Five-Week-Old Infants.' 'PUB AT Pik 75 NOTE ment;

ED 111 503

AUTHOR

DOCUMENT RESUME

PS 0013 021

Hunter, Michael-A.; Ames, Elinor W.Visual Habituation and Preference for Novelty inFive-Week-Old Infants.'

'PUB AT Pik 75NOTE '12p.; Paper presented at the-biennial meeting of the

Society for Research in Child Development (Denver,,Colorado, April 10-13, 1975)

EDRS PRICE MF-$0.1E HC-$1.58 Plus PostageDESCRIPTORS *Adaptation Level Theory; Behavior Dev ment;

Classical Conditioning; *Dimensional Rrtference;*Infant Behavior; Psychological'TOSting;-ResponseMode; ,Social Science Research; *StimUlus Behavior;Stimufts Devices; *Visual Stimuli

IDENTIFIERS *Habituationo

ASTRACTThis study was designedto determine if the failure

of p revious investigations to find habituation, and response tonovelty in infants younger than 2 months of age was because thestimuli used wee too complex or because a constant number of trialsrather than an individual criterion of habituation was dsed.'A,totalof 24 infants between 5 -and 6 weeks of age were -divided intothreiegroups and given pretest to show that they, had no initial preferencefor tither of two stimuli, which differed' in complexity. Next,- allinfants were given some familiarization with one of the, stimuli,followed by a posttest on both stimuli. Duriflg the familiarizationperiod, the three groups were treated differently: each of two groupswas familiarized with either the complex orc3simple stimulus, and thethird group was familiarized with the complex stimulus, but alloiedonly half as vany.familiatization trials. Results'indicate that: (1)5-week-old infants do habituate to visual stimuli, (2) previous'failures todemonstrate habituation were due to stimulus andprocedural limitations, and (3) preference for novelty is foundfollowing attainment of individual habituation criterion; whilepreference for familiarityis found following a period offamiliarization too short to permit-attainment of such a criterion.(BRT)

***********************************************************************°* Documents acquired by ERIC include many informal -unpublished *

* materials not available from other sources. ERIC makek_every effort ** to obtain the best copy available. nevertheless, items of marginal **.reproducibility are often encountered and this affects the quality ** of the microfiche and hardcopy reproductiolls' ERIC makes available ** via the ERIC DoCument Reproduction Service (EDRS). EDRS is not* responsible for the quality of the original document. Reproductions ** supplied by EDRS are the best that can be made from the original.***********************************************************************

is

,4

at

-U.S. DEPARTMENT OF ALTH

EDUCATION & WE RENATIONAL INSTIT T OF

EDUCATIONTHIS DOCUMENT HAS BEEN REPRODUCED EXACTLY AS RECEIVED FROAATHE VERSON OR ORGANIZATION ORIGIN.ATING IT POINTS OF VIEW OR OPINIONSSTATED DO NOT NECESSA,RILY,REPRE.SENT OFFICIAL NATIONAL INSrUTE OFEDUCATION PO,ITION OR POLICY

Visual Habituation ass Pteferellice for Nmielty

in Five -week -oldqInfantsr: '

MiChaei A. Hunter and Elinor W. Am4s.,

Simon. Fraser University

'-= Po' ' V

Seve al reviewers have pointed out.in recent ,yeas that in spite of

,-.

the imptessive demonstrations of cladsical Conditioning and instrumental

neonates and very young infants, the numbers of tiiials and the.learning in

methodological complexip.es involved in such demonsis:rationstseem to argue

,against those learning mechanisms being the major processes through which'.

in,real life. Some simpler mechanismbehavioural change occurs in the infant

of modifiability seems to be called for,'and at this poin,t, habituation is

the mechanism e!.-.E choice fOr manyexperiMenters.

traditionally been considered neither growth'nor

been demonstrated in a wide range of species, some-orwhich do not show °.

It is a.process.that has./

true learning, and it has

classical or operant learning.

as

There is, a stuMbling ,in the promotion ofLhahitvtion

a major mechanism in the first' feW months, that being the embarrassing°

hOWever,

fact that habituation--at least to visuals been as difficult to

obtain in.young,infants as have more complicated fofmsof learning. In. 1971omm..1 s ...

oz107 Jeffrey and Cohen pointed out that visual-habituation had not been adequately'(...

demonstrated in lnfantsfyounger than 2, mopths old, and Cohen and Gelber (ins ._

t7......1-i,',.

