Relationships between Introversion and Perceptual Accuracy

Abstract

In a recent article in this Journal Fine and Kobrick (1976) reported a significant relationship between introversion and the accuracy of target detection: the introverts being more accurate than the extraverts. The finding was interpreted as being central-nervoussystem-based differences in human perception. To test if that relationship was due to general perceptual processes or an effect of the specific perceptual test used by the authors 48 male human subjects (psychology undergraduates) practiced on a track-tracing device as described by Fleishman (1958). This test resulted in two individual scores for motor speed (MS) and motor accuracy (MA). Thereafter, 120 slides taken from the same device with a randomly scattered point as a target were projected by a tachistoscope while the subject had to decide if the target was in the track or out of it. The sum of reaction times yielded a score of perceptual speed (PS), the number of accurate decisions was taken as a score of perceptual accuracy (PA). These four scores were intercorrelated: significant (p < .01) convergent relationships were calculated for PS, MS (r = .34) and for PA, MA (r = .40), whereas the discriminant relationships (PA:MS; MA:PS) were low and statistically not different from zero. A score of introversion had been measured by means of a German standardized version of the Maudsley Personality Inventory (Brengelmann & Brengelmann, 1960). None of the relationships between introversion and the four performance scores exceeded .14, and so were not significant. According to our results no relationships were obtained for introversion and perceptual accuracy by means of a valid test of target detection. This finding is supported by the results of Keister and McLaughlin (1972) who did not find a perceptual difference between introverts and extraverts either. However, Keister and McLaughlin report a performance decrement for the extraverts due to a long exposure to a vigilance task. Consequently, the relationship between introversion and perceptual accuracy found by Fine and Kobrick might be associated with fatigue and not a result of perceptual processes. This interpretation fits neatly into the satiation concept proposed by Eysenck (1967) for the explanation of behavioral differences between introverts and extraverts, because our perceptual task lasted only for 3 min., that of Fine and Kobrick for 42 min.