Happy faces are habituated more slowly by infants of depressed mothers.

Three-month-old infants of depressed (n=16) and non-depressed mothers (n=16) were habituated to video clips of a female model reciting phrases while posing happy or sad facial/vocal expressions and dishabituated to the alternate expressions. Overall, infants of depressed mothers took longer to habituate the video clips compared to infants of non-depressed mothers, and those assigned to habituate the sad video clips displayed a novelty response or dishabituated to the happy expressions. These findings suggest that 3-month-old infants of depressed mothers discriminate sad from happy expressions, however, they do not appear to perceive sad expressions as novel.