We conduct a real-effort task experiment where subjects’ performance translates into a donation to a charity. In a within-subjects design we vary the visibility of the donation (no/private/public feedback). Confirming previous studies, we find that subjects’ performance increases, that is, they donate more to charity, when their relative performance is made public. In line with the competitive altruism hypothesis, a biology-based explanation for status-seeking behavior, especially male subjects increase performance in the public setting.