Maternal Sensitivity and the Learning-Promoting Effects of Depressed and Non-Depressed Mothers' Infant-Directed Speech.

The hypothesis that aspects of current mother-infant interactions predict an infant's response to maternal infant-directed speech (IDS) was tested. Relative to infants of non-depressed mothers, those of depressed mothers acquired weaker voice-face associations in response to their own mothers' IDS in a conditioned-attention paradigm, although this was partially attributable to demographic differences between the two groups. The extent of fundamental frequency modulation (DeltaF(0)) in maternal IDS was smaller for infants of depressed than non-depressed mothers, but did not predict infant learning. However, Emotional Availability Scale ratings of maternal sensitivity, coded from videotapes of mothers and infants engaged in a brief play interaction, were significant predictors of infant learning, even after maternal depression, its demographic correlates, and antidepressant medication use had been taken into account. These findings are consistent with a role for experience-dependent processes in determining IDS's effects on infant learning.