Although strangers can assess certain traits of unacquainted others with moderate validity, overall validity is low. Differential validity across traits may be due to (a) the extent to which targets display valid cues or (b) the extent to which perceivers validly use cues. A functionalist perspective suggests that valid cue utilization should vary with how important the consequences of accurate trait assessment are. It was predicted from this perspective that perceivers would judge strangers' socio-sexuality more accurately than 3 other traits-social potency, social closeness, and stress reaction. Perceivers viewed 1-min videotaped segments of targets being interviewed and rated them on the 4 traits. Ratings were correlated with target-reported trait measures. As predicted, perceivers' ratings of male sociosexuality agreed relatively well with self-reports. This effect was moderated by sex of target and sex of perceiver.