1. PERSONALITY PSY234 Lecture 5: Trait & Type approaches Dr Simon Boag Email: simon.boag@psy.mq.edu.au

2. Readings Carver, C. S. & Scheier, M. F. (2004). Perspectives on Personality. (pp. 156-160) Carver, C. S. & Scheier, M. F. (2004). Perspectives on Personality. (pp. 156-160) Monte, C. F. & Sollod, R. N. (2003). Beneath the mask. (pp. 597-614) Monte, C. F. & Sollod, R. N. (2003). Beneath the mask. (pp. 597-614) Additional (non-assessable) Eysenck, H. J. (1967). The Biological Basis of Personality. Springfield: Thomas. Eysenck, H. J. (1967). The Biological Basis of Personality. Springfield: Thomas. McCrae, R. R. & Costa, P. T. (1997). Personality trait structure as a human universal. American Psychologist, 52, 509-516 McCrae, R. R. & Costa, P. T. (1997). Personality trait structure as a human universal. American Psychologist, 52, 509-516

3. Lecture Outline I. Eysenck’s dimensional approach Extroversion vs introversion Extroversion vs introversion Neuroticism vs normality Neuroticism vs normality Personality temperaments Personality temperaments II. Biological basis of personality ARAS & visceral brain ARAS & visceral brain III. Summary & evaluation

4. Learning Outcomes After this lecture you should be able to: Understand & explain the meaning of personality ‘type’, ‘trait’ & ‘dimension’ Understand & explain the meaning of personality ‘type’, ‘trait’ & ‘dimension’ Describe & explain ‘extroversion’, ‘introversion’, ‘neuroticism’ & ‘normality’ Describe & explain ‘extroversion’, ‘introversion’, ‘neuroticism’ & ‘normality’ Understand the relation of dimensions to personality temperaments Understand the relation of dimensions to personality temperaments Describe & explain Eysenck’s biological explanation for personality differences Describe & explain Eysenck’s biological explanation for personality differences

5. Types & Traits Traits: An enduring characteristic of a person’s behaviour eg. sociable/unsociable Types: A class of individuals with common characteristic or pattern of characteristics (physical/psychological) eg. Sheldon (1942) Varieties of Temperament

7. Personality Types Hippocrates (460?-377?BC) & Galen (130- 200? AD): personality based on humors Hippocrates (460?-377?BC) & Galen (130- 200? AD): personality based on humors Sanguine (blood) Warm-hearted, optimistic Warm-hearted, optimistic Melancholic (black bile) Sad, depressed, anxious Sad, depressed, anxious Choleric (yellow bile) Quick tempered, angry, assertive Quick tempered, angry, assertive Phlegmatic (phlegm) Slow, lethargic, calm Slow, lethargic, calm

9. Eysenck’s Theory of Personality Hans Eysenck (1916-1997)

10. Eysenck’s Approach Identifying universal, measurable dimensions of personality Identifying universal, measurable dimensions of personality Rejects unique individual: “… the unique individual is simply the point of intersection of a number of quantitative variables” (Eysenck, 1952, p.18). Rejects unique individual: “… the unique individual is simply the point of intersection of a number of quantitative variables” (Eysenck, 1952, p.18). Identified through large scale assessment Identified through large scale assessment eg. US Airforce personnel eg. US Airforce personnel Statistical approach: Factor analysis Statistical approach: Factor analysis

11. Personality Dimensions (1): Introversion/Extroversion Adapted from Jung’s types Extrovert: Outgoing, embraces the world, responsive to social & physical stimulation Outgoing, embraces the world, responsive to social & physical stimulation Insensitive to stimulation (‘stimulus hungry’) Insensitive to stimulation (‘stimulus hungry’) Introvert: Hesitant, reflective, withdraws from social & physical stimulation Hesitant, reflective, withdraws from social & physical stimulation Sensitive to stimulation (‘stimulus shy’) Sensitive to stimulation (‘stimulus shy’)

12. Extroversion/Introversion Dimension : relative degree (more or less) Dimension : relative degree (more or less) Introvert X Y Z Extrovert Extrovert: sociable, outgoing, interactive, expressive, sensation seeking, acts first, think later, dislikes being alone Extrovert: sociable, outgoing, interactive, expressive, sensation seeking, acts first, think later, dislikes being alone Introvert: private, reclusive, reserved, quiet, inward, sensitive, thinks before acting, exhausted by groups Introvert: private, reclusive, reserved, quiet, inward, sensitive, thinks before acting, exhausted by groups

13. Personality Dimension (2): Neuroticism/Normality Emotional vs non-emotional (Wundt) Emotional vs non-emotional (Wundt) Refers to strength of emotional reaction not psychopathology Refers to strength of emotional reaction not psychopathology High degree of neuroticism: More emotionally reactive More emotionally reactive eg. moody, tense, anxious, irritable eg. moody, tense, anxious, irritable High degree of normality: Less emotionally reactive (but still have emotions) Less emotionally reactive (but still have emotions)

14. Dimensions: Persons X & Y Introversion/Extroversion: Intr. X Y Extr. Neuroticism/Normality: Neur. Y X Norm. These dimensions are orthogonal These dimensions are orthogonal

15. Test Items (EPQ) Introversion/Extroversion eg. ‘Do you prefer reading to meeting people?’ Neuroticism/Normality eg. ‘Are your feelings easily hurt?’ Later added another dimension: Psychoticism (anti-social trait) eg. ‘Would you like other people to be afraid of you?’

