Transcript Evolutionary Psychology: Counting Babies or Studying

Evolutionary Psychology: Counting
Babies or Studying Information
Processing Mechanisms
Charles Crawford
Department of Psychology
Simon Fraser University
Burnaby, BC, Canada
E-mail: [email protected]
Website: http://www.sfu.ca/faculty/crawford
1,000,000 years
QuickTime™ and a
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Infinitesimal
segment of
evolutionary time
Given the Difference Between
Then and Now
• Can we use the Theory of Evolution by
Natural Selection in the study of the limits
of human nature?
• If we can, how can it be done?
• By the study of adaptations: Then & Now
A Central Problem of Humanity
• How can we set up societies
– that are founded on moral principles, and yet
– are pliable and comfortable enough for people so that
the society will persist?
• Example: Collapse of the USSR
• Resolving “naturalistic” and “moralistic” fallacies
• Is there a role for evolutionary psychology?
Outline
• Adaptations
– As anatomical structures,..
– Fitness maximization
– Criticisms
• Adaptations
– Information processing mechanisms
– Environments and adaptations: Then and Now
• Validating evolutionary explanations
Darwin’s
Finches
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
– Upright walking
• Note the emphasis on reproduction
Beaks and Reproductive Success
Many traits contribute to
survival and reproduction
in different species,
including humans.
What role for
reproduction in the
study of adaptations
Homicide and Reproductive
Success in the Yanammo
Implications
• individuals were selected to behave to maximize
their reproductive success
• adaptations are manifest at the level of behavior
• innate specialized psychological mechanisms are
not required for maximizing fitness
• therefore, differences between ancestral and
current environments are less significant than
some claim
Criticisms
• Although adaptations were selected because they
maximized ancestral reproductive success, does
this mean they act to maximize it now?
• Is behavior the result of the actions of
psychological mechanisms?
• Can natural selection select for general purpose
mechanism?
• How critical are differences between ancestral and
current environments in research?
What Do We Need?
• a more adequate conception of behavioural
adaptations
• methods for studying behaviour producing
adaptations
Fever as an Adaptation
• raising body temperature to help the body
fight parasitic infections
• processes information about the invaders
and the body’s ability to resist them
• benefit: destruction of parasites
• costs: energy requirements, damage to body
Male Scorpionfly Mating
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, recognizing kin, forming social
contracts, deceiving oneself, ...
Environments and Adaptations
•
•
•
•
Innate adaptation
Operational adaptation
Development environment
Immediate environment
Innate Adaptation: Adaptation as
Design
• The species typical information encoded in
particular gene(s) that direct the development of a
phenotype in such a way that the genetically
encoded information was passed from generation
to generation more effectively than information
from alternative gene(s).
– Example: Genes for the development of intellectual
reasoning ability.
Operational Adaptation
• The phenotype that develops on the basis of
genetic information in conjunction with the
internal and external environment of the organism
during development.
– Example: Psychological mechanisms for engaging in
intellectual reasoning
Developmental Environment
• Ancestral: Ancestral environmental conditions
during development that shape the functioning of
the ancestral operational adaptation.
– Example: Hunter-gatherer teaching, gossip, and the
development of intellectual reasoning
• Current: Environmental conditions that currently
shape the develop of the operational adaptation.
– Example: TV, schooling,, gossip, and the development
of intellectual reasoning ability
Immediate Environment
• Ancestral: Ancestral conditions that activate the
operational adaptation to produce an episode of
behaviour.
– Example: Reasoning about kinship relations
• Current: Environmental conditions that currently
activate the adaptation.
– Example: Doing the GRE
Intellectual Reasoning: Then and Now
Innate adaptation: Genes for
organizing intellectual development
Old operational adaptation:
Psychological processes for reasoning
about abstract relationships
Gossip, informal
Schooling, &
story telling
Reasoning about
particular kinship
relationships
Newer operational adaptation:
Psychological processes for reasoning
about abstract relationships
The GRE
TV, reading, &
Formal schooling
Evolutionary Psychology
• Problems faced by our ancestors
– Understanding your tribe’s kinship structure
• Information processing systems that
evolved to help provide a solution
– Intellectual reasoning processes
• Way evolved mechanisms function now
– Doing the GRE
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 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
Evolutionary and NonEvolutionary Explanations
• Should evolutionary and non-evolutionary
explanations be compared when testing
evolutionary explanations?
