Moore B C, Vickers D A
Department of Experimental Psychology, University of Cambridge, England.
J Acoust Soc Am. 1997 Oct;102(4):2284-90. doi: 10.1121/1.419638.
This experiment was intended to clarify the relative role of spread of excitation and suppression in simultaneous masking, for masker frequencies just below and well below the signal frequency. The experiment had two stages. In stage 1, growth-of-masking functions were measured in simultaneous masking for a 2200-Hz sinusoidal signal and a sinusoidal masker with frequency of either 1800 Hz or 500 Hz. Straight lines fitted to these data were used to determine masker levels that would give 10, 20, and 30 dB of masking. In stage 2, thresholds for detecting a brief 2200-Hz signal were measured using forward masking. It was reasoned that the threshold of the signal would give an indication of the amount of excitation evoked by the masker in the frequency region of the signal. Three forward maskers were used: (1) a 2200-Hz sinusoid at 10, 20, or 30 dB sensation level (SL); (2) a 2200-Hz sinusoid at the same levels as in (1) together with a sinusoid with frequency 500 or 1800 Hz at a level just sufficient to mask the 2200-Hz sinusoid. We refer to this as the "combined masker," (3) a 500-Hz or 1800-Hz sinusoid at the same levels as in (2) above. The 1800-Hz combined masker produced slightly less forward masking than the 2200-Hz masker (1), which might be explained in terms of suppression or as perceptual cueing. Both the 1800-Hz combined masker and the 1800-Hz component alone (3) gave significant amounts of forward masking (up to 18 dB), indicating that these maskers produced substantial excitation at 2200 Hz. This is consistent with the idea that the simultaneous masking of the 2200-Hz component in stage 1 was produced by spread of excitation rather than by suppression. The 500-Hz combined masker produced much less forward masking than the 2200-Hz component alone, indicating strong suppression of the 2200-Hz component of the combined masker by the 500-Hz component. However, both the 500-Hz combined masker and the 500-Hz component alone produced some forward masking. This is not consistent with the idea that masking of the 2200-Hz component in stage 1 (simultaneous masking) was produced solely by suppression.
本实验旨在阐明对于低于信号频率及远低于信号频率的掩蔽声频率，兴奋扩散和抑制在同时掩蔽中的相对作用。该实验有两个阶段。在第一阶段，测量了2200赫兹正弦信号与频率为1800赫兹或500赫兹的正弦掩蔽声同时掩蔽时的掩蔽增长函数。用拟合这些数据的直线来确定能产生10分贝、20分贝和30分贝掩蔽的掩蔽声强度。在第二阶段，使用前向掩蔽测量检测短暂2200赫兹信号的阈值。据推测，信号的阈值将表明掩蔽声在信号频率区域所诱发的兴奋量。使用了三种前向掩蔽声：（1）感觉级（SL）为10分贝、20分贝或30分贝的2200赫兹正弦波；（2）与（1）中相同强度的2200赫兹正弦波，再加上一个频率为500赫兹或1 [此处原文有误，应为1800] 赫兹的正弦波，其强度刚好足以掩蔽2200赫兹正弦波。我们将此称为“组合掩蔽声”，（3）与上述（2）中相同强度的500赫兹或1800赫兹正弦波。1800赫兹组合掩蔽声产生的前向掩蔽比2200赫兹掩蔽声（1）略少，这可以用抑制或感知线索来解释。1800赫兹组合掩蔽声和单独的1800赫兹成分（3）都产生了显著的前向掩蔽（高达18分贝），表明这些掩蔽声在2200赫兹处产生了大量兴奋。这与第一阶段中2200赫兹成分的同时掩蔽是由兴奋扩散而非抑制产生的观点一致。500赫兹组合掩蔽声产生的前向掩蔽比单独的2200赫兹成分少得多，表明500赫兹成分对组合掩蔽声中的2200赫兹成分有强烈抑制。然而，500赫兹组合掩蔽声和单独的500赫兹成分都产生了一些前向掩蔽。这与第一阶段（同时掩蔽）中2200赫兹成分的掩蔽仅由抑制产生的观点不一致。
