s.ider bcJW the 1be'haviot eame to e.xist. .. ~. In o.thet words1 qillestio.ns abou1 th.e pxoximarte caruses oI 'behaviot deal with developmeat, physiruogy, md imJUedi~t.e s·ti:m.ul'tts: they mn- side1 the mdividwal a4imal~s history an.d pte$ent. C'irCUtn$tan.c.es~ . . . 'Uldmate., Ot evo.lutiOD:-- tty, canw ~wll}*US eomider wby dle beh.avtor extst'S. The :all&'W.et:S to questions about uJ .. tbnB:te cauatlo.n will be that die beh1vio1 fwictions :in s:~iic ~ays t.o ma;ximize th:e anima11s inclm.ive 5tness las aJready ddined}. Funciions result from the ~d,on el na,tural se~tion :in 'tke po¡ruJa·ti,~ru; from w~ich th,e mi~.al Ls desce:nded~ .. · .. ~Ue8M118 aboll't the ulmnat~ e~fl. of beh.mnt thus consider primai:1ly the s:j3ttdes"s hlst-0ry.11

36 l lntruduct:ion

The book befare you represents a: ftr,st eff-ort toward the resolution of ·t:he:se and 1elated issues. It is a.n .attempt to foJ:mulate. a getteral theory of culttttlll. evolution, to use that :tbeo:ry ·to predict basic modes o.f relationship between genetic and cul·tural dynamics, and to tes:t th<lSe predictions .against a &ample of d,emanding case sn1dies. In a. general sense its g0:al is to dem.onstmte that an ·evolutionary dimension to the smdy of culture ha.s. much to contribute both to ow undentanding of bum.an diversiry, particuJarly behavioral dliversity/ and to the resolution of age~old ques- tio11s about ~e .and nuriture, genes .and culture. The book is another example oí evolutionary anthropology as previously defined;. it attempts the dual task of sum·madzing, with critica} evaluation1 other maj:ar w<1.cks in this subject uea and of e:xtending the body oí evolving the-0ry in wb,at I believe to be crucial new direetiona. Buildin"' {not uncriticallyJ on my own eatlier ar:guments, 1 p.res,ent tbree main hypotheses that, t(>cgethert

About This Book

The lssue of Coexisten.ce Assuming,. then, that we are able to make sorne headway on Issues 1

through 4 oí this series, the key ,problem remaíns: How do the ptoceases of ge»etic aad cultural evolution relate? What is the range of. p.ossible re- lattonship.s between geneeíc and cultural change, and which of diese re.Ja ... tionships are mosr important ta undeis·tan~ng the evolutio11 o1 human · di .h'.11 Al' th gh d Ií b • . l :vem .. ; .· · . ou , as note ear er, ·su.e,: quesnoas are not eutue-c:'Y new, the-y have re~cently returned to promíneace as a resalt of the sociObialogy- debate. Researchers have asked: f 1 J When does genetíc evolution esuse cultural cbang:el {~} Whe11, oonve1sely1 does cultural evolutio.n cause ge~ netie changel' and (3) When do genes and culture evolve independently, so that cbange in one is not accempanied by change. in the other~ Th,e an- swers to these questiona have noe come easJlt aud even tbe most eamest ol attempts llave somethaes engendered great cantroversy md pelemícs. In r-etrospe"Ct, however, .my imp.ression is that the debate on this íssue has been cnmpounded with differences of opíníon arlsi:ng. hom all of the pre .. v.ious. tour íssues. If we are ahle to ·ptovide some resolu·tion on ehose mere basíe ccneems, Issue s may prove less problematíc than it has thu.s far appeared ..

1'Ultimate11 as genetic causes (fo1· the simple reascn, agall\ tbat g-e-:netic selecti0-n molded the human capadty foy culture In the flrst place) nor are they as '"proximate'' as developmental and physJ,olo:gi·cal causes, In a very real seese, cultural evolutíen is in.termedtate between the pales of this l'h'hv·'IJj;n·ti· nnal .J.t,..t...,,... •. omy,· ......... ,.J' 1 •.• ·rill a....,gu·· e ·th'· at .... hís spe ~ai -at· Uª L-,c: im ·~'" ~ '. U,J.~ - UL\ .. .rl10Li .' '- ,, 1 Gn._Q ' YYA: 1 ~' ',' ' . ¡ : ' .~ Ull:· 1 " ~ ,~.._, • º" ': Q\ J:lilO '~ ,_

- . - - - ' , ,·,_ l , ._, - • - - ·-. -. ·_ - - -·

portant implieadons for ehe tssae ol difference..

