A meta-analysis of perceived infectability, germ aversion, disgust and outgroup perceptions: Evaluating research on the behavioural immune system.

Scholarship on the behavioural immune system suggests that people who perceive themselves as more susceptible to illnesses are more sensitive to disgust, providing an evolutionary advantage to avoid pathogenic stimuli. This sensitivity causes those with greater perceived susceptibility to be biased against outgroup members and avoid those with dissimilar immunological histories. However, the lack of a quantitative review forces researchers to derive arguments from specific empirical observations, rather than holistically drawing from averaged effects across studies. Researchers may over-rely on studies that produced atypical results, causing biases in research on perceived infectability, germ aversion, disgust and outgroup perceptions. To resolve this tension in the literature, we perform a meta-analysis of 74 sources. Our meta-analytic results demonstrate that perceived infectability produces small relations with disgust and non-significant relations with outgroup perceptions, whereas a construct commonly conflated with perceived infectability, germ aversion, produces larger relations with these two outcomes. A meta-analytic structural equation model demonstrates that the indirect effect of perceived infectability on outgroup perceptions via the mediator of disgust is not statistically significant. These findings indicate that, while perceived infectability relates to disgust, the construct does not relate to perceptions of outgroup members, counter to scholarship on the behavioural immune system.