,

. T

,-press) interpret Currently available data op this point-astconflicting. These

..). ...

aireviewers have suggested that age differences in habituation may poesiblY

. .c;

,,5-- .

reflect.basic changes in ,infant- capabilities-with age.' '

. .

.-r

..., PL

. , A ,

Paper presented at meetings of the Society, for Research 1.,n Child Development,Denver; Colorado, April, 1975.

0

C I

;

),

While most investigatorswho have tried,tb habituate infants lessA-

..e - 0 , -\

than 2 months old to visuill stimuli have 'pet with complete failure, there.

. .

ace at least tuT investigators who have foundU

such habituation in some sub-,,,-- c _,

..

, ' 40 . .

jeati.. In-two"studies (Friedman ! ,,, ,1971. Friedman, Bruno ,

4and.Vietze, 1974)

,

Friedman has found habitu*tibd in tome, proportion of neonates, when an

B-second decremeAt in looking time was used as the habipation criterion.

VG 2ar' 'Self (in Press), working in Horowitz's lab, found habituatioil in some of her

r MT,nr

5-weekLold subjects. Both Friedman and Horowitz have"hrgued pfirsuasively

-.v

,-, .

that two months does not represent any deeOpmental barrier for. the capacity.. o

. .,

2 ° ',o'o, , .

to habituate t? Visual stimuli; but instead, that the barrier probably lied -,.- . _ 0

it the stimuli and procedures used.

\ . --)

. ,

We Heartily agree. It is our belief that plevious failures to find

hablu

ation in infants less than two months Old have been due tb the use of,,,,

, .,. '4 ,

a filced number bf habituation trials on.whiqp the stimuli presente&were so ,

Aa

complex that young infants were unabletto habituate to them in the time, 4

'96.. .

allowed.' This belief is based on findings"in/

the literature that:! .,

,,, -* , I ' .

,.

.,,

1) older infants generally habituate faster than do younger infants; f. . t

simpler stimuli produce habituation more readily than do more

complex stimuli,

.

in contrast to the usual finding onidfancs more than-two months old. !

° ' ,

1( ...

.,--- ,

,,,--.

most studies of younger infants have-failed to find'a preferenceNfor a vel,

stiimulusfolloWing a faMiliarization period. If youngersJ.nfoots do.notireally7/ -- . ,,,-- -,

. . '! -'-P . L.

-

0 .

habituate, then ft seeMs. reabonable that they also do not subsequently prefer,_.r: 6

a novel stimulus. But, surpritingly,' there have been severagAindings in young,

infants-of increased prefer4nee for'the familiar stimulus following expoSure to

It e.g, Wetherford and Cohert, 197.3-

r..

-

O

O

".$ -t.

Perhaps 'isis the tie to introduce a necessary distinction, that

bei'ween"habituation and familiarization. Familiarization is .taken be any- , ,

. 4\...

..-14- .

t.

procedure of any duration that gives =fife in4pt percelitual experiente-With,

x. ,:.

-that is; makes him mbrefamiliar with - -a particular stimulus. This.filmiltar-

*

tzat. lOt may Or pay riot be sufficient toprOdUte,habiivafion, which is defined

,

as.a decrement in the infant 's respbnse to the familiarized stimulus down.to4.

. A

, . 5

some criterionC

level-=-for example, to;less thad 507,:ipt the infant's origifill

ro :.

response to 'the stimulus. '.t.

y 9 e

..;-

,. . .

The'finding that inf-Ants who have beer<amiliailized with, but not.,

Aully habituated'to a stimulusl subsequently .prefer.shat stimuluscto a novel (.

.

IL

one.fits very well with optimal level theories like those IfilrBerlyne (1963) or

-

".., .

t..,,

: Hunt (,965), which predict, that as a stimulus bedomes'more famiii!arrthe infant'13 .--

, 7. ft'''' 0 4....... , e.

.

* fixation on it sholack first increase and then decreadb. :Such an invetted1J- .4

shaped fungtipn7is also suggested by thev.backWard habituation curve obtained

4 4

6

7.

, .