lntrodtlction I 3 7

form the heart of the theery of eoevolntioa. Like a boat buílder launching a new ship, naturally l wísh the theozy well. In ·the long run, however, it matters 'llOt how well or long this hoat will. Sail¡ what matters is whether or not beuer bosts can now be built,

The chapters that follow buil!d. s.equentially' from basíc príncíples of cultural and genetíc analysis toward the propasal oí a cultural evolution- .ary theory that is parallel in many respecte to Darwin's the-oey af organíc evelutíon, I use the propoaal, which I call a ·''·,theory oi evolutícn by cultural selectíon," to formúlate a general conceptual framework for the study of gene .. culture .relationships .. Thtough eomparíson of rases and di~ recdoas oí change in the two evolvíng systems, the framew1ork predícts th.e exístence of flve maíor pateems or t'modes'' oí rela:tiomhip berween genes and culture, rwo ·that are fully interactive in the sense descríbed sbose, and three that are ínstesd comparative, In later ehapters, each of these modes is díseussed in some detall and its exístence eonfirmed througb one or more case srudies cbosea far theír heurístíc valué and b ,l. 1i. B i· di . lv the exí roau.e_r unp canens. ···ut ooevo.1utton pre, .cts not ·S:lmp· y _· e exístence of these ftve medes of gene-culture relations1 it· also predicts 1their relaríve importance in the ongoing dynamics of c11lt-ural ehange. We are thus led, by the end of the beok, 001 a general predícríon about the eeoperaríve evo- lutíon o.f genes sad culture in tbe genesís of human diversity.

In. addínon to differences beeween the theory and predicti·ons o.f thís book an.d others in evolution.ary anthropology, there are also dilferenoos in content and ·organization. The ftrst dilfuenee concems strategíes oi ·model building and mo.del testing. Nearly· every oeber recene ,acholarly work on the relatíoas ol genes and culture is beavil:y abstract and quan- titative, requiring readers to have at least a working knowledge of cal .. calus. bnportant assumptia.ns and. ugutnents bave sometimes, been hld· den hehind ovedy :technical jugon, or locked! up inside partía! deriva.oves and double integral&, almost co.mpletely incaccessible to non;mathemati,- clans. Mor-eover, these attempts have aJJ run headlong int-01 what has been termed the ''modeler's dile,mma'': in most instances on·e cannot be pie· clse, general, and realistic all at once (Levtns r1966). In ctmtt.ast, my goal has been to sttiv'e far generali.ty and realism at the expense oi pr-eeJsion. l 'L.-. •'L L t L.- • \.., ' fro • • l d ~.-0 l~Ve ;w1ere1o:re pu ·. more empua0SlS on uas1c concep'lli', pnnc1p es1 an . ·uceu"' nirions dan I bave 1on formulas {most of wbicb4 in fa.et, have been tiele- gared to the .appendixes.). Por example, I de-vote considerable attenti,on in la·ter cbapte1-s to the ''units. question'' o.f cultural ev-0lution,, becaruse earlier quantiitative studies h.ave ·relied upon easily modeled unit~ that .are also misles.ding and unfaithful 1to the recognized ha.sic pro.perties 0cl cul-· tu:re. In addit~ the fram_ewm:k and mo,dels oí gene-culture r·elation- ships that l p,ropose make use of some simple graphic schem.as that d,elilt- erately sacrifice precision in the pursuit of what, l hope, .are gains in die othet dimensions. In this way, I have tried to make accessible both the

38 l lntroduction

Issaes that have surfuced in this area of inquiry .md my ideas for their l .,

reso utten, The second difterence concems my use of case studíes, Barly in this

project, I became convíneed ehat more insigbt was to be gained hom aro in,""depth «eatmcmt of a few such studies thm by any atitem,pt to s.urvey many subjecta. Also, it seemed to me that the Iaek of deraíled e.mpiriw analysis was another of the serious shoncomings eommon to otbex reeeat investiptions in tbis area. I therefore seleeted a small numher of promi&- ing cases tn in,vestigate in as much depth as time and reseurees would al- low. Generally speaking, ehese cases focas oa human behaviota,l di'.Versity,, not because interuting qaesuons and good examples are laeking in the ph,ysialogical and morphological aspeets of human diversi~ but beeause l ~ . .J ed 1:·, • bed ,, ' d1 l.. b eh . . ne~, a more cneamseneec uraverse an neeause .. , avio:r is an espe- cially g-0.od plaee in ·which to study the effects of both genes and culture. I do take up a number of physiological, and morphologieal ·topics along the way, but in ea.ch íastanee the inquiry is related to 01 motivated by speeiík differences in human hebavior. Let me also emphasíze that I make no claim, ahmtt the greater ''rep1esentatlveness11 ol the cases presented below, particularly stnce some of them were ehosen deliberately for their unusual 01 ex:a¡gerated qualities~ lnstead., the cases are meant to illusttat,e theoretical argumenu. They also illusttate aa approach te empirieal ift .. quiry that l believe for. other seasons to have more general applica.bility~

