Introversion-Extraversion

a) descriptive basis

(1) self reports

(a) sociable
(b) active
(c) spontaneous
(d) impulsive

(2) peer ratings

b) obvious behavioral correlates

(1) E's talk more

(a) but this interacts with group size
(b) more well known

(2) occupational differences

(a) extraversion and success in sales
(b) introversion and preference for isolation

(3) stimulation seeking

(a) higher risk of arrest
(b) interacts with social class

(4) greater sexual activity

(a) more partners
(b) earlier onset
(c) more positions

c) Theoretical-- causal bases --Biological Substrate of I/E

(1) differences in conditionability

(a) Eysenck's original hypothesis
- i) original hypothesis
  - (1) introverts are easily conditioned
  - (2) introverts become well socialized
- ii) later findings
  - (1) conditioning differences depend upon situation
  - (2) low arousal situations introverts condition more readily
    - Levy and Eysenck (1972)
  - (3) impulsivity more important than extraversion
(b) Alternative formulations of conditionability and extraversion
- i) Newman's work on psychopaths and extraversion
- ii) Gray's model of anxiety, impulsivity and conditioning
  - Zinbarg and Revelle (1989)
  - (1) sensitivity to cues of reward (impulsives)
  - (2) sensitivity to cues of punishment (anxiety)

(2) biological basis is difference in arousal

(a) what is arousal?
- i) arousal of the hand, the heart and the head
  - (1) Skin Conductance
  - (2) Heart Rate
  - (3) EEG
- ii) self report measures
  - (1) Energetic Arousal
  - (2) Tense Arousal
(b) basal arousal differences
- i) detected in psychophysiological experiments
  - (see Stelmack, 1990)
  - (1) Electro-encephalogram (EEG)
    - (a) Gale (1981)
    - (b) Gale & Coles
  - (2) Sedation Threshold
    - (a) Shagass
  - (3) Skin Conductance
    - (a) Revelle (1973)
    - (b) Wilson (1989)
  - (4) Spontaneous GSR
    - (a) Crider and Lunn (1971)
  - (5) Photic Driving
    - (a) Robinson (1982)
- ii) Threshold differences detected by psychophysical methods
  - (1) Light Sensitivity
    - (a) Siddle (1967)
  - (2) Sound Sensivity
    - (a) Smith (1968)
  - (3) Pain Sensitivity
    - (a) Haslam (1967)
    - (b) Petrie (1960)
  - (4) Bi-Modal sensitivity
    - (a) Shigehisa and Symons (1973)
  - (5) Reaction to lemon juice
    - (a) Eysenck, 1967
- iii) Body temperature and time of day
  - (1) Blake (1967)
  - (2) Folkard (1976)
  - (3) Eysenck and Folkard (1980)
(c) rates of change in arousal?
- i) stimuli tire (loose arousing properties) faster for extraverts
- ii) habituation of Orienting Response
- iii) Bowyer, Humphreys and Revelle, but see Anderson and Revelle

