Human threat management systems: self-protection and disease avoidance.

Humans likely evolved precautionary systems designed to minimize the threats to reproductive fitness posed by highly interdependent ultrasociality. A review of research on the self-protection and disease avoidance systems reveals that each system is functionally distinct and domain-specific: each is attuned to different cues; engages different emotions, inferences, and behavioral inclinations; and is rooted in somewhat different neurobiological substrates. These systems share important features, however. Each system is functionally coherent, in that perceptual, affective, cognitive, and behavioral processes work in concert to reduce fitness costs of potential threats. Each system is biased in a risk-averse manner, erring toward precautionary responses even when available cues only heuristically imply threat. And each system is functionally flexible, being highly sensitive to specific ecological and dispositional cues that signal greater vulnerability to the relevant threat. These features characterize a general template useful for understanding not only the self-protection and disease avoidance systems, but also a broader set of evolved, domain-specific precautionary systems.