COGNITIVE SCIENCE 17m 143-147 (1993)

Comparing the Core and the Peel of the Same Fruit

MADELEINE LEMIEUX AND GEORGES BORDAGE

University of Illinois at Chicago

Patel and Groen's (1993) comments on our recent article bring out the fits and misfits of semiotics in relation to cognitive psychology. The debates within a discipline, and, more so, between disciplines should not create a growing misunderstanding among researchers, but rather enhance the formal comprehension of a precise object of inquiry: in this case, medical diagnos- tic thinking. Cognitive psychology and semiotics are allied fields; however, their respective epistemiological orientations produce different interpreta- tions of certain structural phenomena. The relationship and distinctions between the two disciplines need to be clarified further.

Cognitive psychology and semiotics are both interested in cognition and are confronted with the problem of elaborating a general theory and ade- quate methods that produce a coherent global explanation related to many areas of knowledge. The diversity of areas has led some researchers to select "domain-free" methods, such as in Patel and Groen (1986), whereas others, such as ourselves, have opted for a "specific genre" approach. In their comments, Patel and Groen do not discuss the critique raised by us (Lemieux & Bordage, 1992) concerning the shortcomings of the domain- free approach. This aspect of their methodology is at the very heart of the contribution of semiotics to cognitive psychology. In this comment we con- sider the selection of one method over the other, as well as the "surface" aspects of syntactic structures, that is, the propositional ordering of a text and the "deep" aspects of semantic structures, the abstract properties derived from a text (Ducrot & Todorov, 1979, pp. 108-II I).

Cognitive psychology and semiotics are different in that cognitive psy- chology is concerned with problems of learning and memorizing facts and information (e.g., clinical cues) whereas semiotics addresses problems of signification or meaning. Cognitive psychology addresses chiefy the mech- anisms by which the components of a knowledge domain are encoded in

Correspondence and requests for reprints should be sent to Georges Bordage, Department of Medical Education (M/C 591), College of Medicine, University of Illinois, 808 South Wood Street, Room 986 CME, Chicago, IL 60612-7309.

143

144 LEMIEUX AND BORDAGE

memory. These components constitute an encyclopedic repository, which is considered, possibly unconsciously, as syntactic units, that is, as an available lexical index. On the other hand, semiotics, more precisely, structural sem- antics, studies how the terms contained in a discursive syntax, a text, carries messages whose meaning is decoded according to a semantic classification system. We described in detail the semantic classification systems used in neurology and gastroenterology (Bordage & Lemieux, 1991; Lemieux & Bordage, 1986, 1992). The meaning of a text is compared and contrasted with the meaning of knowledge in memory according to a dialectic process of analogies and formal differences. This type of decoding of information underlines the importance of recognizing the referential value of a text in solving a clinical case. While acknowledging Patel and Groen's (1993) com- ments about what was meant by "without reference to the original text" (p. 137), we maintain that in their interpretation of the results, the impor- tance of the referential value of the text was not sufficiently emphasized. The decoding process itself becomes a type of memory organization or struc- tured knowledge. Thus, semiotics offers a new perspective to cognitive psy- chology as to what constitutes the semantics of a discourse as well as the dynamic decoding and encoding that underlie the formal comprehension of a text and its memorization.

Patel and Groen argue that semiotics is a framework as opposed to a theory. Semiotics is a well-established theory issued from modern linguistics as we clearly described (Lemieux & Bordage, 1992). Structuralism, an im- portant theoretical current in semiotics, has been applied to many human sciences including cognitive psychology (Piaget, for example). Propositional analysis also stems from modern linguistics, more precisely from generative grammar first developed by Chomsky (1965). Chomsky built an extensive theory and methodology to analyze syntactic structures (excluding, how- ever, the complementarity techniques of expert systems used by Patel and Groen, 1986). Chomsky's work was also the basis of the distinction between surface (or syntactic) and deep (or semantic) structures.

A theory is always based on a set of concepts and assumptions that pro- duce one or many constructs. Contrary to Patel and Groen's (1993) stance, structural semantics is a theory in its own right and not a "framework [with] a general pool of constructs.., not tightly enough organized to constitute a predictive theory" (p. 135). Structural semantics does, however, address different or broader variables, but that is not to say that it does not consti- tute a theory. Based on well-developed constructs in structural semantics and adhering to set canons of scientific inquiry (see Lemieux & Bordage, 1986), it was hypothesized that the more accurate diagnosticians would be those with the most diversified and elaborate set of semantics axes, and that subjects at various levels of experience (not to be confused with exper- tise) could exhibit different levels of structural expertise within and across

THE CORE AND THE PEEL 145

levels. The research data accumulated in two medical specialties, neurology (using four cases) and gastroenterology (using four cases), corroborated these hypotheses. Thus, structural semantics is not "a general pool of con- structs" but a well-organized theory based on the notion of binary opposi- tions, the semantic axes, and has predictive validity.

Syntactic studies of clinical reasoning (e.g., forward-backward reason- ing) have limited educational value because teaching someone to initiate his or her thinking either with the facts or diagnoses does not guarantee that a clinician will use the relevant facts or the pertinent hypotheses. The educa- tional value of structural semantics is more far-reaching than that of the forward-backward reasoning theory because it more fully describes the mental scaffolding that the "good" diagnostician uses when abstracting clinical signs and symptoms that lead to diagnoses. The novice not only aspires to forward reasoning but, with the insights provided by structural semantics, knows how to reason, how to organize globally his or her medical knowledge into abstract oppositions.

