1. Biology & Personality

2. Phineas Gage video Early evidence of brain & temperament
Brain injury changed disposition
Role of body & brain in consistencies of behavior?
Extraverted bodies?
Emotionally (un)stable brains?

3. Outline Temperament Evolution and personality Behavioral genetics
Brain and temperament

4. Temperament Individual differences in affective response Inherited
Biologically based
Evidence from birth & stable throughout life
NOT traits but related
Traits not stable from birth & less pervasive influence

5. Temperament Early views linked T w/ body features Gall & phrenology
Kretschmer, Sheldon & body types
Inherited body determines T
Direction of effect problem
Recent work finds that endo NOT jolly

6. Temperament: Recent Research
New York Longitudinal Study (Thomas & Chess, 1977)
Kids followed from birth (1950) - adolescence
Parental reports revealed easy, difficult, & slow-to-warm-up babies
Associated w/ later adjustment

7. Temperament: Recent Research
Kagan (1999): Inhibited v. uninhibited kids
Laboratory observations of 4 month olds revealed high & low reactivity
Stability of T at 4/8 years old
Change also due to parental influence

8. Temperament: Recent Research
In sum temperament construct supported
Link between biology & personality
Reciprocally causal
Temperaments linked w/ Big-5 (guide trait development)
Emotionality (~N)
Activity (~E)
Sociability (~E)

9. Jealousy On a clean sheet of paper answer this Q:
What would bother you more: Your boy/girl friend (spouse) having sex with someone else or developing emotional feelings for someone else?
Sexual or emotional infidelity?
What is your gender?

10. Evolutionary Theory Characteristics associated w/ survival selected
Ultimate causes of current behavior tendencies
Evolved psychological mechanisms (specific)
Nature of human nature (e.g., social)
Individual differences
Directional v. stabilizing selection
Niches

12. Activity 9: Gender Differences
Provide a critical analysis of the research examining evolutionary predictions regarding gender differences in mate preferences & jealousy.
Does the evidence support these claims?
Can you think of any alternative explanations?
PLEASE TURN THIS IN AFTER CLASS!

13. Gender Differences Problems w/ evidence for evolutionary account
1. Failures to replicate
Some studies find most men choose emotional infidelity
No gender differences in physiology
2. All forced choice methodology
No gender difference w other methods

14. Gender Differences
Harris (2002)
Forced choice
M > W on sexual

15. Gender Differences Harris (2002) Recalled episode of infidelity
No gender effects
Both more bothered by emotional

16. Gender Differences 3. Cultural/social theories: Similar predictions
Social Exchange Theory
Men control resources, women control sex
Women give sex to men in exchange for resources
Women most upset about losing resources (love = shifting loyalties) & choose resource-rich mate
Men most upset about losing sex & choose sexy mate

17. Day 2

18. Behavioral Genetics Examine contribution of nature & nurture
Twin & adoption studies
Heritability coefficient (h2)
Findings: h2s ~ .40
Specific to population
Not fate
Not single genes
“Bummer of a Birthmark Hal”

19. Shared & Non-Shared Environment
Variability in characteristics in population
40% genetic
40% environment (+ 20% error)
Shared (same family, house, etc.): 5%
Non-shared (unique experiences, including perceived even w/in same family): 35%

20. Shared & Non-Shared Environment
Similar environments have little impact
Similar experiences do not -> personalities more alike
Genes make us similar
Non-shared environment makes us different

21. Reaction Paper 7: Rearing Influences
How much variability in personality is due to shared environmental influences? Does this suggest that rearing practices & parents are not important in personality development? Was Dan Quail wrong in saying single parent homes are bad for the children?

22. Neuroscience & Personality
Where in the brain is personality?
Specific areas & systems show individual differences

23. Amygdala Motivation & emotion Damage impairs NA Rs
Arousability linked w/ T
Metabolically linked w/ N

24. Amygdala Neurotics have rapid amygdalar metabolism
Impair NA repair, decay
Explain NA of neurotics?
Irwin et al (2000)

25. Ascending Reticular Activation Formation (ARAS)
Located w/in brain stem & controls arousal
Individual differences in reactivity
Extraversion due to reactivity of ARAS
Baseline higher among I
Response to stimulation stronger among I

26. Extraversion and ARAS arousal

27. Optimal Arousal Comfortable functioning
Es under-aroused & should prefer high stimulation activities
Is over-aroused & should prefer low stimulation activities
Stimulus shy (I) or Stimulus hungry (E)

28. Evidence Task choice Physiological arousal Task performance
E choose higher stimulating behavior than I
Physiological arousal
I > E for given level of stimulation
Task performance
Is do better at monotonous jobs (air traffic) & moderate levels of stimulation
Es do better at fast paced jobs & higher levels of stimulation

29. Approach & Inhibition Systems
2 Brain system involved with:
Approach behaviors & positive emotions
Inhibit behaviors & negative emotions
Key are individual differences in the reactivity of these brain systems

30. Behavioral Approach System (BAS)
Structures in left Pre Frontal Cortex (PFC)
Cause approach behavior (GO!) during incentives
Controls positive emotions
Individual differences in reactivity (hi lo)
Associated w/ E & uninhibited T

31. Behavioral Inhibition System (BIS)
Structures in right Pre Frontal Cortex (PFC)
Cause avoidance/inhibitory behavior (Stop/Reverse!)
Activated during punishment/danger/threat
Controls negative emotions regarding punishment
Individual differences in reactivity (hi lo)
Associated w/ N & inhibited T

32. BAS/BIS Measurement EEG activity Self-Report Measures
High baseline (left or right PFC) & strong response to positive or negative stimuli
Self-Report Measures
Reward or Punishment sensitivities, seek/avoid
When I get something I want I feel excited & energized
Criticism or scolding hurts me quite a bit
Correlated w/ PFC activity

33. BAS & BIS Independent dimensions Individual differences on both
All combinations possible
These combos are key for understanding personality
BIS

34. Neurotransmitters BAS, PE associated w/ dopamine
Genes producing dopamine & dopamine reactivity linked to self-reported BAS
BIS, NE associated w/ serotonin
Genetic evidence mixed