Psychology 3051 Psychology 305A: Theories of Personality Lecture 6 1

A.D.H.D. Attention Detours on a Highway Drive Student Directed Seminar Term 2: ASTU 400A Mondays 4pm – 7pm Graduate seminar format - Lead a class, dive deeper - Feedback on presentation, content analysis and discussion Successfully manage everyday difficulties - Practical knowledge to use or share (while earning credit) - Knowledge breadth and depth Challenge your current paradigm - Empirical research (implications of knowledge, effect on society, personal impact) - Increase awareness of stigma, personal accountability and social responsibility Application Required!

3 Announcement Students who wish to obtain more information regarding Psychology 417A: Psychology and Developing Societies may attend a course-specific information session at the Go Global Showcase. Date: Wednesday, October 3, 2012 Time: 4:30-5:15pm Location: Irving K. Barber, room 302 (Dodson Room)

Psychology What are the basic principles of evolutionary theory? 2.How have the basic principles of evolutionary theory been adapted to the study of personality? 3. What hypotheses has the evolutionary approach generated regarding (a) altruism, (b) sex differences in the desire for sexual variety, and (c) sex differences in jealousy? The Biological Perspective 4

By the end of today’s class, you should be able to: 1. describe natural selection, sexual selection, intrasexual selection, and intersexual selection. 2. generate examples of distinct forms of selection define the term “inclusive fitness.” 4. review research supporting evolutionary hypotheses related to altruism. 5

6 5. define the terms “reproductive capacity” and “minimal parental investment.” 6. review research supporting evolutionary hypotheses related to sex differences in the desire for sexual variety and jealousy. 6

Psychology 3057 What are the basic principles of evolutionary theory? According to Darwin’s theory of evolution, across successive generations of a species, organisms develop characteristics that enhance their ability to survive and reproduce (i.e., adaptations). Darwin maintained that there are two processes through which organisms develop these characteristics: 7

Psychology Natural selection  A process through which organisms develop characteristics that enhance their ability to survive.  Organisms that possess characteristics that enhance their ability to survive are more likely to live to reproductive age and to pass these characteristics on to the next generation. 8

Psychology 3059  Through this process, characteristics that enhance the organism’s ability to survive increase in frequency across successive generations of the species until they characterize virtually all members of the species.  Offspring that inherit these characteristics, in turn, are more likely to live to reproductive age and to pass the characteristics on to yet the next generation. 9

 Example: The preference for sweet, fatty, and salty foods among humans. 10

Psychology Sexual selection  A process through which organisms develop characteristics that enhance their ability to reproduce. 11  Darwin maintained that there are 2 mechanisms through which sexual selection occurs:

Psychology (a) Intrasexual selection  Occurs when same sex organisms compete for the sexual interest of the opposite sex.  Organisms that possess characteristics that enable them to “win” the sexual interest of the opposite sex are more likely to mate and to pass these characteristics on to the next generation. 12

Psychology  Offspring that inherit these characteristics, in turn, are more likely to mate and to pass the characteristics on to yet the next generation.  Through this process, the characteristics that enabled the victors to win increase in frequency across successive generations of the species until they characterize virtually all members of that sex of the species. 13

 Example: The Ariel Hover Display of the male Bronzed Cowbird. 14

Psychology (b) Intersexual selection  Occurs when organisms of one sex prefer to mate with organisms of the opposite sex that possess specific, desirable characteristics.  Organisms that possess characteristics that are desirable to the opposite sex are more likely to mate and to pass these characteristics on to the next generation. 15

Psychology  Offspring that inherit these characteristics, in turn, are more likely to mate and to pass the characteristics on to yet the next generation.  Through this process, characteristics that are desirable to the opposite sex increase in frequency across successive generations of the species until they characterize virtually all members of that sex of the species. 16

 Example: The brilliant plumage of the male peacock. 17

Psychology How have the basic principles of evolutionary theory been adapted to the study of personality? Evolutionary psychologists believe that our basic psychological processes are the product of natural selection and sexual selection. Our psychological processes are seen as adaptations to the survival and reproductive challenges faced by our ancestors. 18

Psychology What hypotheses has the evolutionary approach generated regarding altruism? Altruism: Refers to a desire to help others, even at the risk of one’s own well-being. Theory of inclusive fitness: Organisms are motivated to enhance their own survival and reproductive potential, as well as the survival and reproductive potential of those who are genetically similar to them. 19

Psychology On the basis of this theory, evolutionary psychologists generated two hypotheses regarding altruism.  Hypothesis B: Helping behaviour increases as the reproductive potential of one’s kin member (i.e., relative) increases.  Hypothesis A: Helping behaviour increases as the degree of genetic overlap increases between the helper and the recipient. 20

