Biological Processes and Personality Chapter Seven Biological Processes and Personality

Extraversion Hans Eysenck—level of extraversion/ introversion reflects differences in cerebral cortex activation Introverts Extraverts 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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?