Im-four-month AtddThy Mien and Gelber (in press). They found that the curve

...,,

obtained by plotti g backward from thexhabituation criterion did hot have the

slow decline oiler trials characteristic of-ehe forward habituation curve, bUti

astead, the infants' looking increased with familiarization, reaching a peak,

. -

,iriinediateiY before a sudden drop to a low'criterion level.

; . t .,

.

To summarize our own position: we that previous studies have-

generally failed to find habituation and response to nove1,6ii in infants younger.

than two months, old because the stimuli used have been fairly complex; acid a/

.constant nimber of trials rather than an individual criterion of habituation.,:-,-

.

has been used. The usual consequence has been that in the c netant time allow- .,

.0..0" ..,..-- 1,

ed, most,younger infants have either not become familiar with thestimulus At,

cA

r2t.

all--incyhichcase they,show no preference Cfor either the so-called familiar.51, w C,

-," 4

74 *\stimulus.oi the,doi.caIled novel stimulus--or they have become familiarized

..

. .....

.;

-

v,z..N

71,ii. The thr 1p. groups wet.% treated differentlylOnly during the familiar-

ization

.

'pariod:. The first group was run to habituetion'criterion on the

C)

*,

V.-

Ifith, the stimulus to acme extent(but no enough_

A.

to habituate Witin*which-711P

,, . . -

case they,end up preferring the famil am; Wmulus. . D . t:...4, . r V ,

'--

.. . The following-research was undertaken to test this point of view.

4

I , .

- .

Infants 4q three Afferent groups were all given pre-tests to sbdia that they.. . b

had no initiaLpreference for either of two stimuli one' of whiAh was morer. .

complex than the Other. Then, 9-infants Were.given,some familiarization

with one of tiAnli, followed by a posttest/on 1th stimuli .to see if

iseun-'there was. any preference for either the famili#x or the novel .(that

familiarized) stimulutt

C-.

I.

, ,,%

simp er 0f:the two stimulifur hypothe4is was that t

uate rather quickly and then prefer the ,novel stimaqs.

alSo runIt

group would habit-

'the second, group was

t

to the same habituation critelgon, but with the more complex stimulus.4 ..i.

The hypothesit was that although thiS4Toup'would take longer to reach cfiterion,... k--

it would,also,habituat apd.prefer the novel,stimulus.' Finally, a third group.? , ' '

*

S

was familiarized on the same. complex stimulus that was shown to the second

grop, but was allowed only half as manyfamiliarifation trials. It was our.

typotlAsis that thits g oup would-not reach the habituation criterion

subseqpently.,prefer the* familiar rather than, the novel stimulus.VS

Each Of the th e groups contained, eight subjects, four boys

gfrls. The infants

/

vaunteered for the

and would

and four

were between their 5-weelCand 6-week birthdaYs, and were

research by their parents

of three hospitals the Greater

in response to a printed,request

given to mothers in maternity wards Vancouverr... ---a. \

areas IA total of 31 subjects were runbut 7,falled to complete the experiment-

, V '.

al essibn. because of crying and 'fussing. , .,

0

'

The stimuli were black and white checkerboards, one a" x i'and one an

-0 . . . 5

.1W

war

-7 5 -

of, .

, ..

.8 x 8, each 4 1/2 inches: square. These checkerbdardt were chOsen on the

',I ..#.. %I

. .-c '04N

basis of'-dataobtained.bylBrennan, Auld, anemoore-(966);"Who showed that

3 -w eek -olds soaked most at.the 2 x,2,-week-Olds looked 'mostatthe_

t

8-x 8. Subjects Aaliway between 3 and A weeks- -that is, 5 to.'6 weeks, 'old--. .

N .. . ;

rhave been shown to look equally at both stimuli:

. 1 , s ..- v'

. ,

inthe present study a stimulUS, printed/on,a vats card, was mg-,) , ,

.. N IV ! 1 . . .

ented ll'inche's'abOve.the infant's fate and directi); in his line ofvlsion_as'

7(

'heiklay back inside an experimental chamber. Looking time on each trial,

was recorded by an observar,'Who watched the infanf'S ,eyes eirOugh a, peephole

beside, the sipplus card; and pushed-a button that activated a.fustrak event

recorder "whenever the infant was fixating the stimulus. Average agreement

between 2 independent observers on 7 infants Was 93%.