ln coneluding, tbi.s chapter,, let me sketch a brief outhne of the subse- -L.~. ..th th ' • -l L .. - • 'l • l d d que:nt ~ptets, w1 : ~, eir mixture w t®oret1ca' materia an _ ease. stu 8

íes, l begin in Chap'ter 1. with a case study of human beha:rinral diversi.ty that illus:ttat-es hoth the expla.natory dime:nsion oí cultm•l analyeis and the need for a complementary e,volu1Cionaiy dimension. The case con ..

th d. · .í' • • n~l.. 1 · cerns · .e . tvers1ty 01 mama.ge patterns m . wetan, popu atmns, an ex .. ample that stan.ds 0111 in .all ol social science for the variety tand ftuidity} oí marr!a,ge ,ionns observedl in a single popul,ation. My analysis wilJ dem ..

1oustmte tbe power .of culture1s, ideational eod,e for explaimng e\ten these very oomplex pa·tterns of behavior,, but it, will als.o r-aise important ques .. tiOtlS ahout bow that COOe, afteT ali, evolved, tO, MVC its CWt.;eQt WO!tna·

'

·tion oonten.t~ The attempt to aD$Wer this, second questio.n will lead us to some pTnvoca:tive, hypotheses regarding the petsistence of ideational phe"' nomena and on 'to a more general &amewoi:k for understanding cultural cbmgi ' ' , ' \ ' -·- - 'e.

That framewotk, in tum, shares a nu.mber of features with the ooncef>'" twd stmeture of osganic mier:oevolutionary theaty1 which is a subject ·we turn to in Chaptet 3. The focu;s hue is on a second case s.tudy, name]y,· an attempt to explain the gene .. frequency d.i.iere-n.tials that are resiponaihle I th ' b''I- f' • J,.'I·.- 11· . h . l' 1oor · ·. , e vana ,- ,w rat.es o. s1c&.ie-ce. . anemia among t ,- e native popu _ations of tropical West Afrlea. This i's, anothe1 ·classic case of d1versity in the q .. nals .of anthro:pology, one that provide.s the opportunity to review soro.e

lntroducticm I 39

baste cnncepts. aad principles of populacion genetics, and one that hrings us back,. tbm11,-gh no coínerdence, to culture. The ana]ysis will show, thst that geneti,e seleetíon can explain most of thje diffefence between West .Atriean. populations in. the cccurrenee of sickling disease, 'but second, tba1 genetic seleeñen .düfer.entials themselves can be traeed, in part, to cal- tutal diífe1ences among the human inhabitants .of the reglen,

Aftel' a brief critical revíew of ptevious modele for r:elating genes and eulture,. Ch_apter 4 integrates prineiples from Chapter& 2 sad 3 into a general the.ory ol cultural evolution. ln esseace, the tbeoty pr-0poses that two intugaded foyees, oae ealled ''selectiou by eheíee" and the ether "selee- tlon by bnposition,,1' are the main bu·t not exclusive meeaa of ·modi.B.ea ..

ul . ral o1u . . . rU tlu gb- th' í ' th id 1 . ,. ' \ -- ' ' . 1 1 . ' • • • ' • • - • • - 1 .- · · . · ' · ' L : • 1 1 - ~ • • 1 , - ' • , '.' ' • - · e 1 ' , '. ' • - ' ,. tkm .in e tu . eY . tion. Pruna: 1 . ou .. .. . . ese ore~, 1 argue, . e e

a,tional phe:nomena of eultwre are differenrlally socially trmsmitted tbrough spaee and time. Cbapter 4 then assembles these and osher forms af cuJ·tural seleceíen into a conceptual framework int intenela.ting the d,--

