Cicchetti D, Sroufe L A
Child Dev. 1976 Dec;47(4):920-9.
A close association between affective expression and cognitive development was demonstrated in a longitudinal study of 14 Down's syndrome infants. It was found that the Down's syndrome infants laughed to groups of stimulus items in the same order as did previous samples of normal infants. Although the process was delayed by several months, the retarded babies too laughed first at physically intrusive items and only later to items calling for greater cognitive sophistication. In addition, cognitive developmental status, assessed by the Bayley and Uzgiris-Hunt scales, paralleled and was predicted by the level of affective development. Predictive and concurrent correlations between Bayley mental scores and various indices of affectivity ranged from .68 to .92. There was striking individual consistency across affective, mental, and motor measures, suggesting the organized nature of retarded development. Finally, since Down's syndrome infants frequently smiled under conditions when normal babies would laugh, a role for tension production, in addition to cognitive factors, was suggested in accounting for the behavior of these infants.
