Children's facial responsiveness to odors: Influences of hedonic valence of odor, gender, age, and social presence.

Facial responsiveness to pleasant and unpleasant odors was examined in 5- to 12 year-old children in either an alone condition ( AC ) or a social presence condition (SPC). The children failed to display reflex-like patterns, but they exhibited facial configurations that varied according to the odor valence and the social condition. Girls evinced more smiles than did boys, but this sex difference was significant only in response to unpleasant odors in the SPC. Furthermore, untrained observers were able to accurately identify the children's facial responses to unpleasant odors in the AC only and to pleasant odors in the SPC only. These findings (a) suggest that facial responsiveness to odors is flexible and able to reorganize when display rules operate and (b) support the emotional and communicative functions of human facial behavior.