Understanding Personality Traits: Extraversion and Neuroticism

1. Chapter Seven Biological Processes and Personality

2. Extraversion • Hans Eysenck—level of extraversion/ introversion reflects differences in cerebral cortex activation • IntrovertsExtraverts • Higher basal cortical activation • Lower basal cortical activation • More alert when nothing happening • Less alert when nothing happening • Withdraw to avoid overstimulation • Seek stimulation to elevate arousal • Fewer mistakes on tasks requiring • More bored by repetitive tasks vigilance • Require more depressant drugs to • Require more stimulants to reach reach given index of unalertness given level of arousal

3. Neuroticism • High neuroticism reflects easily aroused emotion centers in the brain • Emotional arousal exaggerates behavioral responses of introverts and extraverts

4. Behavioral Approach System (BAS) • Regulates movement toward desired states or objects (incentive) • Responsible for positive emotions (left prefrontal cortex) • Relates to conditioning involving positive outcomes, but not negative outcomes • People with different levels of BAS sensitivity demonstrate differences in behavioral and emotional responses to incentives • May be related to dopamine activity

5. Behavioral Inhibition System (BIS) • Regulates movement away from undesired states or objects • Associated with anxiety (right prefrontal cortex) • Relates to conditioning involving negative outcomes, but not positive outcomes • People with different levels of BIS sensitivity demonstrate differences in behavioral and emotional responses to punishment • May be related to serotonin and/or GABA activity

6. Approach/Inhibition and Traits • BIS-related neuroticism/emotionality • Anxiety at core of emotionality • High BIS-sensitive people respond to anxiety manipulations • BAS-related to extraversion • High BAS-sensitive people respond to positive mood manipulations

7. Areas of Disagreement • Social qualities of extraversion? • Perhaps it’s useful to think of social incentives as an important class of rewards to which extraverts are drawn in order to experience positive affect • Role of impulsivity • Is it linked to extraversion? • Is it a separate trait (the flip-side of conscientiousness)? • Another view—impulsivity with positive affect belongs with extraversion • Impulsivity items do not load with BAS or extraversion items in a factor analysis

8. Sensation Seeking • Marvin Zuckerman • High sensation seekers are in search of new, varied, and exciting experiences • Drive faster • More likely to use drugs and increase alcohol use over time • More high-risk sports • More risky antisocial behavior • More sexually experienced and responsive • More dissatisfied with relationships • Monoamine Oxidase (MAO) • Related to levels of sensation seeking • Also associated with social dominance, aggression, and gene linked to impulsivity

9. Function of Sensation Seeking • Regulates exposure to stimulus intensity • High sensation seekers (HSS) open themselves up to stimulation • HSS do well in overstimulating conditions • Low sensation seekers (LSS) adapt better to most ordinary circumstances, but may shut down under intense conditions • Impulsive unsocialized sensation seeking (IUSS) —inability to inhibit behavior appropriate to social constraints

10. Impulsiveness • Issue: How best to account for impulsiveness • Approach and inhibition systems • High BAS • Low BIS • Combination (high BAS and low BIS) • Serotonin • Most studies relate serotonin to negative emotion • Low serotonin function associated with anger, impulsive aggression • Serotonin levels positively related to conscientiousness • Suggestive that impulsiveness derives from a separate biological system

11. Hormones and Personality • Testosterone: • Higher prenatal levels weeks 8-24, months 1-5 after birth, and after puberty for normal males • Developmental default is female • Exposure to androgens results in male physical and neurological development • Exposure to higher levels of prenatal androgens: • Associated with higher self-reported physical aggression scores in response to hypothetical situation (boys and girls) • Associated with cross-gender toy selection among girls

12. Testosterone and Adult Personality • Focus on associations with dominance and antisocial behavior • Positive associations with: • Violation of prison rules among inmates and likelihood of having committed violent crime • Veterans’ trouble with parents, teachers, and classmates when growing up (increased effects among low SES) • Being a trial lawyer, actor, NFL football player • More dominant and confident social interactions • Not being married, getting divorced, having an affair, and domestic abuse among men • Factor analysis with personality items—testosterone data loaded with impulsiveness, sensation seeking, and dominance

13. Cycles of Testosterone Action • Testosterone rises after: • Success in a competitive event • Your team wins • Sexual intercourse • Challenged by insult • Testosterone falls after: • Failure or humiliation • Your team loses

14. Testosterone, Dominance, and Evolutionary Psychology • Males: Overt aggressiveness helps confer dominance and status increasing reproductive advantage • Females: No advantage for aggressiveness in females and may interfere with reproductive success and child rearing activities • Irony: In today’s society, dominance and status are defined in greater socioeconomic terms. High levels of testosterone may interfere with socioeconomic advancement

15. Men, Women, and Oxytocin • In response to threat, animals engage “fight or flight” response • Most research demonstrating this effect was done with males • Different response may be activated for females—“tend and befriend” • Reflects differing evolutionary pressures on males and females due to offspring investment (i.e., not effective to fight when pregnant or caring for an infant) • Derived from systems that produce bonding between infant and caregiver • Oxytocin—hormone resulting in relaxation, calming, mother-infant bonding, general social bonding, and adult pair-bonding in some species • Females typically have higher levels than men • Androgens inhibit release of oxytocin under stress; estrogens activate release • Released during orgasm, childbirth, massage, and breast-feeding

16. Assessment • Assessment tied to biological processes • EEG—measures of electrical brain activity • PET—mapping of brain activity from metabolic function • MRI—images of brain function from magnetic fields created from neural activity • Functional MRI—assesses levels of activation at rest and during mental activity

17. Problems in Behavior • Anxiety—indicative of oversensitive BIS activity • Depression • High BIS activity • Weak BAS activity • Antisocial personality • High BAS activity • Low BIS activity • Third system—sensation seeking, low MAO, high testosterone

18. Therapy • Modifying biological function may change manifestation of disorders • Pharmacotherapy—drug administration • Antianxiety drugs • Antidepressants (SSRIs) • If drug therapy changes personalities, what are the implications for the way we view the construct?