Department of Speech, Language, and Hearing Science, Purdue University, West Lafayette, Indiana 47907, USA.
J Acoust Soc Am. 2010 Dec;128(6):3597-13. doi: 10.1121/1.3500693.
The auditory system calibrates to reliable properties of a listening environment in ways that enhance sensitivity to less predictable (more informative) aspects of sounds. These reliable properties may be spectrally local (e.g., peaks) or global (e.g., gross tilt), but the time course over which the auditory system registers and calibrates to these properties is unknown. Understanding temporal properties of this perceptual calibration is essential for revealing underlying mechanisms that serve to increase sensitivity to changing and informative properties of sounds. Relative influence of the second formant (F(2)) and spectral tilt was measured for identification of /u/ and /i/ following precursor contexts that were harmonic complexes with frequency-modulated resonances. Precursors filtered to match F(2) or tilt of following vowels induced perceptual calibration (diminished influence) to F(2) and tilt, respectively. Calibration to F(2) was greatest for shorter duration precursors (250 ms), which implicates physiologic and/or perceptual mechanisms that are sensitive to onsets. In contrast, calibration to tilt was greatest for precursors with longer durations and higher repetition rates because greater opportunities to sample the spectrum result in more stable estimates of long-term global spectral properties. Possible mechanisms that promote sensitivity to change are discussed.
听觉系统以增强对声音中较不可预测（更具信息量）方面的敏感性的方式，对聆听环境的可靠属性进行校准。这些可靠的属性可能是频谱局部的（例如，峰）或全局的（例如，总体倾斜），但听觉系统记录和校准这些属性的时间过程尚不清楚。了解这种感知校准的时间特性对于揭示有助于提高对声音变化和信息性属性的敏感性的潜在机制至关重要。第二共振峰（F(2)）和频谱倾斜的相对影响是通过测量跟随前导上下文的/u/和/i/的识别来测量的，前导上下文是具有频率调制共振的谐波复合体。与后续元音的 F(2)或倾斜相匹配的滤波器过滤前导，分别引起对 F(2)和倾斜的感知校准（影响降低）。对于持续时间较短的前导（250 毫秒），校准到 F(2)的效果最佳，这表明存在对起始敏感的生理和/或感知机制。相比之下，对于具有较长持续时间和较高重复率的前导，校准到倾斜的效果最佳，因为有更多机会对频谱进行采样，从而对长期全局频谱属性的估计更加稳定。讨论了促进对变化敏感的可能机制。
