Wright B A, McFadden D, Champlin C A
Department of Psychology, University of Florida, Gainesville 32611.
J Acoust Soc Am. 1993 Jul;94(1):72-82. doi: 10.1121/1.408215.
Delaying the onset of a signal relative to the onset of a simultaneous notched masker often improves the ability of subjects to "hear out" the signal at both threshold and suprathreshold levels. Viemeister and Bacon [J. Acoust. Soc. Am. 71, 1502-1507 (1982)] suggested that such signal-enhancement effects might be attributable to adaptation of the suppression directed from the masker to the signal, thereby releasing the signal from suppression. In support of their hypothesis, Viemeister and Bacon reported that a masker, preceded by an enhancer having no component at the signal frequency, produced more forward masking than did the masker by itself. Here the masker enhancement described by Viemeister and Bacon, signal enhancement, and two-tone suppression were measured in the same six subjects. Parametric manipulations of the masker-enhancement stimulus produced results similar to those previously reported for parallel investigations of signal enhancement, indicating that the two types of enhancement are closely related effects. Although the present data reveal an inverse relationship between the amounts of suppression and enhancement, suggesting that the two processes may be interrelated, no support was obtained for the hypothesis that adaptation of suppression can account for enhancement.
相对于同时呈现的带凹口掩蔽声的起始时刻延迟信号的起始时刻，通常会提高受试者在阈值和阈上水平“分辨出”信号的能力。维梅斯特和培根[《美国声学学会杂志》71, 1502 - 1507(1982)]提出，这种信号增强效应可能归因于从掩蔽声指向信号的抑制作用的适应性变化，从而使信号从抑制中释放出来。为支持他们的假设，维梅斯特和培根报告称，在一个掩蔽声之前呈现一个在信号频率处没有成分的增强声，会比掩蔽声单独呈现时产生更多的前掩蔽。在此，对维梅斯特和培根所描述的掩蔽声增强、信号增强以及双音抑制在相同的6名受试者中进行了测量。对掩蔽声增强刺激进行参数操作所产生的结果与先前对信号增强的平行研究所报告的结果相似，这表明这两种增强类型是密切相关的效应。尽管目前的数据揭示了抑制量与增强量之间的反比关系，这表明这两个过程可能相互关联，但对于抑制的适应性变化能够解释增强这一假设，并未获得支持。
