Psychopathology: Genetic and Evolutionary Perspectives Charles Crawford Department of Psychology Simon Fraser University E-mail: crawford Website: .

Psychopathology: Genetic and Evolutionary Perspectives

Charles CrawfordDepartment of Psychology

Simon Fraser University

E-mail: crawford

Website: http://www.sfu.ca/faculty/crawford

David Rosenthal’s Genetic Theory and Abnormal Behavior

Of all the facts of life, the most important is evolution. If psychology is to take its legitimate place among the family of life sciences, it must eventually integrate its basic theories and facts with those of evolution. If we are to understand abnormal behavior, we must do so in the context of a psychology so conceived and so formulated. These three simple statements constitute the conceptual framework that hopefully will lend vitality and a sense of orientation to the chapters that follow. (Rosenthal, 1970, p 1).

Evolution is rarely mentioned in remainder of the book Why?

What Behaviour Geneticists Want

Mode of inheritance Biochemical pathways Relation between alleles and

physiological development Relation between physiological

development and behaviour

When Mendel's Laws Don’t Work

Incomplete penetrance Only some individuals with gene are affected

Variability in expressivity Intensity of expression varies between

individuals

Many genes affect the trait Producing a normal distribution

Measure H2

Stanford-Ben IQ 0.65

Otis IQ 0.68

Head width 0.75

Height 0.81

Weight 0.78

Heritabilities for a Mental and Physical Traits

Personality Disorders Traits*Personality Heritability Environmental VarianceDisorder Traits Shared Non Shared

Rejection 0.35 NA 0.65Restricted Expression 0.5 " 0.5Self-harm 0.41 " 0.59Social avoidance 0.53 " 0.47Stimulus-seeking 0.4 " 0.6Submissiveness 0.45 " 0.55Suspiciousness 0.45 " 0.55

*Jang, Livesley, & Jackson, 1996

Focus of Genetics

How genetic differences between individuals produce differences between individuals in a constant environment.

Darwin’s

Finches’

beaks

Beaks: Tools For Survival, Growth, and Reproduction

E.O. Wilson’s Definition of Adaptation

An anatomical structure, a physiological process, or a behavior pattern that makes an organism more fit to survive and reproduce in competition with other members of its species

Examples: Beaks of finches Binocular vision Bipedalism

Note the word “ancestral” not in the definition

Blue Gill Sunfish: Lifehistories

Parental Grow slowly, mature late Courtship, paternal care

Cuckolder Grow fast, mature at young age Young - sneak fertilisations Old - mimic females

Genetic strategy

Parental

h2 > 0

Cuckolder

nest + courtship + care

sneaker female mimic

h2 = 0

Be havioural t act ics

Male mat ing st rat e gie s and t act ics in Blue gill Sunfish

Ge ne t ic st rat e gy

Parental

h2 > 0

Cuckolder

nest + courtship + care

sneaker female mimic

h2 = 0

Be havioural t act ics

Male Scorpionfly Mating

Male tactics•Dead insect•Proteinaceous mass•Forced copulation

Environment

(male-male competition)

Low

Medium

High

Mating Tactic

Geneticallyinnate"mental"mechanism

Dead insect + courtship

Proteinaceous mass + courtship

Attempted forced copulation

h2 = 0

Scorpionfly Mating Tactics and

Environmental Conditions

Adaptation Defined A set of genetically-coded decision processes

that enabled ancestral organisms to implement cost-benefit analyses in response to specific sets of environmental contingencies, and

that organized the effector processes for dealing with those contingencies so that the allele(s) producing the decision processes were reproduced better than alternate allele(s) Examples: fever, beaks, recognizing kin, warfare

What is the role of gene differences in producing behavioural differences?

Are genes involved in producing the similarities in these identical twins who were separated until middle age?

Genes: The Evolutionary Perspective

Are genes involved in producing the differences between these identical twins?

Environment

(male-male competition)

Low

Medium

High

Mating Tactic

Geneticallyinnate"mental"mechanism

Dead insect + courtship

Proteinaceous mass + courtship

Attempted forced copulation

h2 = 0

Identical Triplet Scorpionflies Reared in Different Environments

Conclusion

Gene differences do not produce the behavioural differences

Genes that all male scorpionflies have enable then to choose the tactics used

The design of their mating processes is innate It limits their ability to use other mating tactics Dose zero heritability mean genes are not involved

in behavioural differences?

Logic for Innate Design

If alleles at a large number of loci are necessary for the development of a complex adaptation,

if sexual recombination continually reshuffles alleles at these loci,

then, it is unlikely this reshuffling has a major effect on the adaptation's functioning.

Therefore, the genetic design of an adaptation is likely innate.

But what of the non zero heritabilities?

Personality Disorders Traits*

Personality Heritability Environmental VarianceDisorder Traits Shared Non Shared

Rejection 0.35 NA 0.65Restricted Expression 0.5 " 0.5Self-harm 0.41 " 0.59Social avoidance 0.53 " 0.47Stimulus-seeking 0.4 " 0.6Submissiveness 0.45 " 0.55Suspiciousness 0.45 " 0.55

*Jang, Livesley, & Jackson, 1996

Non Zero Heritability of the Tactics

Ancestralreproductivesuccess

Genetic differences in competitive ability: Parasite resistance, growth rate, ...

