Facial expression in adults with Down's syndrome.

The facial expressions of adults with Down's syndrome (DS; n = 15) as they watched happy, sad, and neutral videotapes were compared with those of a healthy age-matched control group (n = 20). Facial movements were analyzed with the Facial Action Coding System (P. E. Ekman & W. V. Friesen, 1978). While watching happy stimuli, the 10 DS adults who were able to appropriately rate their reactions smiled with a cheek raise as frequently as control adults, suggesting that the expression of positive affect in these individuals is normal. Contrary to predictions, however, the DS group exhibited fewer smiles without cheek raises than did control adults and were more likely not to smile. Neither group showed prototypic sad facial expressions in response to sad stimuli. Independent of emotion, DS participants made more facial movements, including more tongue shows, than did control participants. Differences in facial expression in DS adults may confuse others' interpretations of their emotional responses and may be important for understanding the development of abnormal emotional processes.