Moore B C, Glasberg B R, Roberts B
J Acoust Soc Am. 1984 Oct;76(4):1057-66. doi: 10.1121/1.391425.
Four experiments were performed in an attempt to refine the measurement of psychophysical tuning curves (PTCs). PTCs were determined using sinusoidal signals and narrow-band noise maskers, in both simultaneous and forward masking. In experiment I a fixed low-level notched noise was gated with the masker in order to restrict off-frequency listening and to eliminate "confusions" between the signal and masker in forward masking. In contrast to previous work, this procedure produced PTCs with similar round tips in both simultaneous and forward masking. The PTCs differed mainly in that the high-frequency skirts were steeper in forward masking. Experiment II compared PTCs with and without an additional notched-noise masker, for a number of signal levels. The notched noise had the effect of broadening the tips of the PTCs, this effect being greater in forward masking than in simultaneous masking. With increasing signal level the high-frequency skirt of the PTC became slightly steeper, and the low-frequency skirt slightly shallower. Experiment III studied the effect of signal duration on PTCs determined in simultaneous masking. Duration had little effect when off-frequency listening was restricted with a fixed notched-noise masker, but had a substantial effect in the absence of such a masker. Experiment IV studied the effect of signal delay in forward masking. When off-frequency listening was restricted and the signal levels adjusted to produce similar masker levels at threshold for each delay, the shape of the PTC was not affected by delay. It is concluded that, when PTCs are determined in the presence of notched noise, suppression is probably responsible for most of the differences between simultaneous and forward masking. Previous work may have overestimated the influence of suppression, because it did not control off-frequency listening and/or provide appropriate detection cues in forward masking.
进行了四项实验，旨在优化心理物理调谐曲线（PTC）的测量。使用正弦信号和窄带噪声掩蔽器，在同时掩蔽和前掩蔽条件下测定PTC。在实验I中，固定的低电平陷波噪声与掩蔽器同时开启，以限制非频率聆听，并消除前掩蔽中信号与掩蔽器之间的“混淆”。与之前的研究不同，该程序在同时掩蔽和前掩蔽中均产生了具有相似圆形尖端的PTC。PTC的主要差异在于，前掩蔽中的高频边缘更陡峭。实验II比较了在多个信号电平下，有无额外陷波噪声掩蔽器时的PTC。陷波噪声使PTC的尖端变宽，前掩蔽中的这种效应比同时掩蔽中更大。随着信号电平增加，PTC的高频边缘略有变陡，低频边缘略有变浅。实验III研究了信号持续时间对同时掩蔽中测定的PTC的影响。当用固定的陷波噪声掩蔽器限制非频率聆听时，持续时间影响不大，但在没有这种掩蔽器时影响显著。实验IV研究了前掩蔽中信号延迟的影响。当限制非频率聆听并调整信号电平，使每个延迟下阈值处的掩蔽器电平相似时，PTC的形状不受延迟影响。得出的结论是，当在陷波噪声存在的情况下测定PTC时，抑制可能是同时掩蔽和前掩蔽之间大多数差异的原因。之前的研究可能高估了抑制的影响，因为它没有控制非频率聆听和/或在前掩蔽中提供适当的检测线索。
