Health Is Associated With Antiparasite Behavior and Fear of Disease-Relevant Animals in Humans

Evolutionary arms races between humans and parasites resulted in a set of behavioral adaptations that serve as parasite-avoidance mechanisms. We investigated associations among reported health of the respondent, antiparasite behavior, and sensitivity to disgust and fear of disease-relevant and irrelevant animals. Ninety-seven participants (15-19 years old) rated their fear and disgust at 25 colorful pictures of disease-relevant and disease-irrelevant invertebrates. Consistent with previous work, we found that participants reported greater fear and disgust of disease-relevant invertebrates relative to disease-irrelevant invertebrates. Better perceived health correlated with lower fear of disease-relevant invertebrates. Sensitivity to disgust correlated with reported antiparasite behaviors. Contrary to expectations, we found a positive correlation between antiparasite behavior and reported health, which suggests that antiparasite behavior influences perceived health (but not vice versa), and we found that males perform more antiparasite behaviors than females. These results support the idea that disgust and fear of disease-relevant objects are adaptive emotions that prevent contact with contagious objects, especially in individuals with low perceived health.