Hedonic and social determinants of facial displays to odors

The facial responses of seven female subjects were videotaped while they smelled six odors in each of three experimental conditions (spontaneous, posing to real odors and posing to imagined odors). Videotaping was covert in the spontaneous condition and overt in the posed conditions. Raters (N = 65) were shown the videotapes and asked to judge whether the subjects smelled something unpleasant, neutral or pleasant. Raters were correct in only 37% of their judgements when the subjects were not aware of being observed. Raters' accuracy improved significantly when subjects posed to real odors (76% correct) and posed to imagined odors (76% correct). Faces made to unpleasant odors were classified more accurately than those to pleasant odors in all three conditions. These results cannot be accounted for by reflexive-hedonic accounts of odor-related facial expressions.