Acoustic correlates of adults\u27 perceptions of infant distress

This study examined temporal changes in acoustic features of 4-min-long long cry bouts given by hungry, 1-m-old infants (N = 20) and the relation over time between acoustics and adults\u27 ratings of infant distress. Two listeners rated distress at 10-s intervals, and acoustic features of each 10-s segment were analyzed. As expected, distress ratings, the amount of dysphonation (screaming) within the wails, and the frequency of wails within the segments increased from the first to the second halves of the cry bouts, whereas the duration of pauses between wails decreased. Further, distress ratings became less variable over time. Increased ratings of infant distress over time were related to more dysphonation, more frequent wails, and shorter pauses between wails. Analysis of each half of the cry bouts revealed a stronger relation between ratings and dysphonation in the first half than in the second, and a greater contribution of number of wails to the prediction of distress ratings in the first half. Examination of each infants\u27 data showed marked differences among individuals in the relations between ratings and each acoustic feature. The results show that the infant\u27s cry is a dynamic acoustic signal, and that adults\u27 cry perceptions are just as dynamic. The increased stability over time of the cry ratings, but not of the acoustics, suggests that listeners may calibrate their perceptions to crying early in the bout, making them less susceptible over time to acoustic variations in the cry. Further, the differences among the relations between ratings and acoustics for individual infants suggest that listeners may calibrate their cry perceptions to infants whose cries are familiar. These results highlight the importance of considering the cry, and its perception, as dynamic processes that not only change during a bout, but also may change as adults become familiar with particular infants\u27 cries.