Margolis R H, Dubno J R, Hunt S M
J Speech Hear Res. 1981 Sep;24(3):336-44. doi: 10.1044/jshr.2403.336.
Three experiments were conducted to investigate the detectability of tonal signals simultaneously presented with computer-generated, long duration (.5 sec), band-reject maskers. In Experiment 1, detectability of a tone of 500, 1000, or 2000 Hz presented at 50 dB SPL was measured as a function of the width of a spectral "notch" symmetrically placed around the tone. A narrow notch resulted in decreased detectability relative to the wide band (zero-notch width) control condition. Further increases in notch width resulted in increased detectability until subjects approached errorless performance. In Experiment 2, psychometric functions were obtained for a 1000-Hz tone presented in four notch-noise conditions. The slopes of the psychometric functions were consistently steeper in the band-reject conditions relative to the zero notch-width condition. These slope differences result in relationships between threshold and notch width that depend upon the region of the psychometric function from which the threshold estimates are obtained. In Experiment 3, the decrease in performance associated with the notch was found to increase in proportion to notch depth. The data suggest that spectral edges placed in the immediate vicinity of a tone reduce the detectability of the tonal signal. This "edge effect" is discussed in relation to two-tone inhibition that has been observed in the auditory nerve.
进行了三项实验，以研究与计算机生成的、持续时间较长（0.5秒）的带阻掩蔽器同时呈现的音调信号的可检测性。在实验1中，测量了以50 dB SPL呈现的500、1000或2000 Hz音调的可检测性，作为围绕该音调对称放置的频谱“陷波”宽度的函数。相对于宽带（零陷波宽度）对照条件，窄陷波导致可检测性降低。陷波宽度的进一步增加导致可检测性增加，直到受试者接近无差错表现。在实验2中，获得了在四种陷波噪声条件下呈现的1000 Hz音调的心理测量函数。相对于零陷波宽度条件，带阻条件下心理测量函数的斜率始终更陡。这些斜率差异导致阈值与陷波宽度之间的关系取决于从中获得阈值估计的心理测量函数区域。在实验3中，发现与陷波相关的性能下降与陷波深度成比例增加。数据表明，置于音调紧邻区域的频谱边缘会降低音调信号的可检测性。结合在听神经中观察到的双音抑制来讨论这种“边缘效应”。
