Anthony J. DeCasper

Contingencies of Stimulation: Effects on Learning and Emotion in Neonates*

One group of four infants could produce vocal music only by appropriately spacing bursts of nonnutritive sucking. Within 24 hours the same singing was presented independent of sucking. A second group of four infants encountered a reverse order of conditions: noncontingent singing occurred first, followed by response-contingent presentation. Infants exposed to contingent singing first learned to space sucking bursts, but infants having previous noncontingent experience did not learn to do so. Moreover, noncontingent singing was upsetting to infants having prior contingent experience, but was not upsetting when it occurred first. This pattern of results was predicted by, and thus supports, a contingency view of operant learning. Contingency theories may be more useful than the traditional contiguity view for understanding newborn behavior.

The intrauterine heartbeat: A potent reinforcer for newborns.

Intrauterine hwxtbeot sounds effectively reinforced human newborns’ responding in on operant learning task. Reinforcing only those sucking bursts that followed short intervals since the lost burst increased the relative frequency of short intervals, and reinforcing only those long intervals occurring between bursts increased the frequency of long ones. These results support the evidence suggesting that in-utero auditory experience affects postnotol behavior in humans. neonates auditory perception prenatal experience maternal heortbeot learning

A melodic contour repeatedly experienced by human near-term fetuses elicits a profound cardiac reaction one month after birth.

Background Human hearing develops progressively during the last trimester of gestation. Near-term fetuses can discriminate acoustic features, such as frequencies and spectra, and process complex auditory streams. Fetal and neonatal studies show that they can remember frequently recurring sounds. However, existing data can only show retention intervals up to several days after birth. Methodology/Principal Findings Here we show that auditory memories can last at least six weeks. Experimental fetuses were given precisely controlled exposure to a descending piano melody twice daily during the 35th, 36th, and 37th weeks of gestation. Six weeks later we assessed the cardiac responses of 25 exposed infants and 25 naive control infants, while in quiet sleep, to the descending melody and to an ascending control piano melody. The melodies had precisely inverse contours, but similar spectra, identical duration, tempo and rhythm, thus, almost identical amplitude envelopes. All infants displayed a significant heart rate change. In exposed infants, the descending melody evoked a cardiac deceleration that was twice larger than the decelerations elicited by the ascending melody and by both melodies in control infants. Conclusions/Significance Thus, 3-weeks of prenatal exposure to a specific melodic contour affects infants ‘auditory processing’ or perception, i.e., impacts the autonomic nervous system at least six weeks later, when infants are 1-month old. Our results extend the retention interval over which a prenatally acquired memory of a specific sound stream can be observed from 3–4 days to six weeks. The long-term memory for the descending melody is interpreted in terms of enduring neurophysiological tuning and its significance for the developmental psychobiology of attention and perception, including early speech perception, is discussed.