EARLY LEVELS OF ANALYSIS OF SPEECH

A fundamental goal of an information-processing approach to speech per ception is to specify the levels of analysis between the initial senso ry coding of the signal and the recognition of the phonetic sequence t hat it conveys. A series of experiments provides evidence fur at least 3 qualitatively different levels of analysis involved in the percepti on of speech. Several properties for the representations of each level are described, including a locus (peripheral or monaurally driven vs. central or binaurally driven), a stimulus domain, and the mechanisms involved in response adjustment as a function of repeated stimulation. The stimulus domains for the 3 levels are (a) processes that deal wit h simple acoustic patterns, (b) processes that integrate more complex acoustic patterns, and (c) processes that represent categorical or pho netic information, The convergence among several different approaches used to determine levels of analysis supports the 3-level model.