Patel and Groen (1986) also did not address specifically the "predictive" value of their theory as applied in their more recent work. In science, the results of a study can be predicted if the rules already stated in a theory are reproduced by experimentation with a high level of regularity. If these rules are constant, then a general law can be stated related to the determinism in the object studed (e.g., forward reasoning determines accurate performance). More recently, Patel, Groen, and Arocha (1990) studied "the factors that disrupt the pattern of forward reasoning characteristics of experts with accurate performance" (p. 394). In doing so they are in the ambiguous posi- tion of trying to discover the rules related to the exceptions to the rules described in their previous work. They conducted two experiments. The first experiment was identical to the one described by Patel and Groen (1986); the same case and task were used and required the subjects to name a diag- nosis. Patel, Groen, and Arocha (1990) arrived at the same interpretation as Patel and Groen (1986), that is, forward reasoning corresponds to accurate performance. In the second experiment, the case was said to be "ill-struc- tured" (p. 398) because it referred to a patient with a main and a secondary disorder. Patel, Groen, and Arocha concluded from the second experiment that "the breakdown of forward reasoning was related to the structure of the task. In particular, nonsalient cues induced some backward reasoning even in subjects with accurate diagnoses" (p. 394). This more nuanced inter- pretation addresses the adequacy of the tasks or protocols chosen in the study. Again, a scientific theory must take reality into account. It is, thus, essential to select cases and tasks that refer to reality. In the real clinical context, "well-structured" and "ill-structured" cases are both part of daily medical practice. The difference in performance come not from "ill- or well-structured clinical problems," as defined by Patel and Groen, but from

146 LEMIEUX AND BORDAGE

the very essence of diagnostic reasoning, which requires that alternative hy- potheses be confronted and that this requirement regularly produces a mix- ture of forward and backward reasoning; even for a patient with a single disorder, multiple hypotheses are entertained along the way.

Patel's previous work and that of colleagues, which showed the deter- minism of forward reasoning, were always related to naming a diagnosis and to the "immec~ate" presentation of a case, as opposed to a "sequen- tial" presentation (as used by us). In another recent study, Joseph and Patel (1990) used a sequential approach; in that study they did not give explana- tions in terms of forward-backward reasoning. "Sequential" presentations are more adequate in the study of diagnostic reasoning because they better reflect reality, that is, the clinical cues appear in successive segments, either expressed by the patient or produced by the clinician's questions, physical exam, or lab and radiological orders. We (Lemieux and Bordage, 1992) applied our structural methodology to Patel and Groen's (1986) "imme- diate" presentation approach and found the same results as in the sequen- tial situations used in our previous work (Bordage & Lemieux, 1991; Lemieux & Bordage, 1986), that is, the better diagnosticians use more varied semantic axes. The results are thus independent of the type of presentation used in the protocols and illustrate the high regularity of results found by applying structural semantic methods.

We did not limit our study to the problem of competence, but provided, with the tools of semiotics, a very extensive description of the structural components, mental operations, and specific patterns of diagnostic reason- ing (see Lemieux & Bordage, 1985). This highlights the importance in sem- iotics of studying first the specific genre of a cognitive domain before using domain-free approaches. This "specific" approach, along with the concep- tual and methodological tools of semiotics, brings to cognitive science a new paradigm that highlights the formal mechanisms of signification that are allied to the mechanisms of memorization and knowledge. We do not think that our approach is monolithic but rather complementary to other ap- proaches described in the cognitive literature (e.g., production rules). In reanalyzing Patel and Groen's 1985 protocols, we did not compare "apples and oranges" but rather the core and peel of the same fruit, the deep and surface structures of diagnostic reasoning.

REFERENCES

Bordage, G., & Lemieux, M, (1991). Semantic structures and diagnostic thinking of experts and novices. Academic Medicine, 66(9), $70-$72.

Chomsky, N. (1965). Aspects de la th~orie syntaxique. [Aspects of the syntactic theory]. Paris: Seuil.

Ducrot, O., & Todorov, T. (1979). Encyclopedia dictionary of the sciences of language (C. Porter, Trans.). Baltimore, Johns Hopkins University Press.

THE CORE AND THE PEEL 147

Joseph, G.-M., & Patel, V. (1990). Domain knowledge and hypothesis generation in diagnostic reasoning. Journal of Medical Decision Making, 10, 31--46.

Lemieux, M., & Bordage, G. (1986). Structuralisme et pddagogie mddicale: l~tude compara- tive des stratdgies cognitives d'apprentis-mddecins [Translated by Bordage: Structural- ism and medical education: A comparative study of the cognitive strategies of novice physicians]. Recherches S~miotiquies/Semiotic Inquiry, 6, 143-179.

Lemieux, M., & Bordage, G. (1992). Propositional versus structural semantic analyses of medical diagnostic thinking. Cognitive Science, 16, 185-204.

Patel, V.L., & Groen, G.J. (1986). Knowledge-based solution strategies in medical reasoning. Cognitive Science, 10, 91-116.

Patel, V.L., & Groen, G.J. (1993). Comparing apples and oranges: Some dangers in confusing frameworks with theories. Cognitive Science, 17, 135-141.

Patel, V., Groen, G., & Arocha, J. (1990). Medical expertise as a function of task difficulty. Memory & Cognition, •8(4), 394--406.