Uncertainty concerning the direct use of time information in hearing: Place clues in white-spectra stimuli

Abstract

Data on time response in the nervous system are available for animals. Rate‐matching data for humam subjects with implanted electrodes are available. These data do not tell us with certainty up to what rate people with normal hearing utilize time information directly. In many experiments an attempt to measure time response is confused by the presence of spectral clues. Short‐term spectral clues exist in stochastic sequences of positive and negative pulses and in modulated white noise, both of which have a white long‐term spectrum. These clues are periodicity (with a period equal to the pulse or modulation rate) and symmetry (about frequencies equal to integer multiples of half this rate), differences at different frequencies in the peak‐ or rms‐voltage distribution function of the output of a narrow‐band filter and, in the case of stochastic pulse sequences, differences in extreme intensity at different frequencies. It may be that the ability to match at high rates and the perception of tonal quality that subjects with excellent and trained hearing, such as musicians, exhibit for white‐spectrum stochastic pulse sequences or gated noise is due to the residue phenomenon or to spectral clues discussed in this paper.