.namics of pnetíe and cultural change. Central to, that .&amework is the tpeeial capacity of culture Ior wbat: I call. :self""selection" ·th:at is, the capacity fo:r previously evolved ídeational phe.nomena to govem the raees of social t1ansminion and heaee direct cultural sele~tion. That ca:paclty, in tum, leads me to propase models ol ñve distinct modes of ¡ene--cult:ute relatio.ns. Called '~genetic mediation1'1 ''oultural mediation111 '1.enhance• ment,'' ''neuttality,'' and. '',c>pposition,.'1 these modes .0011stitute the theo ... retical backbone for the :remaindet of the book. Together, they sugeat a new,. more integrat.ed theoty ·of e:volutionary ehange in human popula~ tione.. I call this theory ''eoevolution1'' both beeause it portmys ge~es and. culture as distinct bue intencting '~ttacks·'' of evolutionary cbange, and also beeause it hypothes.izes that genes and culture eften, though not always, ooopecate in the evoJudon of .adapdvely advan.tageous human at- mbutes. ht die balance oí Chapter 4" as a case enmination of th.e mocle called genetic mediation, we mall investigate the hypothesized induence oí genes1 on the cultut"al evolution of hasic oolo:r tenna.

Chapt,er s ·take:s up the logi:cally symmettical case uf cultural. medi~ tion, in which cultul'e is hypothesaed to play a guidmg role in tbe eours_e oí genetic evolution. This m-0de of telatlonship is exemplified by the in- fluen~e that dairying a1td associated cultnl'al phenomena. appea..r to have had in ch.e g;enetic evolution. ·of adult .lacto.se absorption~ In a .similar vein; Ch~pter 6 1explo1es the relatiouship ,ealled. enhancement, in which cultui'e evolve:s in the dkeetion of imp;rove:d human. adaptatton but does s-0 independently of genetic change. This mode is illust.r:a·ted by a oompamtive analysis of incest taboos compil.ed f.rom a world sample of human popula· -tions~ Pmm there, Chaptet 7 goes on to look at neutral and opposing r"ela .. tioos between genes, and culture. The chapter includes diseussion. ,of two suspected examples .of opposition~ the beadh.untl.ng trad:tticm ·Of the Mun- duru·cú· In· ·d1'ans· 1· Am- · · · ·n1·a· a· u-aditmn·· ·.· s·usta1·n- ed• b·,y cho- ··i·c· e for ge· .... nen ' \ ' ' . " ' o ' . . . 1'.1'7.t"'\ ' ' . . . ' ' ' . , 1 . ' ' ' ' '• -

: .. . - ' 1,. ·_ ¡ . ' ••. ~ 'I: " - . , -, . - - ' .'_'' ' ' _·, .. . ' . '

tions despi'te its ptes,umed d.ysfuncti,onality1 and the case of kuru, a lethal

nerve--de¡eneration dísease that reached epidemic proportions among the F 1 of N G. ui 1· bw·e& · · ed ·b· .·. e . .. . . . ,.. ,. .. . . .

' ' ' ' . ·, I • - -:' . ' ~ ',' ' --' . ) ' "-'' ' _, L. ' - " 1 - (_ ·: .-:_~ 1 ' ' ' : ' 1 : J .-. '· '' ore peop . . . ew . . nea as a .. onsequ.ence o . ·. 1. . matntam y -L • 'l.r.1 ill &.l...-. • i d d -! . • h' h cneree, ne W·'.: see wat oppostt on can an , oes eMst wit m iuma.o populatigns, but alao ·that its relatively stahle mani:festatian, g,ene:rally re- s.ults from impo.s:ition ra:ther than ehoíce,

We retum from this odyssey tb.rough theory and examples to a. t~view, hi the final chapter, of the ma.jot assumptions, hypotheses, an.d implica .. tious oí coevolution. Speclal empha:sis is placed'ºª the reJative impo:~ tance ol the .different modes of gene-culture relanoas .. Wt also retum to the ''key issues'' of evol.utialW'.}' ainthrop.ology; which are used so draw ...l.l.ir!f+~ ..... ,.~,n .. in~ be .... de -~~ eeevclu .. ·,on~nr thPi\'rv snd othe r IA:11.1~ ........ nYiQnnQals I U~lowu""'~.u..~uo! ~. ~n:-:C,1_:1~y-~ 1·~&1:_-.¡:,

1·~:1au,· : .. - .. -~~-r-··.·~,~··-·:' •. ., conc!1tde with three predictiotu: th~t comparative modes oí gen.e .. culture relatioos are more commun than interaeti~ modes, that s:eleetion. by ch . ll od hanc ad' in trali ami' th · · · · · · · · · · s e · · · · e · · · · · · · · · · · · · · · ·· · · · ·. · rute usua y p11 · · uee '. .. DJ · . ment gr mg to ueu · · ·· tf; .. ··.·. at most cases of sustained oppositi,on reflec't th.e acnon ·oí imposition~

lnt:raduction J 41 '

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