Personality, Parasites, Political Attitudes, and Cooperation: A Model of How Infection Prevalence Influences Openness and Social Group Formation

Abstract

What is the origin of individual differences in ideology and personality? According to the parasite stress hypothesis, the structure of a society and the values of individuals within it are both influenced by the prevalence of infectious disease within the society's geographical region. High levels of infection threat are associated with more ethnocentric and collectivist social structures and greater adherence to social norms, as well as with socially conservative political ideology and less open but more conscientious personalities. Here we use an agent‐based model to explore a specific opportunities‐parasites trade‐off (OPTO) hypothesis, according to which utility‐maximizing agents place themselves at an optimal point on a trade‐off between (a) the gains that may be achieved through accessing the resources of geographically or socially distant out‐group members through openness to out‐group interaction, and (b) the losses arising due to consequently increased risks of exotic infection to which immunity has not been developed. We examine the evolution of cooperation and the formation of social groups within social networks, and we show that the groups that spontaneously form exhibit greater local rather than global cooperative networks when levels of infection are high. It is suggested that the OPTO model offers a first step toward understanding the specific mechanisms through which environmental conditions may influence cognition, ideology, personality, and social organization.

Pathogen Load and the Nature of Ingroup Derogation: Evolution of Ingroup Derogation Based on the Sexual Penna Model

“…Plenty of studies have simulated the evolution of ingroup bias within the framework of cooperation or altruism. They consistently reported the prevalence of infectious disease within the society's geographical region could influence the evolution of cooperation and the formation of social groups within social networks [24]. Our study also found that the ingroup bias can be evolved in the case of low prevalence of infectious disease within ingroups which supports the hypothesis that ingroup bias is an adaptation to the disease threat posed by outgroup members.…”

A Price Paid for Our Internal Strife: Escalated Intragroup Aggression and the Evolution of Ingroup Derogation

“…Such environmental varieties make it quite possible for our ancestors to face the ecological condition in which ingroup investment is not optimal and should be reduced ( Thornhill and Fincher, 2014 ). Simulation studies also suggest that ingroup derogation would be evolved if ingroup cooperation has collapsed or it is more beneficial to cooperate with outgroup members ( Fu et al, 2012 ; Brown et al, 2016 ).…”

Future Global Change and Cognition

“…First, many of the articles reflect, in one way or another, the fact that climate change is politically and ideological contested. Thus, there is concern with “skepticism,” or more accurately denial, of climate science: Torcello () reflects on the ethics of denial; Ranney and Clark () and McCright, Charters, Dentzman, and Dietz () examine the effect of denial on the public; Brown, Fincher, and Walasek () seek to explain the underlying variables that cause people to acquire the worldviews that render them particularly receptive to denial.…”

“…Being explicit about the extent of uncertainty thus helps limiting its potentially adverse effect on people's trust in projections. Brown et al (2016) take up another fundamental issue that permeates much of the work on climate change in the cognitive sciences; namely, the role of personal worldviews and ideology. Rather than examining its effects, Brown and colleagues seek to explain the origins of individual differences in ideology.…”