Coordination of analytic and similarity-based processing strategies and expertise in dermatological diagnosis

Background: Medical diagnosis may be thought of as a categorization task. R esearch and theory?, in psychology as well as medical decision making indic ate at least 2 processes by which this categorization task may be accomplis hed: (a) analytic processing, in which one makes explicit use of clinical f eatures to reach a diagnosis, and (b) similarity-based processing, in which one makes use of past exemplars to reach a clinical diagnosis. Recent rese arch indicates that these 2 processes are complementary Purpose: We investigate the coordination of analytic and similarity-based p rocesses in clinical decision making to examine if the relative reliance on these 2 processes is (a) amenable to instruction and (b) dependent on leve l of clinical experience. Methods: The reliance of these 2 processes was indexed by the performance o f 12 preclinical medical students on cases dichotomized as typical and atyp ical (analytic processing) and on cases dichotomized as similar or dissimil ar to cases seen previously in a training phase (similarity-based processin g;). Results: The results indicated that both processes are operative. Of partic ular interest was that preclinical medical students enhanced their performa nce by adopting a similarity-based strategy. This was especially so for aty pical cases. These results are in contrast to residents, who enhanced their performance by adopting an analytic strategy Conclusions: The relative reliance on analytic and similarity-based process es is amenable to instruction and dependent on expertise. Copyright (C) 200 1 by Lawrence Erlbaum Associates, Inc.