title: Identifying strategy use in category learning tasks: a case for more diagnostic data and models.
abstract: The strength of conclusions about the adoption of different categorization strategies-and their implications for theories about the cognitive and neural bases of category learning-depend heavily on the techniques for identifying strategy use. We examine performance in an often-used "information-integration" category structure and demonstrate that strategy identification is affected markedly by the range of models under consideration, the type of data collected, and model-selection techniques. We use a set of 27 potential models that represent alternative rule-based and information-integration categorization strategies. Our experimental paradigm includes the presentation of nonreinforced transfer stimuli that improve one's ability to discriminate among the predictions of alternative models. Our model-selection techniques incorporate uncertainty in the identification of individuals as either rule-based or information-integration strategy users. Based on this analysis we identify 48% of participants as unequivocally using an information-integration strategy. However, adopting the standard practice of using a restricted set of models, restricted data, and ignoring the degree of support for a particular strategy, we would typically conclude that 89% of participants used an information-integration strategy. We discuss the implications of potentially erroneous strategy identification for the security of conclusions about the categorization capabilities of various participant and patient groups.
authors.affiliation: School of Psychology, University of New South Wales.
authors.forename: Chris
authors.initials: C
authors.lastname: Donkin
authors.affiliation: School of Psychology, University of New South Wales.
authors.forename: Ben R
authors.initials: BR
authors.lastname: Newell
authors.affiliation: Department of Psychology, Syracuse University.
authors.forename: Mike
authors.initials: M
authors.lastname: Kalish
authors.affiliation: School of Psychology, University of Adelaide.
authors.forename: John C
authors.initials: JC
authors.lastname: Dunn
authors.affiliation: Department of Psychological & Brain Sciences, Indiana University.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Nosofsky
mesh_terms: D003210:Concept Formation; D004192:Discrimination, Psychological; D006801:Humans; D007858:Learning; D008960:Models, Psychological; D011336:Probability; D011581:Psychological Tests; D014163:Transfer, Psychology