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Biomedical subjects

G E Gustafson

Publications and source records attributed to G E Gustafson.

11 recordsLinked to original sources

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 prolonged cry bout were assessed. The results indicated that several features changed in means and/or variances between early and late in the bout. A subset of 9 acoustic features was chosen to evaluate changes in the interrelations of features over time. Cries from late in the bout appeared to result from a smaller number of factors, which were more readily interpretable in terms of a standard model of cry production. Thus, it appears that as infants' level of arousal or distress changes, so do the acoustic features of their cries. Further, the results support the notion that bouts of crying settle into a "basic" or regular cry whose acoustic features provide a reasonable match with a theoretical model of cry production.

Arousal↗

Robustness of individual identity in the cries of human infants.

This study investigated the possibility that one function of the human infant's cry is to convey individual identity across distance. Six-hundred adults, having been exposed to 30 s of an infant's crying, were asked to identify this infant on the basis of other, experimentally altered, cries. The cries were altered naturally by rerecording across distance in the out-of-doors, and artificially by bandpass filtering and temporal reorganization. The individuality of cries proved remarkably robust to degradation: Only when frequencies were limited to the range of 8 to 10 kHz was recognition performance significantly impaired. It is argued that the human infant's cry, a complex signal with multiple markers of individuality, may have among its functions the communication of infants' identities across distance.

Adolescent↗

On the importance of fundamental frequency and other acoustic features in cry perception and infant development.

This study examined acoustic correlates of adults' ratings of infants' cries. Parents and nonparents rated 12 spontaneous cries from young infants on 8 items describing the cries' aversiveness and on 9 semantic differential items. The results indicated that the duration, the amount of dysphonation, and proportion of energy in various frequency bands were highly correlated with adults' ratings. Further, the pattern of correlations between each of the 17 rating scale items and the acoustic attributes was virtually the same, suggesting that the items represented a single underlying dimension of perceived aversiveness. Finally, no differences were found between the results for parents and nonparents. General issues in the study of cry perception are discussed.

Acoustics↗

Acoustic correlates of individuality in the cries of human infants.

The acoustic features that differentiate the cries of individual human infants were examined in this study. A recognition task, performed by 400 nonparent adults, was used to classify twenty 30-day-old infants as easy or difficult to recognize on the sole basis of their tape-recorded cries. The cries of easy- vs difficult-to-recognize infants were then compared on measures of duration, fundamental frequency, peak frequency in the spectrum, signal-to-noise ratios, and energy in selected frequency bands. The results indicated that each of these measures differentiated the cries of easy- vs difficult-to-recognize infants. Such redundancy should make the cry robust to degradations of selected acoustic parameters, thus enhancing its ability to carry information about individual identity across distances.

Acoustics↗

Individual recognition of human infants on the basis of cries alone.

Human parents were asked to identify their infants on the basis of tape-recorded cries that they had not previously heard. The cries of twenty 30-day-old infants were recorded just prior to a feeding, then rerecorded onto a test tape containing cries from three other infants. Eighty percent of mothers were able to recognize their infants' cries, as were 45% of fathers. An additional 140 adults (non-parents) were tested in order to determine if the process of dubbing cries onto test tapes had left extraneous auditory cues to infants' identities and if the foil infants were equally discriminable. The results indicated that parents' recognition was not based on extraneous cues and that, overall, the foils were appropriate distractors in the parents' task. Thus, the majority of parents can recognize their 30-day-old infants on the sole basis of acoustic cues contained in the infants' cries. The acoustic features that underlie this recognition are now being investigated.

Auditory Perception↗

Infant crying and adults' anticipated caregiving responses: acoustic and contextual influences.

These studies assessed adults' latencies to signal that they would respond to infant crying as functions of (1) the degree of infant distress they perceived in the cry, and (2) contextual information relevant to caregiving. In the first study (N = 34), listeners waited longer to respond to cries that they had earlier rated as sounding less distressed than when they heard cries of higher distress. Further, those who had been told that the infant needed sleep waited longer to respond than those without this information. This effect of context information, however, was limited to the latencies; in another study (N = 50), listeners' ratings of distress were not affected. Several acoustic features of the cries correlated with distress ratings and with latencies to signal a caregiving response. Taken together, the results suggest that adults' responses to crying are influenced both by acoustic gradations in the cry itself and by the caregiving context. Ratings of degree of distress manifest in the cry, in other words, may be highly predictive of caregiving behavior but not wholly so. Finally, although certain acoustic variations related to greater perceived distress and speed of response, differences were apparent between infants in the magnitude of these variations. The implication that the general process of cry perception may be calibrated, or fine tuned, to the range of acoustic variation provided by individual infants is discussed.

Adult↗