Gray L
Department of Otolaryngology-Head and Neck Surgery, University of Texas Health Science Center at Houston 77030.
Hear Res. 1993 Sep;69(1-2):83-90. doi: 10.1016/0378-5955(93)90095-i.
Simultaneous masking was used to investigate the development of frequency analysis in newborn animals. The ability of young chickens to detect a tone in the presence of a second tone was measured. In the first experiment data were collected with a 500-Hz masker presented at 15 or 25 dB above absolute threshold. Signals to be detected varied up to an octave from the masker (+/- 1/9, +/- 2/9, +/- 1/3, +/- 2/3, and -1 octave). Receiver operating characteristics (ROCs) were constructed from delays in ongoing peeps that occur when chicks detect the presence of the signal over the masker. Psychometric functions were fit by probit analysis using areas under these ROCs. Amounts of masking were estimated by the degree to which psychometric functions were shifted toward the right by the presence of the masker. There is no developmental change in these masking patterns, corroborating recent data from human infants. Masking was shown in a second experiment to be similar at a higher frequency (given intensities corrected for improving absolute thresholds). In conclusion, masking patterns derived from chicks' peeps are like those from adult humans. Frequency analysis, as measured by simultaneous masking, appears to be mature in chickens at hatching.
同时掩蔽被用于研究新生动物频率分析的发展。测量了幼鸡在存在第二个音调的情况下检测一个音调的能力。在第一个实验中，使用在高于绝对阈值15或25分贝的情况下呈现的500赫兹掩蔽音来收集数据。待检测的信号与掩蔽音的频率相差高达一个八度（±1/9、±2/9、±1/3、±2/3和 -1个八度）。根据小鸡检测到掩蔽音之上信号存在时正在进行的啁啾声中的延迟构建接收器操作特性（ROC）曲线。使用这些ROC曲线下的面积通过概率分析拟合心理测量函数。通过掩蔽音的存在使心理测量函数向右移动的程度来估计掩蔽量。这些掩蔽模式没有发育变化，这证实了最近来自人类婴儿的数据。在第二个实验中表明，在更高频率下掩蔽情况相似（给出了针对改善绝对阈值进行校正的强度）。总之，从小鸡啁啾声得出的掩蔽模式与成年人类的相似。通过同时掩蔽测量的频率分析在孵化时的小鸡中似乎已经成熟。
