Chapter 7 Physiological Approaches to Personality 2014 Mc

+ Chapter 7 Physiological Approaches to Personality © 2014 Mc. Graw-Hill Higher Education. All rights reserved.

+ Physiological Measures Commonly Used in Personality Research n Electrodermal Activity (Skin Conductance) n Cardiovascular activity n Brain Activity n Other measures: n Biochemical analyses of blood and saliva © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -2

+ Electrodermal Activity (EDA): Skin Conductance n Most obtained by electrodes or sensors placed on the skin surface n Advantage: n n Noninvasive, no discomfort Disadvantage: n Movement constrained © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -3

+ Electrodermal Activity (EDA): Skin Conductance n Electrodermal activity—due to increased sweat with arousal, skin conductance of electricity increases n Can measure responses to various stimuli, including sudden noises, emotionally charged pictures, pain, anxiety, fear, guilt n Some people show EDA in the absence of external stimuli— associated with anxiety and neuroticism © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -4

+ Cardiovascular activity n Blood pressure n n Measure of, e. g. , stress reactivity Heart rate n Increases with anxiety, fear, arousal, cognitive effort © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -5

+ Cardiovascular activity n Cardiac reactivity n Greater than normal increase in blood pressure and heart rate when performing task such as backward serial subtraction n Associated with Type A personality—impatience, competitiveness, hostility n Cardiac reactivity (and Type A) associated with coronary heart disease © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -6

+ Brain Activity n Brain spontaneously produces small amounts of electrical activity n Can be measured by electrodes on scalp— electroencephalograph (EEG) n Evoked potential technique—uses EEG, but the participant is given a stimulus and the researcher assess specific brain response to stimulus © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -7

+ Brain Activity n Brain imaging techniques—map structure and function of brain n Positron emission tomography (PET) n Functional magnetic resonance imaging (f. MRI) © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -8

+ Physiologically Based Theories of Personality n Extraversion-Introversion n Sensitivity to Reward and Punishment n Sensation Seeking n Neurotransmitters and Personality n Morningness-Eveningness n Brain Asymmetry and Affective Style © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -9

+ Extraversion-Introversion n Measured by Eysenck Personality Questionnaire (EPQ) n High extraversion: n n Talkative, outgoing, likes meeting new people and going to new places, active, bored easily, hates routine Low extraversion: n Quiet, withdrawn, prefers being alone or with a few friends to large crowds, prefers routines, prefers familiar to unexpected © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -10

+ Extraversion-Introversion n Eysenck’s theory n Introverts have a higher level than extraverts of activity in the brain’s ascending reticular activating system (ARAS) n People strive to keep ARAS activity at optimal level—introverts work to decrease and avoid stimulation; extraverts work to increase and seek out stimulation n Research indicates that introverts and extraverts are NOT at different resting levels, but introverts ARE more reactive to moderate levels of stimulation than extraverts n This work led Eysenck to revise his theory—the difference between introverts and extraverts lies in arousability, not in baseline arousal © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -11

+ Extraversion-Introversion n Eysenck’s theory n When given a choice, extraverts prefer higher levels of stimulation than introverts n Geen (1984): n Introverts and extraverts choose different levels of stimulation, but equivalent in arousal under chosen stimulation n Introverts and extraverts perform task best under their chosen stimulation level, poor when performing under a stimulation level chosen by other group © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -12

+ Sensitivity to Reward and Punishment n Personality based on two hypothesized brain systems n Behavioral Activation System (BAS): n n Responsive to incentives (cues to reward) and regulates approach behavior Behavioral Inhibition System (BIS): n Responsive to cues to punishment, frustration, uncertainty, and motivates ceasing, inhibiting, or avoidance behavior n Active BIS produces anxiety, active BAS produces impulsivity © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -13

+ Sensitivity to Reward and Punishment n Integration with Eysenck’s model: n Impulsive = high extraversion, moderate neuroticism n Anxious = moderate introversion, high neuroticism n According to Gray, impulsive people do not learn well from punishment because of weak BIS; learn better from reward— supported by research © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -14

+ Sensation Seeking n Tendency to seek out thrilling, exciting activities, take risks, avoid boredom n Early sensory deprivation research n Hebb’s theory of optimal level of arousal © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -15

+ Sensation Seeking n Zuckerman: n High sensation seekers are less tolerant of sensory deprivation n Require much stimulation to get to optimal level of arousal n Zuckerman’s Sensation Seeking Scale n Moderate positive correlation between extraversion and sensation seeking © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -16

+ Sensation Seeking n Physiological basis for sensation seeking n Neurotransmitters n n Chemicals in nerve cells are responsible for the transmission of nerve impulse from one cell to another Monoamine Oxidase (MAO) n Enzyme that maintains a proper level of neurotransmitters © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -17

+ Sensation Seeking n Physiological basis for sensation seeking n Too little MAO = too much neurotransmitter n Too much MAO = too little neurotransmitter n High sensation seekers have low levels of MAO, producing a need for stimulation to reach the optimal level of arousal © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -18

+ Neurotransmitters and Personality n Dopamine n n Serotonin n n Associated with pleasure Associated with depression and other mood disorders Norepinepherine n Associated with fight or flight response © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -19

+ Neurotransmitters and Personality n Cloninger’s Tridimensional Personality Model n Novelty seeking n n Harm avoidance n n Low levels of dopamine Low levels of serotonin Reward dependence n Low levels of norephinepherine © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -20

+ Morningness-Eveningness n Being a “morning-type” or “evening-type” of person is a stable characteristic n Due to differences in underlying biological rhythms n Many biological processes fluctuate around a 24 -25 hour cycle —circadian rhythm; e. g. , body temperature, endocrine secretion rates n But wide individual differences are in the circadian rhythm, identified through temporal isolation studies © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -21

+ Morningness-Eveningness n Individuals with shorter circadian rhythms hit peak body temperature and alertness earlier in day, get sleepy earlier, than individuals with longer rhythm n Individuals with shorter rhythm tend to be morning persons n Individuals with longer rhythms tend to be evening persons n Morningness-Eveningness Questionnaire n Cross-cultural replication and documentation of stability of characteristic © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -22

+ Brain Asymmetry and Affective Style n Left and right sides of the brain are specialized, with asymmetry in control of psychological functions n Using EEG, can measure brain waves, such as alpha wave— an inverse indicator of brain activity n Left frontal hemisphere is more active than the right when a person is experiencing pleasant emotions; right is more active than left with unpleasant emotions n Patterns replicated in adults, children, and infants © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -23

+ Brain Asymmetry and Affective Style n Research indicates that the tendency to exhibit asymmetry (favoring left over right, or right over left activation) is a stable individual characteristic n Dispositionally positive persons show greater left frontal EEG activity n Dispositionally negative persons show greater right frontal EEG activity n Conclusion: n Person’s affective lifestyle may have origins in, or be predicted by a pattern of asymmetry in frontal brain activation © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -24

+ Summary and Evaluation n Study of personality can be approached biologically n Two ways to think about how physiological variables are useful in personality theory and research… n Use physiological measures as variables that may be correlated with personality traits n View physiological events as providing causal substrate for personality trait © 2014 Mc. Graw-Hill Higher Education. All rights reserved. 7 -25