Relation of Non-Evolutionary and
Evolutionary Explanations
Evolutionary
theory
not used
Warp drive
explanations
Evolutionary
Explanations
Good non-evolutionary
explanations
Example: Brother-Sister Incest
Avoidance
• close inbreeding is detrimental to survival
and reproduction
• ancestral individuals avoiding it would have
had better lifetime reproductive success
• hypothesized adaptation: intimate rearing of
brothers and sisters attenuates sexual
attraction when they are adults
How do We Validate Evolutionary
Explanations of Human Behaviour?
• by modeling ancestral selection processes to
determine if the adaptation could have evolved
• cross cultural studies to determine how the
adaptation functions in different environments
• experimental studies to make causal statements
about psychological mechanisms
• locating the basis of the adaptation in nervous and
endocrine systems to give biological credibility
Benefits of such a mechanism:Effects of
Inbreeding on Mortality
Two
Japanese
Cities
Ancestral Fitness Model
• Could such a mechanism have evolved?
• Independent variables
– genetic relatedness
– sex of individuals
• Dependent variables
– lifetime reproductive success
• males
• females
How the Adaptation Functions in
Different Environments
• Marriage and incest rules in many cultures
– rules supporting variety of functions exist
– how many of these support hypothesis?
• Naturalistic experiments in various cultures
– kibbutz marriages
– sim pau marriages
• Can causal statements be made?
– No
Experiments: Random Assignment
of Treatments to Subjects
Age Intimate Rearing Begins
Infancy
BrotherSister
No
Yes
Adult sexual attraction
Genetic
Relationship
Not
Related
Post adolescence
No
Yes
The Nervous and Endocrine
Locations
• ????????????????
• Need not be a specific location for, say,
incest avoidance.
A Central Problem for Humanity
• How to set up societies
– that are founded on moral principles, and yet
– are comfortable enough for people that the society will
persist?
• Balancing ideology and reality
• Dealing with “naturalistic” and “moralistic”
fallacies
Preventing Brother-Sister Incest
• Strict laws with severe penalties?
– Apache Indians of the American planes
• Relaxed, intimate rearing conditions
– Tellensi of Africa
Darwin’s Wisdom
Man with all his noble qualities, with
sympathy that feels for the most debased, with
benevolence which extends not only to other
men but to the humblest of living creatures,
with his god-like intellect which has
penetrated into the movements and
constitution of the solar system -- with all
these exalted powers -- still bears in his bodily
frame the indelible stamp of his lowly origin.
(Charles Darwin, The descent of man,
1871/1898, p. 634.)
The Naturalistic Fallacy: “What is, is
what ought to be”
• Women are less sexually aggressive than men,
therefore, they ought to be less sexually
aggressive.
• Women are lighter than men, therefore…
• But are there constraints on what can be changed?
– Sexual aggressiveness
– Height?
The Moralistic Fallacy: “What
ought to be, is what is”
• Women and men ought to have the same sexual
agendas, therefore, they do, and if they don’t…
• Women and men ought to be the same weight,
therefore,…
• Must what “ought to be” exist?
• Tragedies of history
• Can evolutionary psychology help with the
naturalistic and moralistic fallacies?
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, but is
not related to adaptations function
Wilson on Natural Selection and
the Human Mind
• Camus said that the only serious philosophical question is
suicide. That is wrong even in the strict sense intended. The
biologist, who is concerned with questions of physiology and
evolutionary history, realizes that self-knowledge is constrained
and shaped by the emotional control centers in the
hypothalamus and limbic system of the brain. These centers
flood our consciousness with all the emotions--hate, love, guilt,
fear, and others--that are consulted by ethical philosophers who
wish to intuit the standards of good and evil. What, we are then
compelled to ask, made the hypothalamus and limbic system?
They evolved by natural selection. The simple biological
statement must be pursued to explain ethics and ethical
philosophers, if not epistemology and epistemologists, at all
depths. (Edward O. Wilson, 1975)