On the tolerance of spectral blur in the perception of spoken words.

Abstract

How does a listener resolve linguistic properties conveyed by speech? Many descriptions attribute a role to brief spectral details in narrow frequency ranges. Perceptual standards allow far more variety, revealed by the robustness of perception of distorted speech. The present study considered effects of spectral blur on the recognition of words. Listeners heard presentations of noise-vocoded Easy and Hard words. The number of spectral channels increased with each presentation, reducing blur within a trial. Test conditions varied the severity of initial blur, either 1 or 5 channels. In all conditions, the final presentation had 9 bands, yielding a net blur reduction of 4 or 8 bands. A control used two repetitions of each word at 9 spectral bands. Across the tests, exposure to spectral blur impaired the recognition of Easy and Hard words alike regardless of the listener's initial exposure. The pattern of results exposes the role of attention, uncertainty and spectral resolution in the phonetic contribution to word identification.