REGRESSION AND CRITERION MEASURES OF HABITUATION - A COMPARATIVE-ANALYSIS IN EXTROVERTS AND INTROVERTS

The Eysenck theory of extraversion leads to the hypothesis that extraverts show more rapid psychophysiological habituation than introverts. Previous tests of this hypothesis have yielded mixed results, possibly due to various methodological variations and limitations. Prior studies have typically recorded from only one side of the body, have often used relatively small sample sizes, have frequently employed median split designs, and have almost exclusively used a criterion habituation procedure. The present study recorded electrodermal activity bilaterally and intercompared regression and criterion measures of habituation, using a large sample representing the extremes of the extraversion dimension. Initial response amplitude data showed a pattern of differential lateral asymmetry that was an interactive function of sex and extraversion (p < .05). The regression measure of habituation rate, involving a regression coefficient corrected for the influence of the intercept, showed more rapid habituation in extraverts than in introverts (p < .05) and more rapid habituation in males than in females (p < .05). The criterion measure yielded no differences. Since results that were significant reached only the .05 level of reliability, replication is needed. In addition, present results suggest the need for studies that would examine the differential effects in introverts and extraverts of arousal induced by systematically varied intensities of stimulation. © 1990.