Throughout the entire session atrial started with the infant fixating4

the stimulus, and en del(tbe first time after15 seconds of presentation that7.

the infant looked away from the s4mulus. This' definition of a trial was

."'adopted as a compromise between the convontiOnal fixed length of trial and the

"Want control" procedure used by Horowitz et al. (1972) and by Cohen (1972),

4in which the length of trial is completely_controlledroy the infant, and con-

) ,

sists essentially of the length of the infant's first fixation.

. The inter - trial interval was approximately 10.seconds in duration,

except when it was necessary to take longer to quiet a fussing infant. Unfot-

tunately, with 5-week-olds this is a fairly frequent occurrence. .2 4

..-....0,.

I

Each pre-test and post-test consisted of trials oil each of the two

stimuli, in an ABBA order, A representing the stimulus not being familiariged,

f .

1

and B the stimulus familiarized. Aftqx......the plc-test, members of Group l.were4. ,

. . 1

presented with the 2 x 2 stimulus andrundto.a stringent xxliterion of,habitua-.,, r . . '-.2.1 ' .

,tion. The criterion was-2 consecutive setp of 3 consecutime'triait during.

,) 1# =1 41 6

Cla

. 6

6i

,,. % which the'infanes:average looking time was loss than 1/2 of hisPalierage

,...-

1, ,

.4 looking.time gn tie first 3 habituation trials. .T4e members of-Grogp02 were

.. -\ . ,

habituate( to the same criterion on the .8 x 8 checkerboards The members ofa

,: ,

., ... . ..

Group 3 were a4so presented with the 8.x ficheckerboard, but were allowed only?

,

the average number of familiariz)lajon *rials that MembersgfcGroup 1 lad taken

to'reach criterion on the 2 x'2 cbece;boatd

1"

The results obtaindd for the 3 groups are shown in 3 separate figures,4

(Figures 1, 24.3). 'Each figure shows theApeannumber of ,"seconds per trial

4- spent fixating the 2 x 2 and the 8 x 8 on the pre-test,'and the same 2 stimuli

on the posttest. Between pie- and post=tests is a backward habituation curve,

the plotted points showing mean looking times for all trials on which at least

1/2 of the. subjects in aArOup were represented.

Figure 1 shows the results-for Group 1, which was rito criterion one .

the simple 2 x 2 stimulus. 'All 8 membets of Group 1 habituated. The numberJ

of trials^to.-reach criterion ranged from 10 to 18, vie. a mean of 13.5 trials.

f,

% On the post-test all 8 subjects looked longetat the novel 8 x 8 stimulusthant

. , ,

at the familiar stimulus.2 stimul. .

( -,.

.

Figure 2 shows the results for Group_2, which was run _PO criterion on. ,

,.,

.

,

1 the complex 8 x 8 stimulus. All 8 members of Group 2.habituated. The number

. ,,, ,

of trials 'to reach ',criterion ranged frbm 16' to 39, with a mean of 26 trials-----.._ ,

approximately twice the number of trials taken to teach criterion on the 2 x 2.a

On the post-test all 8 subjectsA.00ked 1onget at the novel 2 x 2 stimulus than

' at the familiar 8 x 8 stimulus.

Figure 3 shows. Group 3,,which. was familiarized with the 8 x'8 stimulus. ..

% .A -

for 13 trials, the dame number\of trials it7took Group 1 to reach criterion on

.2 . .

the i x 2, but only 1/2 the number of trials it took Group 2 to reach criterion

on the 8x 8.,Since none of the subjects in this group camp anywhete near

0

t itikt 7

o

91

7

reaching criterion, their position on the Trials from Habituation continuum

has been estimated by assuming they would have taken'as long as did Group 2

to-reach criterion on the,same stimulus. In this xoup on the post-test all

Ereubjects looked longer at the familiar 8 x 8 stiMO.us than At the novel

2 x 2 stimulus.4

Analysis of variance, of looking times at the two stimuli revealed a

significant Groups x Pre-lost x Stimulus Complexity interaction, F (2, 23.)