16. Some empirical findings ‘Criminals’ score high in E, N & P (Eysenck & Eysenck, 1985) ‘Criminals’ score high in E, N & P (Eysenck & Eysenck, 1985) Creative people score high on psychoticism (Eysenck, 1993, 1994) Creative people score high on psychoticism (Eysenck, 1993, 1994) Extroverts more willing to have sexual contact without commitment & report more sexual experience (Wright & Reise, 1997) Extroverts more willing to have sexual contact without commitment & report more sexual experience (Wright & Reise, 1997)

17. Eysenck’s Personality Types Dimensional interaction produces ‘types’: Dimensional interaction produces ‘types’: (1) Extrovert (neurotic): Choleric: bad tempered (2) Extrovert (normal): Sanguine: cheerful (3) Introvert (neurotic): Melancholic: gloomy (4) Introvert (normal): Phlegmatic: unemotional, indifferent

19. II. The Biological Basis of Personality Personality types result from differences in central nervous system (CNS) functioning Personality types result from differences in central nervous system (CNS) functioning Implications: Genetic basis of personality Genetic basis of personality Relatively stable & unchanging Relatively stable & unchanging However: environment interacts with biological predispositions However: environment interacts with biological predispositions

20. Biological Basis of Extroversion/Introversion ARAS system: Ascending Reticular Activation System Ascending Reticular Activation System Cortical excitation & inhibition Cortical excitation & inhibition High ARAS arousal: Predisposes to introversion Predisposes to introversion Low ARAS arousal: Predisposes to extroversion Predisposes to extroversion Evidence: Introverts have higher sedation threshold than extroverts (cf. ADHD)

21. Some empirical findings Introverts less tolerant of painful electric shocks (Bartol & Costello, 1976) Introverts less tolerant of painful electric shocks (Bartol & Costello, 1976) Corr et al (1995): After high dose of caffeine: Introverts poorer performance (over-stimulated?); Extroverts better performance (stimulated?) Corr et al (1995): After high dose of caffeine: Introverts poorer performance (over-stimulated?); Extroverts better performance (stimulated?) Frontal lobes of introverts more active than extroverts (PET scan) (Johnson et al, 1999) Frontal lobes of introverts more active than extroverts (PET scan) (Johnson et al, 1999)

22. Biological Basis of Neuroticism/Normality Visceral Brain (VB) system Hypothalamus & limbic system Hypothalamus & limbic system Mediates emotional activation Mediates emotional activation High VB activation: Predisposed to neuroticism (emotionally reactive) Predisposed to neuroticism (emotionally reactive) Low VB activation: Predisposed to normality (non- emotionally reactive) Predisposed to normality (non- emotionally reactive)

24. Extroverts: Normal & Neurotic Sanguine Normal Extrovert Low ARAS arousal Low ARAS arousal Low visceral brain activity Low visceral brain activityCholeric Neurotic Extrovert Low ARAS arousal Low ARAS arousal High visceral brain activity High visceral brain activity

25. Introverts: Normal & Neurotic Phlegmatic Normal Introvert High ARAS arousal High ARAS arousal Low visceral brain activity Low visceral brain activityMelancholic Neurotic Introvert High ARAS arousal High ARAS arousal High visceral brain activity High visceral brain activity

26. Biological & Environmental Interaction “Biological causes act in such a way as to predispose an individual in certain ways to stimulation; this stimulation may or may not occur, depending on circumstances which are entirely under environmental control” (Eysenck, 1967, pp. 221-222) Effect of different teaching environments Effect of different teaching environments

27. III. Evaluation Twin studies: E & N: 50% genetic Twin studies: E & N: 50% genetic Adoption studies: Correlations b/w adoptive parents & adopted children for E & N are around 0% Adoption studies: Correlations b/w adoptive parents & adopted children for E & N are around 0% E, N & P: highest validity of all traits (Kline, 1993) E, N & P: highest validity of all traits (Kline, 1993) Contradictory findings (eg. sedation findings) Contradictory findings (eg. sedation findings) Hypothesised brain areas are not independent of one another Hypothesised brain areas are not independent of one another

28. Evaluation Forms basis of subsequent trait theories Forms basis of subsequent trait theories eg. ‘Big Five Factor model’ (McCrae & Costa, 1997) Neuroticism, extroversion, openness, conscientiousness, agreeableness Neuroticism, extroversion, openness, conscientiousness, agreeableness Is personality really stable? Is personality really stable? Situationism (Mischel, 1990): situations are strongest determinants of behaviour Situationism (Mischel, 1990): situations are strongest determinants of behaviour eg. child shy with strangers, friendly with parents eg. child shy with strangers, friendly with parents

29. Summary Eysenck’s approach identifies personality dimensions (ext/int; neu/nor) Eysenck’s approach identifies personality dimensions (ext/int; neu/nor) A person’s placing on these dimensions determines their personality temperament A person’s placing on these dimensions determines their personality temperament Eysenck proposes a biological basis for personality Eysenck proposes a biological basis for personality Extroversion & introversion are said to be related to ARAS functioning Extroversion & introversion are said to be related to ARAS functioning Neuroticism & normality are said to be related to visceral brain activity Neuroticism & normality are said to be related to visceral brain activity