CHANGES IN INFANTS CRIES AS A FUNCTION OF TIME IN A CRY BOUT

The present study examines changes in cry sounds over the course of a relatively long bout of crying. Specifically, differences in acoustic characteristics of 5 cries from early and 5 cries from late in a prolo nged cry bout were assessed. The results indicated that several featur es changed in means and/or variances between early and late in the bou t. A subset of 9 acoustic features was chosen to evaluate changes in t he interrelations of features over time. Cries from late in the bout a ppeared to result from a smaller number of factors, which were more re adily interpretable in terms of a standard model of cry production. Th us, it appears that as infants' level of arousal or distress changes, so do the acoustic features of their cries. Further, the results suppo rt the notion that bouts of crying settle into a ''basic'' or regular cry whose acoustic features provide a reasonable match with a theoreti cal model of cry production.