Department of Psychology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
J Acoust Soc Am. 2011 Feb;129(2):593-6. doi: 10.1121/1.3531838.
Highly detectable, time-reversed triangular amplitude modulation, with linear increases and decreases in amplitude, was used in an adaptive task to measure just-noticeable differences for changes in the direction of envelope temporal asymmetry for different modulation depths (m = 1.0 and 0.5) and rates (8, 16, and 32 Hz). Thresholds were analyzed using three different measures of the modulator's shape based on (1) the change in the position of the peak within a cycle, (2) the change in the slope of the modulator's increasing amplitude portion, and (3) the change in slope measured in units of amplitude per unit cycle rather than amplitude per unit time. The amplitude per unit cycle measure resulted in the best fit to all the data, and predicted additional data that were gathered with roved modulation frequency. The results suggest that a time normalization process may be involved in the perception and discrimination of envelope shape.
采用高可检测性、时间反转三角幅度调制，其幅度呈线性增加和减少，在自适应任务中用于测量不同调制深度（m=1.0 和 0.5）和速率（8、16 和 32 Hz）下包络时间不对称性变化的可察觉差异。使用基于调制器形状的三种不同度量来分析阈值：（1）在一个周期内峰值位置的变化，（2）调制器增大幅度部分斜率的变化，以及（3）以单位周期内的幅度变化而不是单位时间内的幅度变化来测量斜率。幅度单位周期的度量最符合所有数据，并且预测了用漫游调制频率收集的额外数据。结果表明，时间归一化过程可能涉及到对包络形状的感知和辨别。
