COGNITIVE PSYCHOLOGY 22, 493-516 (1990) A Critical Reappraisal of the Evidence for Unconscious Abstraction of Deterministic Rules in Complex Experimental Situations PIERRE PERRUCHET,* JORGE GALLEGO,~ANDISABELLE SAVY *UniversittS Rem&Descartes and f Universite’ Pierre et Marie Curie In a recent experiment (Lewicki et al., 1988) subjects were submitted to a four-choice RT paradigm for 3600 trials. On each of the successive logical blocks of five trials, the first two locations of the target were randomly distributed, and the last three locations were determined by complex rules. Although subjects were unable to verbalize the actual nature of the manipulation, performance on the last trials of each block improved at a faster rate and was better overall than performance on the first trials. In addition, subsequent rules changes on 480 additional trials only affected performance on the last three trials of each block. The present paper demonstrates that contrary to Lewicki et al’s assertions this performance pattern requires neither acquisition of tacit knowledge of the com- position rules, nor partitioning by the subjects of the sequence into logical blocks of five trials. Rather, the results can be accounted for by the relative frequency of a few simple sequences of target locations. Moreover, this alternative explanation alone correctly anticipates some striking features of tine-grained performance (Lewicki et al., 1988). The discussion focuses on methodological implications of these findings for investigation of unconscious learning, and speculates on what and how people learn when they encounter a complex and structured situ- ation. 0 1990 Academic Press, Inc. The recent literature reflects a growing interest in the distinction be- tween two modes of learning (e.g., Berry & Broadbent, 1988; Hayes & Broadbent, 1988; Mathews, Buss, Chinn, & Stanley, 1988; Perruchet, 1988; Reber, 1989). Although authors differ in their use of terminology and minor features of theoretical assessment, most would adhere to the following general description. The first mode of learning is thought to be activated when the situation to be learned is a simple one. People perform controlled operations on the conscious representation of identified and isolated variables of the stimulus environment. Traditional concept learn- ing and problem solving experiments deal primarily with this adaptive The study was supported by the CNRS, Universite Rem? Descartes, EPHE (3” section), and CNAM (Service de recherches de I’INOP). We would like to thank Pawel Lewicki for providing experimental material and detailed responses to our queries at the time this study was being planned, and for his helpful criticisms on an earlier draft of the present manu- script. We also appreciate the thoughtful comments of D. Kahneman and S. Palmer. Cor- respondence should be addressed to Pierre Perruchet, Laboratoire de Psychologie Differ- entielle, 28, rue Serpente, 75006, Paris, France. 493 OOlO-0285/90 $7.50 Copyright 0 1990 by Academic Press, Inc. All rights of reproduction in any form reserved.