Demany Laurent, Carlyon Robert P, Semal Catherine
Laboratoire Mouvement, Adaptation, Cognition UMR CNRS 5227, Universite de Bordeaux, Bordeaux, France.
J Acoust Soc Am. 2009 Feb;125(2):1082-90. doi: 10.1121/1.3050271.
Sek and Moore [J. Acoust. Soc. Am. 106, 351-359 (1999)] and Lyzenga et al. [J. Acoust. Soc. Am. 116, 491-501 (2004)] found that the just-noticeable frequency difference between two pure tones relatively close in time is smaller when these tones are smoothly connected by a frequency glide than when they are separated by a silent interval. This "glide effect" was interpreted as evidence that frequency glides can be detected by a specific auditory mechanism, not involved in the detection of discrete, time-delayed frequency changes. Lyzenga et al. argued in addition that the glide-detection mechanism provides little information on the direction of frequency changes near their detection threshold. The first experiment reported here confirms the existence of the glide effect, but also shows that it disappears when the glide is not connected smoothly to the neighboring steady tones. A second experiment demonstrates that the direction of a 750 ms frequency glide can be perceptually identified as soon as the glide is detectable. These results, and some other observations, lead to a new interpretation of the glide effect, and to the conclusion that continuous frequency changes may be detected in the same manner as discrete frequency changes.
塞克和摩尔[《美国声学学会杂志》106, 351 - 359 (1999)]以及利曾加等人[《美国声学学会杂志》116, 491 - 501 (2004)]发现，当两个时间上相对接近的纯音通过频率滑动平滑连接时，它们之间刚刚可察觉的频率差异比被静音间隔隔开时要小。这种“滑动效应”被解释为频率滑动可被一种特定听觉机制检测到的证据，该机制不参与离散的、有时间延迟的频率变化的检测。利曾加等人还认为，滑动检测机制在其检测阈值附近关于频率变化方向提供的信息很少。此处报道的第一个实验证实了滑动效应的存在，但也表明当滑动与相邻的稳定音调连接不顺畅时，该效应会消失。第二个实验表明，一旦可检测到750毫秒的频率滑动，其方向就能在感知上被识别。这些结果以及其他一些观察结果，导致了对滑动效应的一种新解释，并得出连续频率变化可能与离散频率变化以相同方式被检测到的结论。
