Implications of research with nonspeech stimuli for speech processing: A summary of recent studies using world‐length tonal patterns

Abstract

A series of discrimination experiments with word‐length sequences of brief tones has demonstrated aspects of auditory processing not evident from studies with simpler stimuli (single tones, noise bursts, clicks). The primary new limitations on processing discovered with the nonspeech stimulus patterns are associated with (a) the level of stimulus uncertainty (size of the catalog sampled to generate a sequence of trials) and (b) the information content within the individual patterns (represented by the number of freely varying components per pattern). These jointly determine the level of informational masking within the patterns, a central limit on component detectability that can vary from 0 to 40–50 dB above the expected (peripherally determined) intercomponent temporal masking. These empirical results are interpreted in terms of three properties of auditory memory: long‐term memory (LTM), the accessibility of the properties of individual complex waveforms within the LTM, and the informational capacity o...