Lecture 8.docx

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Lecture 8 (ch.8) In today’s class… - Evolutionary Theory - Evolutionary Psychology - Making & testing predictions about Personality from Evolutionary Psychology From the text… - Describe the key features of evolution by natural selection. - Discuss the premises and limitations of Evolutionary Psychology - How do Evolutionary Psychologists approach the study of Personality? - What do we know about human behaviour? (i.e. aggression, jealously, Big 5, mate preferences, etc.) Natural Selection & Reproductive Success - Natural Selection • naturally occurring variation leads to differences in the ability to survive and reproduce (reproductive success) • the next generation contains more of the successful variant. - Darwin’s Finches – specific beak features that make it easier for each bird to do the task or go after the food they eat – adaptive Sexual Selection - Darwin’s solution - Certain characteristics make it easier for mate selection - Two forms of sexual selection • Intrasexual competition: Members of the same sex compete with each other for sexual access to members of the other sex  Ex: moose, the males compete with each other to win the female • Intersexual competition: Members of one sex choose a mate based on their preferences for particular qualities in that mate  One gender is attracted to the characteristics of the other gender  Ex: female peacocks are attracted to the bright/healthy colors of the male - Differences between species and within species Products of the Evolutionary Process - Adaptations - Byproducts ofAdaptations • Ex: nose, belly button, bones. Not really adaptive, but have features • Length of ring finger compared to pointer finger – longer ring finger = more testosterone - Noise or Random Variation • Noise: ear lobes. Don’t really do anything, but there are differences between people Evolutionary Psychology and Human Nature - Over evolutionary time, successful mechanisms spread through population and come to characterize all humans - Examples of evolutionary analysis at the level of human nature • The Need to Belong • Helping and Altruism • Universal Emotions • Sex Differences and Mating Behavior Sex Differences - Evolutionary psychologists expect that males and females will be the same or similar in all domains where sexes have faced the same or similar adaptive problems - Expect sex differences in those domains where sexes recurrently faced different adaptive problems Shackelford, Buss & Bennett (2002) - Imagine that you discover that the person with whom you’ve been seriously involved became interested in someone else. - With this in mind, chooseAor B for each of the following. - Women know a child is theirs because it’s in them, men don’t know if a child is theirs for sure, so get more jealous over sexual infidelity than emotional infidelity - Still variation, some men said emotion and some women said sex, but overall men get more jealous over sexual infidelity and women get more jealous over emotional infidelity Sex Differences - Examples of differences between men and women that are attributable to recurrently facing different adaptive problems • Sex Differences in Aggression • Sex Differences in Jealousy • Sex Differences in Desire for Sexual Variety • Sex Differences in Mate Preferences - In areas where you have the same challenges, men and women should be similar, but in areas where they have different challenges, men and women will be different – ex. carrying a baby Sex Differences - Jealousy • Men over evolutionary history have risked investing in children who were not their own • Men should be more jealous in response to cues to a sexual infidelity • Women should become more distressed over a partner’s emotional infidelity - Men are generally more aggressive than women - What makes men versus women jealous is different - Differences in mate preferences • Men like attractiveness / youthfulness • Women like masculinity and high achievement Shackelford, Buss & Bennett (2002) - Results: • Men, relative to women, find it more difficult to forgive a sexual infidelity than an emotional infidelity • Men, relative to women, are more likely to terminate a current relationship following a partner’s sexual infidelity than an emotional infidelity - Percentage of sample that agreed that a partner’s sexual infidelity was more upsetting than an emotional infidelity… • Males: 61.9 % • Females: 22.0 % - Making sense of these results • Agreater percentage of males than females expressed jealously toward a sexual infidelity. • 61.9% of males and 78% of females were consistent with the hypothesis – but 38.1% of males and 22% of females were inconsistent. - Percentage of sample that agreed that imagining a partner trying different sexual positions with another person was more upsetting than imagining a partner falling in love with another person… • Males: 49.6 % • Females: 11.8 % - Percentage of sample that found it more difficult to forgive a sexual infidelity than an emotional infidelity… • Males: 65.1 % • Females: 52 % - Conclusion – evidence that evolutionary processes have had an impact on gender differences in jealously. - However, genetics did not entirely control behavior – there were still individuals who did not fit the prediction – and we, as individuals, have the capacity to choose our behavior (we are not mindless genetic robots) - Women know a child is theirs because it’s in them, men don’t know if a child is theirs for sure, so get more jealous over sexual infidelity than emotional infidelity - Still variation, some men said emotion and some women said sex, but overall men get more jealous over sexual infidelity and women get more jealous over emotional infidelity Desire for Sexual Variety - Clark & Hatfield (1989) - Members of the sex that invests less in offspring, are predicted to be less discriminating in their selection of mates & more inclined to seek out multiple mates - Evolutionary theory predicts men are more inclined to seek multiple mates to increase their reproductive success - To counteract for safety concerns, they started using close friends instead of strangers Desire for Sexual Variety Clark & Hatfield - Students approached by a stranger and asked one of three questions: • “would you go out on a date with me tonight?” • “would you go back to my apartment with me tonight?” • “would you have sex with me tonight?” - Would you predict a gender difference in response patterns? - Problem – what if the differences are the result of women’s concerns for safety? - Study 2 – male & female participants were contacted by a close personal friend • Participant testified to the integrity of the “asker”  “would you be willing to go on a date?”  “would you be willing to go to bed with me?” • Results? Clark & Hatfield (1989) – Results Study 1 Male pps Female pps 50% date 55% 69% apt? 6% 75% sex? 0% Study 2 Male pps Female pps