6.36,p <AL Individual t-testsOf differences between times spent lodking

atithe'-

2 * 2 and times spent looking at 8 xji showed that while there were no

significant differences during the pre-tests, post-tests in all 3 groups were...

significant at .01 or' better.- More compelling than significance levels, how-

. i'

ever, is the agreement among the subjects. To put it simply, every one of the

16 infants who habituated then preferred the navel stimulus, and every .one of

the8infants"Whowerefamiliarized but not-allowed to reach habituation pre-,

ferred the familiar stimulus.

We believe that the data show:

1. that 5-week-old infantsdd'habituate to visual stimuli,

that previdui failures to demOnstrate habituation have been

due to stimulus and procedural limitations rather'than to any.6

inherent inability of young infants,. .

and 3. that preference for'novelty is found following the'attainment

of a stringent individual habituation criterion, while prefer-

ence for familiarity is foundpfollOwing a period of-familiar-

.

ization too short to permit the attainment of such a criterion.

Berlyne, D.E.behavior.5. N.Y.:

Brennan, W.M.attention354-356.

.References

t

ti

Motivational problems raised by exploratory and epistemicIn S. Koch.(Edj, Psychology: a study of a science. Vol.

McGraw -Mill, 1963. Pp. 284-364.(

, Ames, E.W., & Moore,"Iy.r. Age differences in infants'to patterns of different complexities. Science, 1966, 151,

Cohen, L.B. Attention-getting and attention-hording process6s of infant.visual preferences. Child Development, 1972,.43, 869-879.

°

Cohen,'i.B., & Gelber1

E.R. Infant visual memory. In L. Cohen and1.,

P. Salapatek (Eds.), Infant perception. N.Y.: Academic Press, inpress.

.

Friedman, S.-- Habituation and reebvery of visual response in the alerthuman-newborn. Journal of E erimental Child Ps cholo: , 1972, 13,

339-34C tr

Friedman, S.., Bruno, L.A.,& Vietze, P. Newborn habituation to visualstimulf4, a sex difference in novelty detection. Thumnal of Eicperi-

l'ilental Child Psychology, 1974, 18, 242-251.r6

Horowitz, F.D. (Ed.) Visual atterities:, Viary stimulation; anallanguage discrimination'in,younk".-infants. Monographs of the Societyfor Research in Child Development, in;press.

°`Horowitz, F.,'Paden, L.., Bhana, W., & Self, P. An '

-procedure for studying infant visual fixations.ology; r972,, 7, 90.

Hunt; J. McV. Intrinsic motivation and ita role inOpment. Nebraska SymPasium on Motivation, 1965,

'Infant Control"Developmental Psych-

psychologicaldevel-ki..., 189-282.

Jeffrey, W.E., SiCohen, L.B. Habituation in the human-infant. In H.

Reese (Ed.), Advances in child development and behavior. Vol. 6.

- N.Y.: Academic Press, 1971,.63-97.

Self,.P.A. The addition of puditory,stimulation (music), and an inter-spersed stimulus procedure to control visual attending hehavior,ininfants, In 'Horowitz, F.D. (Ed.), Visual attention, auditory.,stimu-lation, and language discriminatIon in young infants. laloitalEL_soLthe Society for. Research in Child Development, in press.

0

, Wetherford; M.J., & Cohen, L.B. Developmental changes in infant visualpreferences for novelty and familiarity. Child Development, 19'13,

44, 416-424.

ti9

t.'

Z.,,

o

talk

PR

E

20lb

rim!".

TR

IALS

FR

OM

CR

ITE

RIO

N4

,Figure I

Pre, post, and

ha btimation

looking time for Group 1, run to

habituation criterion on 2 x 2"stimulus..

t

°

44-o2.

X8x8

PO

ST

4,

L-#

2

.2

88..per

5

2520

O1510

gmm

17T

RIA

LS FR

OM

CR

IT'R

ION

Figure,2

Pre, post, and habituation looking time for Group

hahituation criterion on 8 x 8 stimulus.

28

xx8

PO

ST

.

2, run to

f

0..

10go,

w

28

12520.

151

xx

2-.8.

PR

E

)

rl

v.*

.ES

TIM

AT

ED

TR

IALS

FR

OM

CR

ITE

RIO

NFigure 3

I

Pre,_post,'ancl familiarization looking time for Group 3,

familiarized, but ndt reaching criterionon 8 x 8 stimulus.

-28

xx

28

-PO

ST

°