Using the Eysenck Personality Questionnaire-Revised, 67 female subjects were classified into three extraversion groups, introverts, ambiverts, and extraverts. Event-related brain potentials were recorded concurrently with response time measures as participants performed simple reaction time and stimulus-response compatibility tasks. Response time was differentiated into reaction time and movement time. The auditory simple reaction time task varied motor task requirements by varying the distance of the response button from the home button, and also varied stimulus intensity. The stimulus-response compatibility task varied stimulus evaluation demands by using arrays comprised of a middle arrow with flankers either congruent or incongruent with its direction, and varied response requirements by using instructions indicating whether the response was compatible or incompatible with the direction of the middle arrow. There was no overall effect of extraversion group on P3 latency or RT. Group differences were apparent, however, on measures of N1 amplitude, with introverts displaying larger amplitudes than extraverts. This result is consistent with introverts' greater reactivity to stimulation than extraverts. Behaviourally, on both tasks, extraverts tended to have faster movement times than introverts. Further, on the simple reaction time task, the magnitude of the difference in movement time between introverts and extraverts remained constant across the response button distances, indicating that the differences are occurring in the initial phase of the movement, rather than in the ballistic phase. These results are in accordance with a sensory-motor theory of extraversion that underscores the importance of reactivity to sensory stimuli, and speed of motor responding.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/8469 |
| Date | January 1999 |
| Creators | Doucet, Cynthia. |
| Contributors | Stelmack, R., |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 113 p. |
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