Discrimination of frequency variance for tonal sequences

作者：Byrne Andrew J^*; Viemeister Neal F; Stellmack Mark A

来源：Journal of the Acoustical Society of America, 2014, 136(6): 3172-3177.

DOI：10.1121/1.4900825

Real-world auditory stimuli are highly variable across occurrences and sources. The present study examined the sensitivity of human listeners to differences in global stimulus variability. In a two-interval, forced-choice task, variance discrimination was measured using sequences of five 100-ms tone pulses. The frequency of each pulse was sampled randomly from a distribution that was Gaussian in logarithmic frequency. In the non-signal interval, the sampled distribution had a variance of sigma(2)(STAN), while in the signal interval, the variance of the sequence was sigma(2)(SIG) (with sigma(2)(SIG) > sigma(2)(STAN)). The listener's task was to choose the interval with the larger variance. To constrain possible decision strategies, the mean frequency of the sampling distribution of each interval was randomly chosen for each presentation. Psychometric functions were measured for various values of sigma(2)(STAN). Although the performance was remarkably similar across listeners, overall performance was poorer than that of an ideal observer (IO) which perfectly compares interval variances. However, like the IO, Weber's Law behavior was observed, with a constant ratio of (sigma(2)(SIG)-sigma(2)(STAN)) to sigma(2)(STAN) yielding similar performance. A model which degraded the IO with a frequency-resolution noise and a computational noise provided a reasonable fit to the real data.

• 出版日期2014-12