To avoid or not to avoid? The influence of kinship on the behavioral defense against infectious diseases

Infectious diseases have always been and still are a major cause of human death, causing fatal epidemics worldwide.

This project aims to resolve the paradox that while the most effective defense strategy would be to avoid every sick individual, humans do not; instead, some sick individuals are approached for caregiving purposes.

In fact, most care needs are met by family members, suggesting that kin selection strongly affects human responses to sickness cues.

This interdisciplinary project will be the first to address whether early facial cues of sickness influence humans’ decisions to avoid or approach (i.e. care for) sick individuals and to what degree kinship moderates such decisions.

In study 1, we will establish whether facial photographs of sick individuals induce spatial and social avoidance by using novel methods from experimental psychology and economics.

In study 2, we will use cutting-edge digital morphing techniques to experimentally increase facial resemblance, and establish whether this cue of kinship suppresses avoidance of sick kin or even induces an approach behavior.

In study 3, we will investigate whether the mere sight of early sickness cues activates the immune system, a mechanism that may enable approach, especially caregiving, by preparing the human body for an infectious attack.

This project will answer fundamental questions of human behavioral immunity, a field that will benefit a world whose inhabitants are increasingly at risk from pandemics.