Discrimination of infants' cry-signals.

A technique for clustering infants' cry-signals on the basis of perceptually discriminable acoustic characteristics is reported. A cry-sequence containing all pairwise combinations of 24 signals was constructed. These signals have been used previously in cry-recognition studies (e.g., Wasz-Hockert, et al., 1968) and consist of six each of pain, hunger, pleasure, and birth. 20 musically competent subjects were tested individually and instructed to compare each cry with the one immediately preceding it in the sequence. Forced-choice "similarity" scores were summed for every pair of cries. These "similarity scores" were data for both a manual and a computerized clustering method. There was absolute agreement between these two methods, and the clusters of cry-signals correspond very closely to the four original cry groups. This seems a valid technique for examining the acoustic similarity of infants' cry-signals.