Reciprocal relationship between the emotion of disgust, its neural substrates, and its linkages into the immune system

In response to the threat placed by infectious diseases on humans’ survival, it is suggested that humans have a behavioral and physiological immune system. The behavioral immune system is said to be motivated by the emotion of disgust and serves to prevent entry of pathogens, whilst the physiological immune system serves to neutralize invading pathogens. While often studied disparately, over the past decade researchers have started to examine the reciprocal relationship between the behavioral immune system (disgust) and the physiological immune system. Two relationships have been advanced in the literature. The first relationship, termed the complementary relationship, suggests that exposure to a core (pathogen-related) disgust may facilitate a preparatory immune response. The second relationship, termed the compensatory prophylaxis hypothesis, suggests that lower levels of physiological immune function may be compensated for (and in turn relate to) greater behavioral immune function (e.g., higher disgust sensitivity)—and vice versa. The aim of this current chapter then, is to provide an overview of the theory and research related to understanding the reciprocal relationship between disgust and the physiological immune system, as well as noting future directions for the field, and implications that understanding this relationship may afford.