Implications of the behavioural immune system for social behaviour and human health in the modern world

Abstract

The ‘behavioural immune system’ is composed of mechanisms that evolved as a means of facilitating behaviours that minimized infection risk and enhanced fitness. Recent empirical research on human populations suggests that these mechanisms have unique consequences for many aspects of human sociality—including sexual attitudes, gregariousness, xenophobia, conformity to majority opinion and conservative sociopolitical attitudes. Throughout much of human evolutionary history, these consequences may have had beneficial health implications; but health implications in modern human societies remain unclear. This article summarizes pertinent ways in which modern human societies are similar to and different from the ecologies within which the behavioural immune system evolved. By attending to these similarities and differences, we identify a set of plausible implications—both positive and negative—that the behavioural immune system may have on health outcomes in contemporary human contexts. We discuss both individual-level infection risk and population-level epidemiological outcomes. We also discuss a variety of additional implications, including compliance with public health policies, the adoption of novel therapeutic interventions and actual immunological functioning. Research on the behavioural immune system, and its implications in contemporary human societies, can provide unique insights into relationships between fitness, sociality and health.

The sociality–health–fitness nexus: synthesis, conclusions and future directions

“…Interesting new angles on this question were raised in this theme issue, including social immunity in insects [9] and the behavioural immune system in humans [12]. Yet other questions arise.…”

“…In summary, within highly social mammal speciesincluding humans-social interaction appears to be associated with a health-related trade-off that is highlighted across several articles in this theme issue [5,11,12]. On the one hand, increased social contact may increase individual organisms' exposure to infectious diseases [12].…”

“…On the one hand, increased social contact may increase individual organisms' exposure to infectious diseases [12]. On the other hand, increased social contact with conspecifics is associated with more effective immunological and behavioural responses to infection and with better long-term health outcomes [5,11].…”

“…Some of these studies have focused on individuals' behavioural traits (e.g. cross-national differences in extraversion [12,38]). Others have focused on formal institutions and informal social structures that help to define the nature of human societies [39].…”

“…This breadth is important because, for many of these topics, clear implications exist for understanding human health and behaviour, for example in relation to social contact and various chronic diseases throughout the life course [11], or in terms of how disease influences individual psychology, which can have far-reaching population-level consequences [12]. Indeed, an important take-home message from this theme issue is that understanding the links between health, fitness and sociality in broad comparative perspective has important implications for understanding human health-a point that others have also made [13][14][15].…”