Low

High

Low High

Dead insect

Proteinaceous mass

Forciblecopulation

Blue Gill Sunfish: Another view

Growth Rate/competitive ability: h2 > 0.0

Parental

CuckolderAncestralReproductiveSuccess

Blue Gill Sunfish: Adaptation

StrategiesGrowth Rate

Fast

Slow

Tactics

Cuckold

Parent

Predators Resources

Proportion of cuckoldersIn the population

AncestralGeneticVariation

Variability exhausted

Variability not exhausted

Development freed from geneticInfluences

Genetic influences on developmentRemain

Genetic variation remains andaffects adaptation’s functioning

Genetic variation remains, buy isnot related to adaptations function

Affects of NaturalSelection on GeneticVariation

Remaining Genetic Influences onDevelopment

Selection Acts on GeneticVariation

Possible Outcomes when Natural Selection Meets Genetic Variation

When Mendel's Laws Don’t Work

Incomplete penetrance Only some individuals with gene are affected Adaptation-environment interactions

Variability in expressivity Intensity of expression varies between individuals Adaptation-environment interactions

Many genes affect the trait Producing a normal distribution Genetic variation at protein level

Evolutionary Psychology

Stresses that existed in ancestral environments Finding a mate

The psychological mechanisms that evolved to deal with those stresses. Evaluating physical features as guide to health

The way those mechanisms function now. Men and women on TV

Toward an Evolutionary Classification of Behaviour

Adaptation failure: Cybernetic dysfunction Organic dysfunction

Problematic behaviours: True pathologies Pseudopathologies Quasinormal behaviours

Adaptive-culturally variable

How Adaptations Fail: A Computer Analogy

Adaptation's cost-benefit structure provides inadequate or inappropriate decisions because of:

Cybernetic dysfunction - Failure of the adaptations information processing system True altruism, nursing failure

Physiological dysfunction - The neural hardware in which the information processing system is realised PKU, Korsakoff’s psychosis

Adaptation functioning: Then and now

Now: Contribution to well being

Adaptive-culturallyvariable

Yes

Yes

No

No

Pseudopathologies

Quasinormalbehaviours

Truepathologies

Then:Contribution to fitness

True Pathologies

Have deleterious consequences for individuals possessing them, irrespective of whether they are living in an ancestral or current environment.

Examples: PKU, brain damage, Korsakokff’s syndrome Autism Maternal diabetes, hypertension

Malfunction of or cost of adaptation

Adaptive-Culturally Variable Behaviours

Behaviours that vary in time & space, but that serve adaptation’s original function.

Examples: Language learned - Swedish, English, Portuguese,

Esperanto, etc Athletic sports - Baseball, cricket, hockey Co-operation, reciprocity Cheating, self deception, theft, war,...

Pseudopathologies

Behaviours that contributed to ancestral fitness, but that are no longer adaptive, ethical, or normal. Excessive male sexual jealousy Prostitution Anorexic behaviour Teenage gangs

More will emerge as we move further and further from our ancestral environment.

Quasinormal Behaviours

Behaviors that would have detracted from ancestral fitness, but that have become culturally acceptable and even encouraged Adoption of genetically unrelated children. Innocent until proved guilty. Recreational sexual behaviour. True altruism Equal treatment of women

Not result of evolved adaptation to produce them

Quasinormal: Why they can be problematical

The cues for managing behaviour may be inadequate

• Adoption of unrelated children

Not all members of a social group will make the same cost-benefit analysis, producing conflict Feminism, polyandry, stock market

Conflicting inputs to information processing mechanisms may produce psychological conflict Recreational sexuality, innocent until proved guilty

AncestralGeneticVariation

Variability exhausted

Variability not exhausted

Development freed from geneticInfluences

Genetic influences on developmentRemain

Genetic variation remains andaffects adaptation’s functioning

Genetic variation remains, buy isnot related to adaptations function

Affects of NaturalSelection on GeneticVariation

Remaining Genetic Influences onDevelopment

Selection Acts on GeneticVariation

Possible Outcomes when Natural Selection Meets Genetic Variation

Genetic Variation Exhausted: h2 = 0.0

Development freed from genetic influences The tabula rasa Therapy?

Genetic influences on development remain Constraints on possible change Therapy?

Genetic Variation Remains:h2 > 0.0

Specific genes affects adaptation’s development - Genetic perspective Balanced polymorphism

• Sickle cell anaemia

Psychotherapy?

Genetic variation remains, but not related to adaptation’s function - Evolutionary Psych. Psychotherapy?

David Rosenthal’s Genetic Theory and Abnormal Behavior

Of all the facts of life, the most important is evolution. If psychology is to take its legitimate place among the family of life sciences, it must eventually integrate its basic theories and facts with those of evolution. If we are to understand abnormal behavior, we must do so in the context of a psychology so conceived and so formulated. These three simple statements constitute the conceptual framework that hopefully will lend vitality and a sense of orientation to the chapters that follow. (Rosenthal, 1970, p 1).

Would evolution still be rarely mentioned in remainder of the book?