The costs and benefits of kindness

What makes an act kind? Previous research found that kindness is the principal criterion on which individuals evaluate and choose social partners, but little research has explored how individuals assess the kindness of actions. Here we investigate the relationship between perceived benefit, cost, cost-benefit ratio and kindness in a large sample of real-world acts. In Study 1, participants (n = 15,997) rated 1,692 acts toward family, friends, colleagues and strangers. Results showed that benefit predicts kindness for all recipients, and cost predicts kindness for all recipients but strangers. In Study 2, participants (n = 4,801) rated 385 acts toward a generic 'someone'. Results showed that perceived benefit, and to a lesser extent cost, predicted kindness. The cost-benefit ratio was not a substantial positive predictor in either study. We discuss the implications of these findings for theories of kindness and how this method could be used to investigate related prosocial concepts.