Authors suggest that in a majority of studied societies, kin of the deceased tend to engage ritually in risky prolonged and intimate preparation behaviors with corpses. This occurs namely in visual exposure and tactile interaction. Authors hypothesize that this extended contact not only allows true confirmation of death (through exposure to many cues), but also facilitates acceleration of a grieving process that returns the bereaved to a normal state of social functioning.

Using 57 cultures from the Human Relations Area Files database, this paper examines the function and effectiveness of the belief of punitive ancestors in small-scale societies. The authors found that belief in dangerous ancestral entities is widespread and common and that harm is preventable through ritualized mortuary practices. The authors concluded that the fear of ancestral spirits did not promote social cooperation or inhibit self-interest behavior, contrary to the supernatural punishment hypothesis.

In order to evaluate an adaptive justification for restriction of ritualized physical contact, the authors test association between three manifestations of physical interaction and prevalence of pathogens cross-culturally. Their expectation, supported by two of the three tested hypotheses, is that higher pathogen prevalence will lead to customs of restricted physical contact. Both cultural and biological evolution are suggested to be influential in selecting for physically intimate behaviors.