Influence of acoustic experience on the ontogeny of frequency generalization gradients in the chicken.

Abstract

The role of auditory experience in the ontogeny of perceptual coding was investigated in hatchling chickens. In Experiment 1, auditory frequency generalization gradients were determined by using a habituation-generalization paradigm and an orienting response. One-day and 3-4-day chicks were habituated to 800-Hz tones and then tested at five frequencies ranging from 800 to 1,000 Hz. One-day chicks displayed reliably flatter generalization gradients-than 3-4-day chicks. In Experiment 2 an auditory deprivation method is described in which an ear impression compound was injected into the external ear. This method (a) is fully calibrated and provides approximately 40 dB of attenuation across a .125-to 4.0-kHz range, (b) appears to be fully reversible, and (c) is applicable prior to normal auditory experience as well as at subsequent stages. In Experiment 3, this method was used to investigate the effects of auditory deprivation on the "perceptual sharpening" described in Experiment 1. Chicks were deprived from Embryonic Day 184 to 3-4 days posthatch, at which time normal, deprived, and shamoperated chicks were tested as in Experiment 1. The generalization gradients of the deprived chicks were significantly flatter than, those of the 3-4 day normal and sham-operated chicks and were similar to those of 1-day chicks. This effect cannot be attributed to (a) operative procedures, (b) changes in auditory thresholds, or (c) changes in response rate with age or condition. Thus the perceptual sharpening normally occurring between 1 and 3-4 days posthatch fails to occur during that time in the absence of a normal acoustic environment. According to one view, both perceptual thai, 1975), and fewer stimulus classificaand cognitive development involve responses tions are made by younger children than to increasingly specific environmental stim-by older children (

Afferent influences on brain stem auditory nuclei of the chicken: Neuron number and size following cochlea removal

“…Average thresholds from stimulation of the TTX-injected side are compared to those from stimulation of the normal ear in Figure 3. At all frequencies tested, the thresholds ipsilateral and contralateral to TTX injection were identical and were comparable to those found in other studies of the chick (Saunders et al, 1973;Kerr et al, 1979;Rebillard and Rubel, 198 1;Tucci and Rubel, 1985).…”

Development of responsiveness to suprathreshold acoustic stimulation in chickens.

“…H/ The selection of these values was based on previous data (Kerr et al, 1979) The Mid range includes frequencies in the chickens' maternal assembly call and partially replicates the Kerr el al study. The frequencies of High and Low ranges were selected in order that the thresholds of brain stem evoked potentials at these frequencies are roughly equal and noticeably higher than the thresholds of the frequencies in the Mid range (Kerr et al , 1979) Pairs of frequencies differ b\ 6'. ; because the results of Kerr et al suggested that older chicks would respond to a ti r r change and \ounger chicks would not The highest and lowest 1 requeue ies within each range differ by 25 r t. primanK for consistency…”

“…One interpretation of these data is that the animals become progressively more able to distinguish changes along a single perceptual dimension from general changes in acoustic stimulation. The role of early experience in this "learning" is, at present, unknown, but the work of many investigators predicts that experiences with frequency shifts are necessary for the animals to separate this dimension from other dimensions (Gans, 1968;Gottlieb, 1971aGottlieb, , 1976Kerr et al, 1979;Lashley & Wade, 1946;Peterson, 1962;Tees, 1976;Tracy, 1970).…”

“…Gibson, 1969). Rubel and Rosenthal (1975) and Kerr, Ostapoff, and Rubel (1979) showed that 1-day-old chicks, for example, had flatter frequency generalization gradients following habituation to pure-tone stimuli than did 4-day-old chicks. Other animal studies have shown the same age-related sharpening in preferences (Bateson, 1971;Gray & Tardif, 1979;Hailman, 1967;Lehrman & Rosenblatt, 1971), in discrimination (Zolman & Becker, 1968), and possibly in neuronal responses (Aitkin & Moore, 1975;Carlier, Le-188 noir, & Pujol, 1979;Grobstein & Chow, 1976;Mistretta & Bradley, 1978).…”

“…Rubel (1970), for example, showed that exposure of young quail to a stimulus on which they had been "imprinted" resulted in cessation of distress vocalizations (peeps). More recently, Kerr et al (1979) showed that young chickens peep nearly incessantly when alone in a well-lit temperate chamber and that changes in the acoustic environment often cause a momentary suppression of these ongoing peeps. This suppression habituates quickly but can be reinstated by other stimulus changes.…”