(3) behavioral consequences of arousal differences

(a) differences in arousal preference
- i) arousal level and hedonic tone
  - (1) Wundt's curvilinear hypothesis
    - (a) ³the Goldilocks hypothesis²
    - (b) moderate levels of arousal more pleasing than extreme levels
  - (2) Berlyne
    - (a) changes in arousal are more pleasing than a steady state
    - (b) increases or decreases
- ii) most preferred arousal level
  - (1) sound preference
    - (a) Elliott
    - (b) Hockey
  - (2) complexity preference
    - (a) Bartol
- iii) Extraversion and the 3 F syndrome
  - (1) Fags (cigarettes)
  - (2) Fornication
  - (3) Firewater
- iv) problems with arousal preference ideas
  - (1) what is arousing?
  - (2) what has subject been doing before coming to the lab?
    - (a) extraverts being sociabile
    - (b) introverts studying
(b) differences in performance under stress
- i) performance is a curvilinear function of arousal
  - (1) Yerkes and Dodson, 1908
    - (a) mice
    - (b) discrimination learning of 3 different levels of difficulty
    - (c) multiple levels of foot shock as a stressor
  - (2) Hebb, 1955
    - (a) level of "cue function" as function of arousal
    - (b) arousal as pleasing up to a point
- ii) performance as curvilinear function of arousal ==>
  - (1) introverts should do well under low stress situations
  - (2) extraverts should do well under high stress situations
- iii) evidence in support of this hypothesis
  - (1) no curvilinearity, but consistent
    - (a) Frith 1967
      - i) detection of flicker
      - ii) quiet versus noise
      - iii) extraverts versus introverts
    - (b) Corcoran 1972
      - i) tracking performance
      - ii) sleep deprivation (12, 36, 60 hours)
      - iii) extraversion-introversion
  - (2) curvilinearity and consistent
    - (a) Davies and Hockey 1966
      - i) detection task
      - ii) quiet versus noisey
      - iii) low versus high signal frequency
      - iv) extraverts versus introverts
    - (b) Gupta 1977
      - i) IQ tests
      - ii) 0,5,10, 15 mg ampetamine
      - iii) extraverts versus intraverts
    - (c) Revelle (1973)
      - i) performance on digit symbol, maze tracking and anagrams
      - ii) 1 person relaxed versus 2 person relaxed
      - iii) 2 relaxed versus 2 competitive versus 2 competive for money
      - iv) 2 competive for money versus 8 competitive for money
      - v) 8 competitive for money in quiet versus noise
      - vi) introversion versus extraversion
      - vii) mixed results
    - (d) Revelle Amaral and Turiff (1976)
      - i) Practice GRE's
      - ii) relaxed (take as long as you want)
      - iii) time pressure (10 minutes ) + placebo
      - iv) time pressure (10 minutes) + 200 mg caffeine
      - v) extraversion-introversion
- iv) complications
  - (1) Gilliland (1976) attempted to replicate Revelle et al. with a within subject design
    - (a) GRE's
    - (b) 0, 2, 4 mg of caffeine
    - (c) extraversion-introversion
      - i) old scale (Eysenck Personality Inventory)
      - ii) new (³improved²) scale (EPQ)
    - (d) EPQ did not support hypothesis
    - (e) EPI did
    - (f) what is the difference?
      - i) EPI measures sociability + impulsivity
      - ii) EPQ measures sociability
  - (2) Revelle, Humphreys, Simon and Gilliland (1980)
    - (a) complex ability tasks (mainly practice GRE's)
    - (b) 5 new + 2 old studies
      - i) results are stronger for imp than soc.
      - ii) interaction with time of day
      - iii) interaction with number of days in study
- v) implications of time of day results
  - (1) what is the stable trait?
    - (a) "why aren't introverts extraverts at night?"
  - (2) is it rate of change?
    - (a) yes
      - i) Bowyer, Humphreys, Revelle 1982
    - (b) no
      - i) Anderson and Revelle (1992)
      - ii) Revelle, Anderson & Rosenberg (1992)

(4) Psychological and applied significance of arousal findings

(a) as test of a theory of personality
- i) in general, the importance of interactions
- ii) time of day differences implies shortcoming in Eysenck's theory
- iii) experimental simple structure as a way of choosing alternative theory
(b) for individual differences work
- i) impulsivity as a normally distributed trait leading to differences in performance
- ii) impulsivity and attention deficit disorders
  - (1) sensitivity to stimulant drugs
  - (2) lack of impulse control
(c) for cognitive psychology
- i) for theory
  - (1) arousal affects three components of information processing differently
    - (a) arousal facilitates Sustained Information Transfer
    - (b) arousal hinders Working Memory
    - (c) arousal facilitates storage in Long Term Memory
  - (2) how is information organized
- ii) for applications
  - (1) task design for optimal performance
    - (a) vigilance tasks
      - i) radar operators
      - ii) truck drivers
      - iii) power plant monitoring
    - (b) STM tasks
      - i) short term memory as the span of consciousness
        (1) proof reading for contextual errors versus spelling errors
        (2) computer programming
        (3) writing
    - (c) LTM tasks
      - i) beneficial effects on educational learning
        (1) time of day effects on instruction
        (2) need to emphasize delayed recall to evaluate learning
  - (2) worker selection
    - (a) sustained tasks
    - (b) rapid responding tasks