Effects of social learning on mate preferences have been observed in a wide range of animal species, including humans. However, it is not known whether social learning also influences other important aspects of social perception in humans. We investigated whether ‘eavesdropping’, a form of social learning whereby observers extract information about individuals’ qualities by observing their interactions with others, influences men’s perceptions of the dominance of potential rivals. We found that observing the responses of other individuals modulates the perceived dominance of aggressors. Observers rated aggressors’ dominance higher when they had previously observed others responding to the aggressor in a fearful, intimidated manner than when they had observed others responding to the aggressor in an angry, aggressive manner. By contrast with this finding for rated dominance, observing identical interactions did not affect observers’ perceptions of the trustworthiness of the aggressors. The effect of observing others’ responses on the perceived dominance of aggressors demonstrates that eavesdropping influences perceptions of dominance rank among men, which would be adaptive if it reduces the costs (e.g. risk of serious injury and/or loss of resources) that may be associated with acquiring knowledge of others’ dominance rank via exclusively self-reliant learning. While previous research on social learning and sexual selection has focused on intersexual interactions (i.e. mate choice copying effects), our findings suggest that eavesdropping may also influence sexual selection for male traits via intrasexual competition.