Demany L, Clément S
Laboratoire de Psychoacoustique, Université Bordeaux 2, France.
J Acoust Soc Am. 1995 Apr;97(4):2454-9. doi: 10.1121/1.411966.
In widely frequency modulated sine tones, frequency maxima are perceived more accurately than frequency minima: A shift in a local frequency extremum is better detected when the extremum is a maximum than when it is a minimum, even within the same spectral region [L. Demany and K. I. McAnally, J. Acoust. Soc. Am. 96, 706-715 (1994)]. It is reported here that this perceptual asymmetry is about equally strong for frequency extrema near 250 and 1000 Hz, but weaker near 4000 Hz. It was also found that near 1000 Hz, the asymmetry is about equally strong for stimuli with an SPL of 35 and 70 dB, although the neural excitation patterns of a 1000-Hz tone probably have a different shape--and more specifically a different asymmetry--at these two levels. Finally, stimulus uncertainty was found to reduce the perceptual asymmetry: A weaker asymmetry was measured when the standard frequency extremum varied randomly from trial to trial than when it was fixed. The latter result, and the fact that the asymmetry did not decrease with training in the discrimination task, suggest that the asymmetry cannot be counteracted by "top-down" attentional processes and may be a preattentional phenomenon.
在宽频调制正弦音调中，频率最大值比频率最小值能被更精确地感知：当局部频率极值是最大值时，比它是最小值时，局部频率极值的偏移能被更好地检测到，即使在相同频谱区域内也是如此[L. 德马尼和K. I. 麦卡纳利，《美国声学学会杂志》96，706 - 715(1994)]。据报道，这种感知不对称对于250赫兹和1000赫兹附近的频率极值来说强度大致相同，但在4000赫兹附近则较弱。还发现，在1000赫兹附近，对于声压级为35分贝和70分贝的刺激，这种不对称强度大致相同，尽管1000赫兹音调在这两个声压级下的神经兴奋模式可能具有不同的形状——更具体地说，是不同的不对称性。最后，发现刺激的不确定性会降低感知不对称：当标准频率极值在各次试验中随机变化时，所测量到的不对称性比其固定时要弱。后一个结果，以及在辨别任务中不对称性不会随着训练而降低这一事实，表明这种不对称性不能被“自上而下”的注意力过程抵消，可能是一种前注意现象。
