JOURNAL OF MEMORY AND LANGUAGE 27, 143- 165 (1988) Cognitive Penetration of the Mechanisms of Perception: Compensation for Coarticulation of Lexically Restored Phonemes JEFFREYL.ELMAN University of Calij?kmia. San Diego AND JAMES L. MCCLELLAND Carnegie Mellon University An important question in language processing is whether higher-level processes are able to interact directly with lower-level processes, as assumed by interactive models such as the TRACE model of speech perception. This issue is addressed in the present study by exam- ining whether putative interlevel phenomena can trigger the operation of intraievei pro- cesses at lower levels. The intralevel process involved the perceptual compensation for the coarticulatory influences of one speech sound on another. TRACE predicts that this com- pensation can be triggered by illusory phonemes which are perceived as a result of top- down, lexical influences. In Experiment 1, we confirm this prediction. Experiments 2 to 4 replicate this finding and fail to support several potential alternative explanations of the results of Experiment i. The basic finding that intralevel phenomena can be triggered by interlevel processes argues against the view that aspects of speech perception are encapsu- lated in a module impervious to influences from higher levels. Instead, it supports a central premise of interactive models, in which basic aspects of perceptual processing are subject to influences from higher levels. 0 1988 Academic PRSX. Inc. How far down into the mechanisms of perception do higher-level contextual influ- ences reach? There has been considerable debate on this issue and the more general question of the degree to which cognitive processes interact with one another. Some theorists (e.g., Fodor, 1983) have proposed that processing is essentially modular in nature, and that the notable feature of cog- nition is the autonomy of mental faculties. This is the autonomous or modular view. Others have argued that the flow of infor- mation is rather freer, and that top-down as well as bottom-up interactions are pos- sible. This is the interactive view. The issue is a diffkult one to decide, because there is Requests for reprints should be addressed to Dr. Elman at the Department of Linguistics, University of California, San Diego, La Jolla, CA 92093. considerable overlap in the predictions made by the two accounts. Many of the phenomena which have been cited as evi- dence for either the autonomous or interac- tive theories are in fact compatible with both. In this paper we consider the question as it arises in the perception of speech. We describe a technique which we believe pro- vides a rigorous test of the existence of true top-down interactions in processing. The technique is applied here to the domain of speech perception, but we believe it can also be used in other areas where these issues arise. Using this technique, we find that higher-level contextual factors can trigger compensatory processes that are basic to speech perception. These findings demonstrate that a more direct effect of I43 0749-5%X/88 $3.00 Copyright 0 1988 by Academic Press. Inc. All rights of reproduction in any form reserved.