The Savanna Hypothesis
> No specific time or place
Forces responsible for an adaptation in a period
of evolution
Example: walking (4.4 million years ago)
Example: 2.5 million years ago stone tool use
The Savannah of Africa similar to EEA > More game than tropical forests > Open views, beneficial for upright posture > Suitable for nomadic lifestyle > Resources and refugee
What are Evolved Psychological Mechanisms?
An evolved psychological mechanism exists in the form it does because it solved a specific problem of survival or reproduction
> Solves the problem
> Informative
> Fast, automatic, universal
> Conditional
> Output is physiological, behavioral, psychological
The Brain as a Swiss army knife
- The human brain contains many domain-specific evolved mechanisms
- The brain is adapted to past environments (mismatch)
- Learning and culture require evolved mechanisms
- Nature-nurture is false dichotomy
Distinguish a Proximate from an Ultimate explanation
‘Infant Crying’
Proximate > Separation from caregiver > Cold > Lack of food > Endogenous opioids
Ultimate
> Elicits care and defensiveness from mothers and other caregivers, which will increase the likelihood of survival and hence lead to inclusive fitness benefits.
Bottum up vs Top down
Bottom up
> Observation and then
explain from theory
> How can Donald Trump get that many models?
Top down
> Hypothesis from theory (parental investment theory)
> Women prefer wealthy men because they will provide better for their offspring
Provisioning hypothesis (4)
- Explains high parental investment of males
> Meat is needed - Strong male coalitions (look at armies)
- Sexual labour division in all hunter gatherer societies
> men are physically stronger and hunt big game
> women get pregnant and do most of the child rearing - Reciprocal altruism:
> Hunting success is highly variable
> sharing is a way of storing the meat for lean days
Showing off hypothesis
- Status competition between males. Better hunters receive:
a. more status
b. can take better care of their children due to more
resources
c. sexual favours… - Support for this in many hunter gatherer societies
> Paraguay, Eats Africa, Botswana-Namibia, Indonesia, Australia (turtle hunting)
–> Provisioning and showing off hypothesis are not mutually exclusive
Who is better in object location or object rotation? M vs W
Women location
Men rotation
What is the evolutionary advantage in color vision?(2)
- Better spotting ripe, yellow fruit or edible red leaves
embedded in green foliage - Changes in skin color due to emotional states and social-sexual signals, females may have honed these adaptations for their roles as care-givers and ‘empathizers’
Function of disgust (3)
Evolutionary predictions:
- Disease avoidance
- Moral condemnation (morele veroordeling)
- Potential sex differences?
Pregnancy sickness as adaption: Embryo Protection Hypothesis
> Morning sickness helps to avoid toxins (Profet,1992)
Vomiting expulses possible toxins
Food specific: red meat, alcohol
Especially in first trimester: foetus most vulnerable
3.8% of women with morning sickness have a spontaneous abortion vs. 10.4% of women with no morning sickness
Fear and Adaptive response freeze flight fight submit fright faint
> Freeze: avoid detection (not handy in traffic)
Flight: better run than die
Fight: better fight than die
Submit: apes also do this by avoiding eye contact
Fright: playing dead in the jaws of a lion (and then suddenly run away)
Faint: like submitting
Mismatch fear
Causes of death vs things we fear
Senescence theory
Less selection pressure on old since they do not reproduce.
Pleiotropy
Has positive effect in early life
Negative effect in later live
‘occurs when one gene influences two or more seemingly unrelated phenotypic traits.’
Why do men live shorter than women?
Men have higher potential reproductive success, thus more traits focussed on reproduction, and less on survival
