Extraversion and vigilance performance: 30 years of inconsistencies.

Deteriorating efficiency in detecting critical events is a pervasive phenomenon. It has been asserted that the personality dimension of extraversion-introversion (E-I) could serve as a selection device: Introverts would be superior in sustained attention. A meta-analysis revealed better performance of introverts, but the effect size was small because of a high incidence of inconsistencies. In a subset of the studies, the effect size was much larger: Introverts were superior in overall level of correct detections but not in maintaining efficiency over time. Inconsistent findings may partly have been caused by inappropriate use of univariate analysis of variance in repeated measures designs. The validity of some "classic" findings in the vigilance literature was questioned. The relationship of E-I to electrodermal speed of habituation was discussed. Finally, here also a trend was noted to move to new problems before solving old ones.