The behavioral immune system is designed to avoid infected individuals, not outgroups

What is the adapted structure of the behavioral immune system? By definition, the behavioral immune system motivates pathogen avoidance. One prominent suggestion is that the behavioral immune system also contains an additional component that generates motivation to avoid individuals from unfamiliar outgroups. The evolvability of this component has recently been questioned, however, and it has been noted that all supportive evidence stems from WEIRD samples. In this paper, we conducted between-subject experiments in large samples of adult residents of the USA (N = 1615) and India (N = 1969). In the experiment, we measured comfort with physical contact with a depicted individual. The individual was either from an ethnic ingroup or outgroup and either showed a pathogen cue or not. Results were inconsistent with the view that the behavioral immune system motivates the avoidance of individuals from unfamiliar outgroups. Instead, the results strongly supported that the system simply motivates the avoidance of any infected individual regardless of their group membership.