Non-linear Multiple Cue Judgment tasks

Non-linear Multiple-Cue Judgment Tasks Anna-Carin Olsson (anna-carin.olsson@psy.umu.se) Department of Psychology, Umea University SE-091 87, Umea, Sweden Tommy Enqvist (tommy.enqvist@psyk.uu.se) Department of Psychology, Uppsala University Box 1225, 751 42 Uppsala, Sweden Peter Juslin (peter.juslin@psyk.uu.se) Department of Psychology, Uppsala University Box 1225, 751 42 Uppsala, Sweden Cognitive models and processes Abstract In general, multiple cue judgments are well captured by multiple linear regression models (Brehmer, 1994, Cooksey, 1996). These regression models are statistical descriptions rather than process models, but implicitly this research is often committed to the idea that people use controlled proc- esses in working memory to mentally integrate cues accord- ing to a linear additive rule. In contrast, exemplar models assume that people make judgments by retrieving similar stored exemplars from memory (Medin & Schaffer, 1978; Nosofsky & