Physiological Approaches to Personality Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Sheldon’s Physiological Approach to Personality Argued that body type determines personality Argued that body type determines personality Ectomorph (skinny): Thoughtful, introverted Ectomorph (skinny): Thoughtful, introverted Mesomorph (muscular): Assertive, bold Mesomorph (muscular): Assertive, bold Endomorph (fat): Sociable, fun-loving Endomorph (fat): Sociable, fun-loving

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sheldon’s Physiological Approach to Personality Did not use blind ratings, most later research failed to replicate Did not use blind ratings, most later research failed to replicate Some work suggesting relationship between body type and job choice Some work suggesting relationship between body type and job choice Physiological personality psychologists today do not focus on global variables such as body type Physiological personality psychologists today do not focus on global variables such as body type

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Physiological Measures Commonly Used in Personality Research Electrodermal Activity (Skin Conductance) Electrodermal Activity (Skin Conductance) Cardiovascular activity Cardiovascular activity Brain Activity Brain Activity Other measures: Biochemical analyses of blood and saliva Other measures: Biochemical analyses of blood and saliva

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Electrodermal Activity (EDA): Skin Conductance Most obtained by electrodes or sensors placed on the skin surface Most obtained by electrodes or sensors placed on the skin surface Advantage: Noninvasive, no discomfort Advantage: Noninvasive, no discomfort Disadvantage: Movement constrained Disadvantage: Movement constrained

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Electrodermal Activity (EDA): Skin Conductance Electrodermal activity—due to increased sweat with arousal, skin conductance of electricity increases Electrodermal activity—due to increased sweat with arousal, skin conductance of electricity increases Can measure responses to various stimuli, including sudden noises, emotionally charged pictures, pain, anxiety, fear, guilt Can measure responses to various stimuli, including sudden noises, emotionally charged pictures, pain, anxiety, fear, guilt Some people show EDA in the absence of external stimuli—associated with anxiety and neuroticism Some people show EDA in the absence of external stimuli—associated with anxiety and neuroticism

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cardiovascular activity Blood pressure—measure of, e.g., stress reactivity Blood pressure—measure of, e.g., stress reactivity Heart rate—increases with anxiety, fear, arousal, cognitive effort Heart rate—increases with anxiety, fear, arousal, cognitive effort

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cardiovascular activity Cardiac reactivity—greater than normal increase in blood pressure and heart rate when performing task such as backward serial subtraction Cardiac reactivity—greater than normal increase in blood pressure and heart rate when performing task such as backward serial subtraction Associated with Type A personality—impatience, competitiveness, hostility Associated with Type A personality—impatience, competitiveness, hostility Cardiac reactivity (and Type A) associated with coronary heart disease Cardiac reactivity (and Type A) associated with coronary heart disease

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brain Activity Brain spontaneously produces small amounts of electrical activity; can be Brain spontaneously produces small amounts of electrical activity; can be measured by electrodes on scalp— electroencephalograph (EEG) measured by electrodes on scalp— electroencephalograph (EEG) Evoked potential technique—uses EEG, but the participant is given a stimulus and the researcher assess specific brain response to stimulus Evoked potential technique—uses EEG, but the participant is given a stimulus and the researcher assess specific brain response to stimulus

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brain Activity Brain imaging techniques—map structure and function of brain Brain imaging techniques—map structure and function of brain Positron emission tomography (PET) Positron emission tomography (PET) Functional magnetic resonance imaging (fMRI) Functional magnetic resonance imaging (fMRI)

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. EEG (Electroencephelagram) How it works: Electrodes placed on the scalp record voltage differences between different parts of the brain How it works: Electrodes placed on the scalp record voltage differences between different parts of the brain Pros: Pros: High temporal resolution, High temporal resolution, Measures neuronal activity directly (via electrical output), Measures neuronal activity directly (via electrical output), Relatively easy to use. Relatively easy to use. Cons: Cons: Limited to surface (cortical) activity Limited to surface (cortical) activity Limited spatial resolution/anatomical specificity Limited spatial resolution/anatomical specificity

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pet (Positron emission tomography) How it works: A scanning device reads the positron emissions that are released as a previously injected sugar decays. Thus, it can assess the blood flow, oxygen and glucose consumption in different parts of the brain. How it works: A scanning device reads the positron emissions that are released as a previously injected sugar decays. Thus, it can assess the blood flow, oxygen and glucose consumption in different parts of the brain. Pros: Pros: Unlike EEG, offers 3D resolution Unlike EEG, offers 3D resolution Can measure several metabolic indicators Can measure several metabolic indicators Tracers can reveal neurotransmitter receptors/transporters Tracers can reveal neurotransmitter receptors/transporters Cons: Cons: Requires radioactive injections Requires radioactive injections Radioactive half life means only short tasks can be measured Radioactive half life means only short tasks can be measured Blood flow, oxygen and glucose consumption are all indirect correlates of brain activity Blood flow, oxygen and glucose consumption are all indirect correlates of brain activity

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. MRI (magnetic resonance imaging) How it works: Uses magnetic fields and radio waves to produce high quality images by manipulating the spin of hydrogen protons How it works: Uses magnetic fields and radio waves to produce high quality images by manipulating the spin of hydrogen protons Pros: Pros: No radioactive tracers needed No radioactive tracers needed High resolution imaging High resolution imaging Can register water content, inflammation and bleeding Can register water content, inflammation and bleeding Cons: Cons: Can only register structure, and not function Can only register structure, and not function

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. fMRI (functional magnetic resonance imaging) How it works: Adapts MRI to register the magnetic properties of oxygenated and deoxygenated hemoglobin, allowing real-time blood flow to be imaged How it works: Adapts MRI to register the magnetic properties of oxygenated and deoxygenated hemoglobin, allowing real-time blood flow to be imaged Pros: Pros: Can see activation in addition to high res brain structures Can see activation in addition to high res brain structures Scanners can be fitted to present stimuli Scanners can be fitted to present stimuli Higher spatial and temporal resolution than PET Higher spatial and temporal resolution than PET Cons: Cons: Cannot trace neurotransmission like PET Cannot trace neurotransmission like PET Blood flow is, again, only an indirect correlate of brain activity Blood flow is, again, only an indirect correlate of brain activity

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TMs (transcranial magnetic stimulation) How it works: Targeted magnetic pulses temporarily excite sugar-cube sized groups of neurons, allowing increases or decreases in neuronal excitability How it works: Targeted magnetic pulses temporarily excite sugar-cube sized groups of neurons, allowing increases or decreases in neuronal excitability Pros: Pros: Can manipulate activation rather than just image it, allowing causality to be inferred Can manipulate activation rather than just image it, allowing causality to be inferred Temporary with no lasting damage Temporary with no lasting damage Cons: Cons: Researchers still unclear on how it works, exactly Researchers still unclear on how it works, exactly 1cm 3

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Physiologically Based Dimensions of Personality Extraversion-Introversion Extraversion-Introversion Sensitivity to Reward and Punishment Sensitivity to Reward and Punishment Sensation Seeking Sensation Seeking Neurotransmitters and Personality Neurotransmitters and Personality Morningness-Eveningness Morningness-Eveningness Brain Asymmetry and Affective Style Brain Asymmetry and Affective Style

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Extraversion-Introversion Measured by Eysenck Personality Questionnaire (EPQ) Measured by Eysenck Personality Questionnaire (EPQ) High extraversion: Talkative, outgoing, likes meeting new people and going to new places, active, bored easily, hates routine High extraversion: Talkative, outgoing, likes meeting new people and going to new places, active, bored easily, hates routine Low extraversion: Quiet, withdrawn, prefers being alone or with a few friends to large crowds, prefers routines, prefers familiar to unexpected Low extraversion: Quiet, withdrawn, prefers being alone or with a few friends to large crowds, prefers routines, prefers familiar to unexpected

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Extraversion-Introversion Eysenck’s theory Introverts have a higher level than extraverts of activity in the brain’s ascending reticular activating system (ARAS) Introverts have a higher level than extraverts of activity in the brain’s ascending reticular activating system (ARAS) People strive to keep ARAS activity at optimal level—introverts work to decrease and avoid stimulation; extraverts work to increase and seek out stimulation People strive to keep ARAS activity at optimal level—introverts work to decrease and avoid stimulation; extraverts work to increase and seek out stimulation

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Extraversion-Introversion Eysenck’s theory Research indicates that introverts and extraverts are NOT at different resting levels, but introverts ARE more reactive to moderate levels of stimulation than extraverts Research indicates that introverts and extraverts are NOT at different resting levels, but introverts ARE more reactive to moderate levels of stimulation than extraverts This work led Eysenck to revise his theory—the difference between introverts and extraverts lies in arousability, not in baseline arousal This work led Eysenck to revise his theory—the difference between introverts and extraverts lies in arousability, not in baseline arousal

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Extraversion-Introversion Eysenck’s theory When given a choice, extraverts prefer higher levels of stimulation than introverts When given a choice, extraverts prefer higher levels of stimulation than introverts Geen (1984): Introverts and extraverts choose different levels of stimulation, but equivalent in arousal under chosen stimulation Geen (1984): Introverts and extraverts choose different levels of stimulation, but equivalent in arousal under chosen stimulation

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Extraversion-Introversion Eysenck’s theory Introverts and extraverts perform task best under their chosen stimulation level, poor when performing under a stimulation level chosen by other group Introverts and extraverts perform task best under their chosen stimulation level, poor when performing under a stimulation level chosen by other group

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sensitivity to Reward and Punishment Personality based on two hypothesized brain systems Personality based on two hypothesized brain systems Behavioral Activation System (BAS): Responsive to incentives (cues to reward) and regulates approach behavior Behavioral Activation System (BAS): Responsive to incentives (cues to reward) and regulates approach behavior

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sensitivity to Reward and Punishment Behavioral Inhibition System (BIS): Responsive to cues to punishment, frustration, uncertainty, and motivates ceasing, inhibiting, or avoidance behavior Behavioral Inhibition System (BIS): Responsive to cues to punishment, frustration, uncertainty, and motivates ceasing, inhibiting, or avoidance behavior Active BIS produces anxiety, active BAS produces impulsivity Active BIS produces anxiety, active BAS produces impulsivity

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sensitivity to Reward and Punishment Integration with Eysenck’s model: Impulsive = high extraversion, moderate neuroticism; Anxious = moderate introversion, high neuroticism Integration with Eysenck’s model: Impulsive = high extraversion, moderate neuroticism; Anxious = moderate introversion, high neuroticism According to Gray, impulsive people do not learn well from punishment because of weak BIS; learn better from reward—supported by research According to Gray, impulsive people do not learn well from punishment because of weak BIS; learn better from reward—supported by research

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sensation Seeking Tendency to seek out thrilling, exciting activities, take risks, avoid boredom Tendency to seek out thrilling, exciting activities, take risks, avoid boredom Early sensory deprivation research Early sensory deprivation research Hebb’s theory of optimal level of arousal Hebb’s theory of optimal level of arousal

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sensation Seeking Zuckerman: High sensation seekers are less tolerant of sensory deprivation; require much stimulation to get to optimal level of arousal Zuckerman: High sensation seekers are less tolerant of sensory deprivation; require much stimulation to get to optimal level of arousal Zuckerman’s Sensation Seeking Scale Zuckerman’s Sensation Seeking Scale Moderate positive correlation between extraversion and sensation seeking Moderate positive correlation between extraversion and sensation seeking

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sensation Seeking Physiological basis for sensation seeking Physiological basis for sensation seeking Neurotransmitters—chemicals in nerve cells are responsible for the transmission of nerve impulse from one cell to another Neurotransmitters—chemicals in nerve cells are responsible for the transmission of nerve impulse from one cell to another Monoamine Oxidase (MAO)—enzyme that maintains a proper level of neurotransmitters Monoamine Oxidase (MAO)—enzyme that maintains a proper level of neurotransmitters

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sensation Seeking Physiological basis for sensation seeking Physiological basis for sensation seeking Too little MAO = too much neurotransmitter; too much MAO = too little neurotransmitter Too little MAO = too much neurotransmitter; too much MAO = too little neurotransmitter High sensation seekers have low levels of MAO, producing a need for stimulation to reach the optimal level of arousal High sensation seekers have low levels of MAO, producing a need for stimulation to reach the optimal level of arousal

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Neurotransmitters and Personality Dopamine—associated with pleasure Dopamine—associated with pleasure Serotonin—associated with depression and other mood disorders Serotonin—associated with depression and other mood disorders Norepinepherine—associated with fight or flight response Norepinepherine—associated with fight or flight response

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Neurotransmitters and Personality Cloninger’s Tridimensional Personality Model Novelty seeking—low levels of dopamine Novelty seeking—low levels of dopamine Harm avoidance—low levels of serotonin Harm avoidance—low levels of serotonin Reward dependence—low levels of norephinepherine Reward dependence—low levels of norephinepherine

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Morningness-Eveningness Being a “morning-type” or “evening-type” of person is a stable characteristic Being a “morning-type” or “evening-type” of person is a stable characteristic Due to differences in underlying biological rhythms Due to differences in underlying biological rhythms

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Morningness-Eveningness Many biological processes fluctuate around a hour cycle—circadian rhythm; e.g., body temperature, endocrine secretion rates Many biological processes fluctuate around a hour cycle—circadian rhythm; e.g., body temperature, endocrine secretion rates But wide individual differences are in the circadian rhythm, identified through temporal isolation studies But wide individual differences are in the circadian rhythm, identified through temporal isolation studies

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Morningness-Eveningness Individuals with shorter circadian rhythms hit peak body temperature and alertness earlier in day, get sleepy earlier, than individuals with longer rhythm Individuals with shorter circadian rhythms hit peak body temperature and alertness earlier in day, get sleepy earlier, than individuals with longer rhythm Individuals with shorter rhythm tend to be morning persons; individuals with longer rhythms tend to be evening persons Individuals with shorter rhythm tend to be morning persons; individuals with longer rhythms tend to be evening persons

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Morningness-Eveningness Morningness-Eveningness Questionnaire Morningness-Eveningness Questionnaire Cross-cultural replication and documentation of stability of characteristic Cross-cultural replication and documentation of stability of characteristic

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Experiment: Lateralization and Mood Instructions On each of the following 10 screens you will see a line that is bisected near the middle. For each line, please indicate with an R (Right side) or an L (Left side) which half of the line appears larger to you. On each of the following 10 screens you will see a line that is bisected near the middle. For each line, please indicate with an R (Right side) or an L (Left side) which half of the line appears larger to you.

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Line 1

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Line 2

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Line 3

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Line 4

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Line 5

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Line 6

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Line 7

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Line 8

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Line 9

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Line 10

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brain Asymmetry and Affective Style Left and right sides of the brain are specialized, with asymmetry in control of psychological functions Left and right sides of the brain are specialized, with asymmetry in control of psychological functions Using EEG, can measure brain waves, such as alpha wave—an inverse indicator of brain activity Using EEG, can measure brain waves, such as alpha wave—an inverse indicator of brain activity

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brain Asymmetry and Affective Style 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 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 Patterns replicated in adults, children, and infants Patterns replicated in adults, children, and infants

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brain Asymmetry and Affective Style Research indicates that the tendency to exhibit asymmetry (favoring left over right, or right over left activation) is a stable individual characteristic Research indicates that the tendency to exhibit asymmetry (favoring left over right, or right over left activation) is a stable individual characteristic Dispositionally positive persons show greater left frontal EEG activity; dispositionally negative persons show greater right frontal EEG activity Dispositionally positive persons show greater left frontal EEG activity; dispositionally negative persons show greater right frontal EEG activity

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brain Asymmetry and Affective Style Conclusion: Person’s affective lifestyle may have origins in, or be predicted by a pattern of asymmetry in frontal brain activation Conclusion: Person’s affective lifestyle may have origins in, or be predicted by a pattern of asymmetry in frontal brain activation

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Summary and Evaluation Study of personality can be approached biologically Study of personality can be approached biologically Two ways to think about how physiological variables are useful in personality theory and research… Two ways to think about how physiological variables are useful in personality theory and research…

Copyright © 2005 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Summary and Evaluation (continued) Use physiological measures as variables that may be correlated with personality traits Use physiological measures as variables that may be correlated with personality traits View physiological events as providing causal substrate for personality trait View physiological events as providing causal substrate for personality trait