The theory-based model of categorization posits that concepts are represented as theories rather than as feature lists. Thus, it is particularly interesting that the DSM-IV (American Psychiatric Association, 1994), establishes a set of atheoretical guidelines for diagnosis in the domain of mental disorders. Five experiments investigated how clinicians handle an atheoretical nosology. Clinical psychologists' causal theories for DSM-IV disorders and their responses on diagnostic and memory tasks were measured. Participants were more likely to diagnose a hypothetical patient with a disorder if that patient had causally central rather than causally peripheral symptoms according to their theory of the disorder. They also showed biased memory for the causally central symptoms. Clinicians are cognitively driven to form and apply theories despite decades of training and practice with the DSM's atheoretical guidelines. Clinical Psychologists' Theory-Based Representations of Mental Disorders Predict their Diagnostic Reasoning and Memory The theory-based view of categorization proposes that concepts are represented as theories or causal explanations. Murphy and Medin (1985) suggested that our nave theories about the world hold the features of a concept together in a cohesive package. For instance, a layperson's concept of anorexia not only contains the features "fear of becoming fat" and "refuses to maintain minimal body weight," but also the notion that the fear of becoming fat helps cause the refusal to maintain minimal body weight (Kim & Ahn, 2002). Indeed, a growing body of evidence supports the notion that the human mind constantly seeks out rules and explanations that make sense of incoming data concerning its surroundings, and forms concepts based on its theories about the ...

this article unless noted otherwise). The names of ss'mptoms are abbreviated because of space limitations (full names of the criterial symptoms can be fbund in Table 1). The symptoms circled with double lines are criterial symptoms, and those circled with single lines are characteristic symptoms. One interesting result to notice is that even among criterial symptoms, causal centrality (as grossly indicated by the number of symptoms that a symptom causes and their strengths) seems highly variable. For instance, on average, participants believe that in anorexia nervosa, "fear of being fat even when underweight" causes many symptoms, including fear of eating in public, bingeing and purging, excessive dieting, and refusal to gain weight. However, "absence of the period (in women) for 3+ menstrual cycles," another criterial symptom for anorexia nervosa, was rarely judged to cause any other symptoms of that disorder. Figure 1 suggests that a conceptually central symptom (e.g., "fear of being fat even when underweight" in anorexia nervosa) is also causally central, and a conceptually peripheral symptom (e.g., "absence of the period (in women) tbr 3+ menstrual cycles") is also cansally peripheral. This would be consistent with our primary hypothesis that a symptom is conceptually central to the extent that it causes other features. However, it is also apparent from Figure 1 that not all such pairwise comparisons, as in all of psychological research, were perfect one-to-one correspondences. Therefore, we tested for statistical significance as follows

The ability to categorize and use concepts e#ectively is a basic requirementofany intelligent actor. The utility-based approach to categorization is founded on the thesis that categorization is fundamentally in service of action, i.e., the choice of concepts made by an actor is critical to its choice of appropriate actions. This is in contrast to classical and similarity-based approaches which seek logical completeness in concept description with respect to sensory data rather than action-oriented e#ectiveness. Utility-based categorization is normative and not descriptive. It prescribes howanintelligent agent ought to conceptualize to act e#ectively. It provides ideals for categorization, speci#es criteria for the design of e#ective computational agents, and provides a model of ideal competence. A decision-theoretic framework for utilitybased categorization whichinvolves reasoning about alternative categorization models of varying levels of abstraction is proposed. Categorization mode...

Fundamental to the science and practice of clinical psychology is a valid diagnostic nomenclature. Clinicians and researchers need a common language with which to describe what they are treating and studying. However, the diagnosis and classification of psychopathology has been and continues to be difficult and controversial. This chapter begins with an overview of the nature of diagnosis and classification. The history of the diagnosis of psychopathology is then briefly described, including the recent editions of the American Psychiatric Association’s (APA) diagnostic manual. Emphasis is given to issues of reliability, diagnostic stability, utility, cultural biases, and validity. Major controversies of the current diagnostic nomenclature are then discussed, including comorbidity, bias, the categorical-dimensional debate, and definitions of mental disorder. The chapter concludes

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