Individual differences in mismatch negativity measures of involuntary attention shift.
OBJECTIVE
The purpose of this study was to compare the automatic detection of deviance in introverts and extraverts. Event-related potentials were recorded to standard and deviant stimuli. These were presented either rapidly or slowly. Stimuli that are presented slowly may intrude into consciousness.


METHODS
Twenty subjects were tested and divided into introverted and extraverted groups. A 500 Hz standard stimulus was presented on 85% of trials. On the remaining 15% of trials, a 750 Hz deviant was presented. In separate conditions, stimuli were presented rapidly (every 500 ms) or slowly (every 1500 ms). Subjects ignored the stimuli while reading.


RESULTS
The deviant stimulus elicited a mismatch negativity (MMN) in both conditions. No inter-group differences in the MMN emerged when a rapid rate of presentation was employed. When a slower rate was employed, a late negativity was significantly larger for the extraverted than the introverted group. This was followed by a late positive wave.


CONCLUSIONS
The late negative-positive complex is thought to reflect intrusiveness. It would therefore appear that extraverts are more distractible than introverts when stimuli are presented slowly.
Sasaki
T
T
School of Psychology, University of Ottawa, K1N 6N5, Ottawa, Canada. tosasaki@infoaomori.ne.jp
Campbell
K B
KB
Gordon Bazana
P
P
Stelmack
R M
RM
D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D011930:Reaction Time / Q000502:physiology; D013647:Task Performance and Analysis