Willingness to physically protect, independent of the ability to do so, guides social decision-making

Physical violence was a recurrent selection pressure in ancestral social environments. The psychology of partner choice may have partially been shaped by this. Here, we investigate whether people prefer partners who are willing and able to protect them from violence. In a series of 7 studies (N = 4,508), we systematically varied the willingness and ability of a date or friend to physically protect you from a violent attack, compared to scenarios in which you do not have this information. Independent of their physical strength (ability to protect), discovering that a person is willing to protect you greatly increased their attractiveness as a partner; this held for both women and men, and when evaluating both opposite- and same-sex partners of both sexes. In fact, partners who were willing to protect you were attractive even if they tried to do so but failed, and even if you were harmed because of their failure. Discovering that a partner is unwilling to protect you decreased their attractiveness. However, this effect varied with the sex of raters (greater decrease for women versus men) and targets (greater decrease for male than female targets); moreover, the decrease was greater for dates than friends. Indeed, discovering that a male date was unwilling to protect them was a deal-breaker for women. We found only weak evidence that ability to physically protect, independent of willingness, increases the attractiveness of a date or friend. We discuss the implications of this ancestrally evolved psychology for social decision-making in the modern world.