Evolutionary perspectives on social bonding assert that individuals will best survive and thrive when they have close relationships with others who are responsive to their needs and invested in their welfare. However, it is unclear if and how individuals identify and select caring romantic partners at the relationship initiation phase. The present research integrates prior work and methods from two often distinct literatures (close relationships in social psychology and mating psychology) to test the following hypotheses: (a) there are cues to kindness or caregiving that can be reliably assessed by multiple perceivers; (b) these cues reflect meaningful information about the kindness or caregiving capacity of the targets (i.e., they are accurate); and (c) these cues influence romantic attraction, in both short-term and long-term contexts.

In two face perception studies (N = 413), participants viewed photographs of the other sex and rated them on a number of evolutionarily relevant traits (e.g., kindness, dominance, physical attractiveness) as well as their desirability as a one-time sex partner, dating partner, or spouse. Results indicate that kindness can be assessed both reliably and accurately (as indexed by either behavioral codes of responsiveness from actual support interactions in Study 1, or self and partner ratings of kindness and support in Study 2), and that perceptions of kindness are a unique predictor of short-term and long-term romantic attraction, even controlling for other features known to influence attraction. Rater sex was an important moderator; female targets were assessed for kindness more accurately than male targets, by both male and female raters.

In addition, both men and women preferred higher levels of kindness for all types of attraction, though the inclusion of other covarying traits moderated the strength of this relationship. Taken together, these results support the need for more targeted investigation into the role perceptions of and preferences for kindness play in mate selection processes.