The Evolution of Disgust, Pathogens, and the Behavioural Immune System

Abstract

Throughout history, infectious diseases have been a constant threat to the survival and reproduction of humans and other animals. From an evolutionary perspective, infectious microorganisms (i.e., parasites, viruses, bacteria) are one of the most potent and ubiquitous selection pressures shaping the evolution of organisms susceptible to the diseases caused by these agents. As such, humans and other animals have developed a repertoire of emotional, cognitive, behavioural, and physiological mechanisms that function as protection against the persistent threat posed by infection. In the current chapter, we first provide an overview of past literature supporting the reasoning that key aspects of human psychology-disgust and the behavioural immune system-represent adaptations to the selection pressures posed by infectious microorganisms. We end by presenting innovative ideas bearing on disgust and the behavioural immune system, which incorporate perspectives from psychology, ecology, and psychoneuroimmunology.