Psych 205 1st Edition Lecture 15 Outline of Last Lecture I. The Biological ApproachOutline of Current Lecture II. Heritability of personality traitsIII. Extraversion-introversionIV. Evolutionary personality theory and mate selectionCurrent LectureIn todays lecture, we talked a little bit more about chapter 10 and the findings from twin studies. We also talked about the heritability of personality traits, extraversion, introversion andalso the evolutionary personality theory and mate selection.The Biological Approach (Continued) -Findings from twin studies-Identical MZ twins are more similar than fraternal DZ has concluded that about 40% of the stability in our adult personalities is due to what we inherit from our parents-Research from adoption studies suggests it is only about 20%-Combined twin0adoption studies find MZ twins more similar whether they wereraised together or apart from their twinsWhy are twin study findings of heritability higher than adoption study findings?-Twin study researchers make two key assumptionsAssumption 1These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Twin pairs can be accurately identified as MZ or DZ twinsAssumption 2MZ and DZ twins have equally similar environments-Not accurate assumption to make-Identical twins may be treated more alike than are DZ twins-Environmental influence on personality traits may not be similar environments-Not an accurate assumption-Identical twins may be treated more alike than are DZ twins-Environmental influence on personality traits may not be as similar for DZ twins as it is for MZ twinsAdoptions are “random”-Typically, they are not random-Children are placed in homes similar to their previous homes-Parents will treat all their children the same-They may have different expectations for their sorted childrenInterpreting the heritability findings-Taken together, differences inn findings likely due in part to differences in methods used-Nonadditive effects-Rarely is one gene responsible for one trait-Genetic influence of some personality traits may not be seen unless a unique combination of more than one gene is inherited-MZ twins hare all their genes, meaning they also hare all the combinations of their genesHeritability of extraversion-Large-scale twin studies-12,898 twin pairs in Sweden-7,144 twin pairs in Finland-Results provide strong evidence for genetic component to extraversion-introversion-Even though MZ twins more likely to stay in touch, this alone did not account for difference in findingsHeritability of extraversion-In sum, extraversion-introversion has one of the strongest genetic components of any personality variable-Where you fall on that line was likely determined long ago-Inherited differences Extraversion and preferred arousal level-Researchers asked students studying in two kinds of library sections to completean extraversion inventory-Students in the noisy, open area tended to be extraverts-they find the quiet boring-Students in isolated, quiet places tended to be introverts-more sensitive to stimulation-Research outcomes from lab experiments-Extraverts quicker to change visual stimuli-Extraverts show drop in performance when pace of task slows down-Introverts set volume at lower levels-Findings are entirely consistent with the descriptions of extraversion-introversionExtraversion and happiness-Possible reasons extraverts experience more happiness-Extraverts socialize more than introverts-Social contact associated with better well-being-Friends buffer against stress -are sensitive to rewards So should everyone try to be an extravert?-Extraverts are more social, but they also tend to be more impulsive-This can create problems in work, relationships and other aspects of life-Introverts avoid potential lapses in judgment evolutionary personality theory and mate selection gender differences in self-descriptions-Research suggests that women tend to describe themselves as physically attractive-From the evolutionary point of view: men and women select their mates based in part on what serves the needs of the species-The is: ONE theory about mate selection that is arguably limited by: focus on male-female relationships only and emphasis on “traditional” gender roles-Choosing partners is based on concerns for parental investment need to pass on genes-Select mates likely to be part of successful reproduction and effective child rearing-Certain mate selection preferences have been passed down through generations-Men and women have different ideas about parental investment-Investment in selecting a mate is larger for women than for men in evolutionary terms-Women in many cases raise offspring-Males in some species may focus more on passing along their genesHigh productive value-Younger in age but a focus on fertility-teenage boys reported preference for slightly older women-Physical features that suggests fertility and happen to be associated with attractivenessWhat does the research say?-National survey of unmarried American adults-Men preferred younger women-Intersexual selection-competition among members of one gender for mating access to the best members of the other gender-Women likely to report using methods of enhancing attractiveness too secure partner-“Lipstick effect”- women spend more money on cosmetics during times of economic downturnWhat did women look for in men?-Providers-Ability to care and nurture and transfer power to sons or daughters-Dominant and generousWhat does the research say?-Women in one study emphasized characteristics like dependable, ambitious, and career-oriented-More willing to give up physical ambitions-Cross-cultural findings-37 cultural groups surveyed (33 countries, 6 continents)Conclusions and limitations-Research findings on preferences of men and women are consistent with the prediction from evolutionary personality psychology-Need to exercise caution when interpreting these findings-Correlation, not causation-Example: differences in maturity level-Findings are not always consistent with evolutionary personality theory-If these findings were true, men and women should have different reactions to infidelity-Possibility exists that instincts inherited form the ancestors are overshadowed by preferences-What we see “in the wild” may not apply to us-Men and women both rated mutual love and affection as most important in one study-Gender