Download Evolutionary Forces on personality

Evolutionary Forces on personality
Sociobiology = the study of biological bases of social
behavior
**psychological qualities have been retained in people
over many years because they are adaptive
3 important points:
1.
2.
3.
Reproductive success
Adaptive value pertains to early life
Adaptive value in terms of specific tasks in specific situations
What psychological mechanisms
have evolved?
Male/female mate preferences
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Females will have stronger preferences
Females focus on mates’ ability to provide
resources
Males focus on reproductive potential
Sex objects vs. success objects
Evolutionary theory and attraction
Genetic similarity theory (Rushton, 1989; Rushton, Russell & Wells, 1984):
• more attracted to strangers who resemble you than who don’t
• leads to offspring with not only your genes but genes like
themselves
• Rushton’s research shows that people are more attracted to
genetically similar people
• People who go on to have children together are more alike than
those who don’t. Thus among sexually active couples, those most
genetically similar are those most likely to have reproduced.
• Attraction not limited to the opposite sex. We tend to be friends
with people who are genetically similar. Why? From an evolutionary
perspective it’s because you are more likely to be altruistic to a
friend than a stranger, making it more likely that the friend will go
onto reproduce (similar genes to your own) and you may n\meet
the friend’s opposite sex sibling - close genes again!
• How do we detect this genetic similarity: either drawn to those with
similar facial and bodily features OR via smell.
Please think of a serious committed relationship
you have had in the past, that you currently have,
or that you would like to have. Imagine that the
person with whom you’ve become seriously
involved became interested in someone else. What
would distress or upset you more?
– (a) Imagining your partner forming a deep emotional
attachment to that person OR
– (b) Imagining your partner enjoying passionate
sexual intercourse with that person
Sexual/relationship jealousy
Based on evolutionary forces, men and women approach
sexual jealousy differently
Buss, Larsen, Westen, and Semmelroth (1992) men and
women were asked to respond to the previous vignette:
FEMALES = 82% option (a) 18% option (b)
MALES = 40% option (a); 60% option (b)
Males jealous of sexual fidelity
Females jealous of emotional fidelity
Brain function and personality
1. Behavioral approach system (BAS)
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Incentives
Left frontal lobe
dopamine
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withdrawal
Right frontal lobe
Serotonin?
Anxiety/cues of threat
2. Behavioral inhibition system (BIS)
BAS and BIS act independently
Link to temperament
1. BIS sensitivity and emotional
instability/neuroticism
2. BAS sensitivity related to extraversion
3. Role of impulsivity
4. Zuckerman – sensation seeking
Role of hormones
Sex hormones important:
• weeks 8 – 24 prenatally, in months 1-5 after birth,
and after puberty
• changes to nervous system
Link to behavior in children
Reinisch, 1981
sex difference
effect of prenatal exposure
filter by cognitions
Hormonal links to behavior in
children continued
Berenbaum & Hines (1992)
1. Androgen exposed girls played with boys’
toys
2. No difference in boys
Jacklin, Maccoby, & Doering (1983)
1. Boldness or timidity of infant boys
2. No effect for girls
• Testosterone and adult personality