Transcript Evolutionary Psychology - HomePage Server for UT Psychology

Evolutionary Psychology
Evolved Mechanisms
• ALL psychological theories imply evolved
psychological mechanisms
– Where did these mechanisms come from?
– Why do they exist?
• They evolved to solve recurrent adaptive
problems in our ancestors!
• Evolution by natural selection is the only
viable answer
• Ultimate explanations
Evolved Mechanisms
• What are the characteristics of evolved
psychological mechanisms?
– Blind design (not made from scratch)
– Gene selection: selfish genes
– Domain specificity
• Swiss army knife
– May emerge at any point in development;
need not be present at birth
Environmental Input
• Is evolutionary psychology genetic
determinism?
– NO
• All evolved psychological mechanisms are
dependent upon environmental input
– Internal or external
• Even biological/genetic physiological
adaptations such as muscles require input
(nutrition and exercise) to develop and maintain
– Psychological mechanisms are no different (language)
Evolved Mechanisms
What about culture?
• Culture is often used as an explanation for human
behavior and differences between individuals and
groups
• But culture is not an explanation for anything – it
requires an explanation!
• The existence of culture requires evolved psychological
mechanisms
• Cultural differences are the result of varied
environmental input
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Availability and type of resources
Population density
Male to female ratio
Presence of geographic barriers/isolation
Sex Differences
• Males and females have faced some
separate adaptive problems throughout
our species’ history due to both biological
conditions (reproduction) and social
conditions (gender roles)
Sex Differences
• Males: hunting → greater upper body
strength and greater spatial rotation
ability for throwing spears
• Females: gathering → better spatial
location memory for finding and
remembering good food sources
Sex Differences
• Males: tribal warfare, group hunting →
strong coalitional tendencies
• Females: patrilocal societies → weak
coalitional tendencies
Sex Differences in Mating
• Males: paternity uncertainty → sexual
jealousy
• Females: need for resource investment for
children → emotional jealousy
Sex Differences in Mating
• Males: cryptic ovulation → long term
relationship with frequent sex
• Females: dual male strategy of long term
and short term mating → discerning
whether a male views her as a long term
or short term mate
Important Findings of EP
• Altruism and kin selection
• Why are we nice (self-sacrificing) to each
other if genes are “selfish?”
– We are most likely to exhibit kindness to
people who share our genes
– Reciprocal altruism with friends has benefits
(i.e., can be selfish)
– Altruism can raise social status and attract
mates
The Wason Selection Task
Each card has a number on one side and a letter on
the other. Indicate which cards you need to turn
over to see if any violate the following rule: If a
card has a D on one side, it has a 3 on the other.
The Wason Selection Task
Imagine you are a bouncer at a bar. If a person is drinking beer,
he must be at least 21 years of age. One side of each card shows a
person’s age, and the other side tells what he or she is drinking.
Indicate the cards you need to turn over to find out whether
anyone is breaking the law and needs to be thrown out of the
bar.
Important Findings of EP
• Social exchange/cheater detection
• Humans are very good at interpreting
conditional rules of social contracts
• Social exchange problems on the Wason
selection task are always solved much
more easily than corresponding logic
problems
• This is true even if the social contract is
unfamiliar
Which figure is most attractive?
Important Findings of EP
• Universal preference and importance of waist-to-hip ratio in
females
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Fertile women .67-.80
Lower is better
Average preference in all cultures surveyed = .70 (range = .68 to .72)
Average actual WHR among females in the United States = .80
• Honest signal of health and fertility
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Greater fertility
Reduced risk of cardiovascular disease
Reduced risk of diabetes
Reduced risk of at least 7 different types of cancers
Reduced risk of cognitive impairment
What does it all mean?
• Humans are adaptation executors, NOT
fitness maximizers!
• “Mean genes”
Recommended Reading
• Evolutionary Biology
– The Selfish Gene by Richard Dawkins
– The Blind Watchmaker by Richard Dawkins
– The Ancestor’s Tale by Richard Dawkins
• Gene/Environment Interactions
– Nature via Nurture by Matt Ridley
• Recent Human Evolution
– Before the Dawn by Nicholas Wade
• Evolutionary Psychology
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The Evolution of Desire by David Buss
Survival of the Prettiest by Nancy Etcoff
Sperm Wars by Robin Baker
The Dangerous Passion by David Buss
The Murderer Next Door by David Buss
Mean Genes by Terry Burnham & Jay Phelan