Psychology Burnstein et al. (1994) tested both hypotheses in the U.S. and Japan.  Asked participants to imagine that people were asleep in a rapidly burning building.  Told participants they could only rescue one person.  Asked participants to indicate who they would be most willing to save. 21

Psychology Tendency to Help Degree of Genetic Overlap Highly Related Not Related      Results consistent with Hypothesis A. 22

Psychology Tendency to Help Age of Kin (Years)       Results consistent with Hypothesis B. 23

Psychology Tendency to Help Degree of Genetic Overlap Highly Related Not Highly Related     Results consistent with Hypothesis B.    Healthy Sick 24

Psychology What hypotheses has the evolutionary approach generated regarding sex differences in the desire for sexual variety? Females and males differ in their reproductive capacity and the minimal parental investment that is required to produce an offspring. 25

Psychology Reproductive capacity: Males > Females  Males: Can bear an almost unlimited number of offspring across the lifespan (maximum recorded to date: 900).  Females: Can bear 8 – 12 offspring across the lifespan. 26

Psychology Minimal parental investment: Females > Males  Females: Carry and nourish fetus for 9 months; nurse child after birth; during lactation, ovulation is suppressed.  Males: Engage in copulation. 27

Psychology Given sex differences in reproductive capacity and minimal parental investment, evolutionary psychologists maintain that males and females have developed different strategies to maximize their reproductive potential. 28

Psychology Males: Employ strategies that enable them to copulate with as many females as possible. Females: Employ strategies that restrict copulation to males who are able to provide care and resources for the offspring. 29

Psychology Following from these strategies, evolutionary psychologists have generated 2 interrelated hypotheses regarding sex differences in the desire for sexual variety:  Hypothesis A: Males are less discriminating in their selection of sexual partners than females.  Hypothesis B: Males are inclined to seek more sexual partners than females. 30

Psychology Studies that have tested these hypotheses include:  Clark and Hatfield (1984)  Had confederates approach students of the opposite sex on campus.  After saying “Hi, I’ve been noticing you around campus lately and I find you very attractive,” the confederates asked the students 1 of 3 questions: 31

Psychology “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?” Percent Who Agreed Male Female

Psychology  Buss and Schmitt (1993)  Asked unmarried participants how many sex partners they would like to have through to the end of their lives.  These results are consistent with Hypothesis A. 33

Psychology Desired Number of Partners Time (Years) Life         Females          Males  Results consistent with Hypothesis B. 34

Psychology  In a large-scale cross-cultural investigation, Schmitt et al. (2003) found similar sex differences across 52 nations (e.g., Argentina, Austria, Canada, Chile, Croatia, Greece, Israel, Italy, Japan, Lebanon, Slovakia, Zimbabwe, US). 35

Psychology What hypotheses has the evolutionary approach generated regarding sex differences in jealousy? Evolutionary psychologists maintain that, once a mate has been selected with whom to copulate, males and females encounter different adaptive problems. 36

Psychology  Males: Must ensure that their mates do not copulate with other males, as this would result in uncertainty regarding the paternity of offspring.  Females: Must ensure that their mates do not withdraw care and resources, as this would jeopardize the survival of offspring. 37

Psychology Following from these adaptive problems, evolutionary psychologists have generated 2 interrelated hypotheses regarding sex differences in jealousy:  Hypothesis B: Males are more likely than females to become jealous in response to cues that suggest sexual infidelity.  Hypothesis A: Females are more likely than males to become jealous in response to cues that suggest emotional infidelity. 38

Psychology Studies that have tested these hypotheses include:  Buss et al. (1992; see also Buunk et al., 1996; Miller & Maner, 2009; Schutzwohl & Kock, 2004):  Presented participants with the following dilemma: 39

Psychology Think of a serious, committed romantic relationship that you had in the past, that you currently have, or that you would like to have. Imagine that you discover that the person with whom you’ve been seriously involved has become interested in someone else. Of the following, what would distress or upset you more? 1. Imagining your partner forming a deep emotional attachment to that person. 2. Imagining your partner enjoying passionate sexual intercourse with that other person. 40

Psychology Percentage Reporting More Distress to Sexual Infidelity  Results consistent with Hypotheses A and B. 41

Psychology What are the basic principles of evolutionary theory? 2.How have the basic principles of evolutionary theory been adapted to the study of personality? 3. What hypotheses has the evolutionary approach generated regarding (a) altruism, (b) sex differences in the desire for sexual variety, and (c) sex differences in jealousy? The Biological Perspective 42