Evolution of human behaviour

Evolution of human behaviour

1. Why study humans from an evolutionary perspective? why do women like men with lots of money? why do we cooperate with each other? why we have such big brains? why do we use language? why do we have theory go mind? why?.... the processes of natural selection and adaptation can offer answer..

2. Tinbergens 4 whys? (1963) why is the baby crying?; proximate/ mechanistic explanation; baby is hungry, brain mechanism=crying. Developmental/ historical explanation; baby has learned that crying=food. Phylogenetic/historical explanation; all primate socialise to attract care-giver. Functional/ ultimate explanation; crying bonds with mothers and baby/crying alerts mothers problems etc.

3. Life is the product of successful strategies; during evolution, selection favours individuals who adapt strategies that maximise their contribution to future generations. Evolution 'designs' life, equipping individuals with the tools they need to survive and reproduce. So, we ask- what is the function of behaviour ? How does it contribute to survival/reproductive success? What do people do what they do?

4. Why is this controversial? Rene Descartes (17th century philosopher); dualism, Mental substance and physical substance are different, Mental substances controls the physical brain.

5. Cartesian Dualism; a principle which essentially states that the mind and body are non identical. The body (and brain) are made will persist in existing, even when the material body does not. Although they do interact, the mind is independent of the body. In addition, some bodily activities are influenced by the mind and yet some are not. The theory of evolution contradicted Cartesian Dualism.. People are still searching for divide between animals and humans. Early theorists applied biological principles to behaviour and dod not have much room for culture e.g. Wilson (1975)- sociobiology; the new synthesis. Genetic determinism? Opponents commit 'naturalistic fallacy'. In contrast, evolutionary analyses on human behaviour reveal our phenotype plasticity (flexibility).

6. Out of african hypothesis; rapid colonisation of the world- demonstrates human phenotype plasticity!

7. Common Pitfalls; humans have 'stopped evolving', evolution= improvement, we have evolved 'from' monkeys. Group selection (Wynne-Edwards 1962).

8. Mate choice- Anisogamy; females- few,large,immobile gametes (eggs), male-many,small,moline gametes (sperm), poor quality offspring/ failed reproduction is more costly for females, males can afford to mate with many. Females need to spend their investment wisely.

9. Bateman's principle; because men have potential to produce more offspring, but they are listed by the number of females, there is huge variation within male reproductive success. Anisogamy + Batesman's principle = females are choosier.

10. Thus, these fundamental evolutionary principles predict that men and women will differ in their mate preferences- men; not choosy, emphasis on mating effect (but tradeoff between mating and rearing) seek polygyny, seek youth, seek fertility. Women; choose emphasis on rearing effort, seek monogamy, seek genetic quality, seek ability to provision (resources). women seek resources (well-off, professional, educated, solvent). Women week commitment (stable, dependable, family-orientated, sincere). Men seek physical attractiveness (good-looking,healthy, shapely). Traits offered reflect those sought by opposite sex. Basic principles predict that men will usually seek younger women, and women slightly older men.. Reproductive value vs access to resources. Illustrated in lonely hearts adverts (Waynforth & Dunbar 1995).

11. So are women more choosy? Women seek more traits than men in adverts (Pawlowski and Dunbar, 1999). Men are willing to date a wider range of women installed meetings (Grammar et al 2000). Review of social sciences literature (Grammar 1989); women use variety of cues when choosing mates, men tend to use attractiveness/youths as primary cue. Women rated men as more attractive when with an attractive women; mate choice copying (Waynforth, 2007).

12. Alturism; Hamiltons theory of kin selection; the more closely related we are to someone, the kinder/more generous/ more altruistic we are to them. Hamilton's Rule (Hamilton, 1964)= rB > C. R= coefficient of relatedness. B= benefit to the recipient of the altruistic act. C= cost to the actor. How can we test this? Perceived investment in others (questionnaire), actual investment in others; Wills, expenditure, experimental procedures, Actualy lack of investment; neglect of children, abuse of children, patterns of murder and infanticide. What if you are not sure who your relatives are? Men- uncertain of offspring, Women- certain of offspring--- Paternity certainty.

13. Apicella & Marlowe 2004- questionnaires study of men and their investment in their children. Plates et al. 2004; presented men and women with children cases, mopped with their own. Men said they were more likely to invest in morphed offspring than women. No different between men and on negative questions. So we know who benefits from kin selection, but who looses out? flipside of studying altruism. Daly & Wilson (1988) 'homocide'- leading figures in evolutionary approaches to violence etc Ispired by the social psychological observations that family is the most violent social group- disrupt skin selection.

14. Cheat detection- the cheat detection module; living in social groups requires cooperation... but cooperation requires the ability to detect cheaters/ free riders. Rapid mechanism would be advantageous (Cosmoses 1989). Jason selection Task (1966). Cosmoses (1989)-'chest; detection module is activated by social situation (not just familiarity- obscure rules are also understood).