Beware the foe who feels no pain: Associations between relative formidability and pain sensitivity in three U.S. online studies

Pain is a critical internal regulator of current and future behavior. However, pain also constitutes a tactical liability in agonistic interpersonal conflict. Therefore, information about the pain sensitivity of others should play a functional role in assessments of the formidability of prospective foes or allies. Compared to an individual known to be sensitive to pain, an individual known to be insensitive to pain should be assessed as more formidable, as it would be more difficult to deter the latter from aggressing, and more difficult to motivate them to desist should conflict erupt. Further, knowing that a potential antagonist is armed should lead observers to infer relative insensitivity to pain, as the costs of erroneously presuming that an armed individual is sensitive to pain – and thus is both more vulnerable and less likely to aggress – will generally be higher than the costs of erroneously presuming that they are insensitive to pain, and thus are both less vulnerable and more inclined to aggress. Here, we find support for these predictions in three pre-registered studies conducted with U.S. online crowdsource workers (N = 473; N = 204; N = 301). The intimate association between information regarding pain sensitivity and the process of formidability assessment has implications for a variety of pressing social issues, from the use of excessive force by police, to discriminatory racial biases in the provision of medical care.