Psychopathology: Genetic and
Evolutionary Perspectives
Charles Crawford
Department 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
Heritabilities for a Mental and Physical Traits
2
Measure
H
Stanford-Ben IQ
0.65
Otis IQ
0.68
Head width
0.75
Height
0.81
Weight
0.78
Personality Disorders Traits*
Personality
Disorder Traits
Rejection
Restricted Expression
Self-harm
Social avoidance
Stimulus-seeking
Submissiveness
Suspiciousness
Heritability Environmental Variance
Shared
Non Shared
0.35
0.5
0.41
0.53
0.4
0.45
0.45
*Jang, Livesley, & Jackson, 1996
NA
"
"
"
"
"
"
0.65
0.5
0.59
0.47
0.6
0.55
0.55
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
Male mat ing st rat e gie s and t act ics in Blue gill Sunfish
Ge ne t ic st rat e gy
Be havioural t act ics
nest + courtship + care
Parental
h2 > 0
sneaker
female mimic
Cuckolder
h2 = 0
Male Scorpionfly Mating
Male tactics
•Dead insect
•Proteinaceous mass
•Forced copulation
Scorpionfly Mating Tactics
and
Environmental Conditions
Environment
(male-male
Mating Tactic
competition)
Low
Medium
High
Genetically
innat
"mental
e
m
" echanism
Dead insect + courtship
Proteinaceous mass +
courtship
Attempted forced
copulation
h2 = 0
Adaptation Defined
 A set of genetically-coded decision processes that
enabled ancestral organisms to implement costbenefit 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?
Genes: The Evolutionary Perspective
Are genes
involved in
producing the
similarities in
these identical
twins who
were
separated
until middle
age?
Are genes
involved in
producing the
differences
between these
identical
twins?
Identical Triplet Scorpionflies
Reared in Different Environments
Environment
(male-male
Mating Tactic
competition)
Low
Medium
High
Genetically
innat
"mental
e
m
" echanism
Dead insect + courtship
Proteinaceous mass +
courtship
Attempted forced
copulation
h2 = 0
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
Disorder Traits
Rejection
Restricted Expression
Self-harm
Social avoidance
Stimulus-seeking
Submissiveness
Suspiciousness
Heritability Environmental Variance
Shared
Non Shared
0.35
0.5
0.41
0.53
0.4
0.45
0.45
*Jang, Livesley, & Jackson, 1996
NA
"
"
"
"
"
"
0.65
0.5
0.59
0.47
0.6
0.55
0.55
Non Zero Heritability of the Tactics
High
Dead
insect
Ancestral
reproductive
success
Low
Proteinaceous
mass
Forcible
copulation
Low
Genetic differences in competitive ability:
Parasite resistance, growth rate, ...
High
Blue Gill Sunfish: Another view
Ancestral
Reproductive
Success
Cuckolder
Parental
Growth Rate/competitive ability: h2 > 0.0
Blue Gill Sunfish: Adaptation
Fast
Growth
Rate
Slow
Predators
Resources Cuckold
Strategies
Tactics
Proportion of cuckolders
In the population
Parent
Possible Outcomes when Natural Selection Meets
Genetic Variation
Selection
Acts on
Genetic
Variation
Ancestral
Genetic
Variation
Affects of Natural
Selection on Genetic
Variation
Remaining Genetic Influences on
Development
Variability
exhausted
Development freed from genetic
Influences
Genetic influences on development
Remain
Variability not
exhausted
Genetic variation remains and
affects adaptation’s functioning
Genetic variation remains, buy is
not related to adaptations function
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
Yes
Yes
Then:
Contribution
to fitness
No
Adaptiveculturally
variable
Quasinormal
behaviours
No
Pseudo
pathologies
True
pathologies
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
Possible Outcomes when Natural Selection Meets
Genetic Variation
Selection
Acts on
Genetic
Variation
Ancestral
Genetic
Variation
Affects of Natural
Selection on Genetic
Variation
Remaining Genetic Influences on
Development
Variability
exhausted
Development freed from genetic
Influences
Genetic influences on development
Remain
Variability not
exhausted
Genetic variation remains and
affects adaptation’s functioning
Genetic variation remains, buy is
not related to adaptations function
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?