Reasoning Improves in Response to Threats of Contagion and Food Contamination

Abstract

A large body of evidence demonstrating the shifts in attitudes and behavior towards threats of illness suggests that humans have evolved to detect and avoid sources of contagion, which Schaller (Psychological Inquiry, 17(2), 96–137, 2006) labeled the behavioral immune system. In the present study, subjects engaged in a reasoning task (the Wason selection task) in order to uncover possible sources of contagion or contaminated food. I predicted that the behavioral immune system would direct subjects to correct responses more often when reasoning about possible threats than when threats were absent in the scenarios. The results revealed a systematic increase in likelihood to reason correctly when threats of illness were present. This was true for both the threat of contagion and the threat of contaminated food. These findings suggest the behavioral immune system influences reasoning, possibly by directing attention to key elements in the reasoning scenario.