Abstract
It has long been recognized in the nonverbal communication literature that individual differences in extraversion are expected to be most clearly evident in expressive forms of nonverbal behavior. Although several studies designed to examine the correlation between extraversion and nonverbal behavior have been conducted, most attempts to summarize these studies reflect the inconsistent nature of the research findings. Indeed, correlations range from −.36 to .73. The extant literature summaries are limited to narrative reviews, however, which tend to be highly selective. The purpose of this study was to meta-analyze the relevant studies. Results indicated that the mean correlation coefficient weighted for sample size was .13 for the entire sample of studies. Although 63% of the variance was attributable to sampling error, the distribution of correlations was heterogeneous. The remaining variance was due to two methodological artifacts: sample size and the number of nonverbal behaviors coded. For example, hierarchical breakdowns by moderator indicated that the mean correlation was .50 for highly focused studies-those in which researchers concentrated on a few behaviors and limited coding to 40 or fewer subjects. A cognitive-overload model for these findings is offered and corroborated by findings from other research domains. Implications for communication research and theory are discussed. In addition to clarifying the empirical relationship between extraversion and nonverbal behavior, the contributions of this study reside, in part, in its implications for large samples and large numbers of nonverbal behaviors coded in research and for meta-analyses of such research literatures.
