Evidence for A. J. Fridlund's (e.g.. 1994) "behavioral ecology view" of human facial expression comes primarily from studies of smiling in response to positive emotional stimuli. Smiling may be a special case because it clearly can, and often does serve merely communicative functions. The present experiment was designated (a) to assess the generalizability of social context effects to facial expressions in response to negative emotional stimuli and (b) to examine whether these effects are mediated by social motives, as suggested by the behavioral ecology view. Pairs of friends or strangers viewed film clips that elicited different degrees of sad affect, in either the same or a different room; a control group participated alone. Dependent variables included facial activity, subjective emotion, and social motives. Displays of sadness were influenced by stimulus intensity and were lower in all social conditions than in the alone condition. Unexpectedly, social context effects were also found for smiling.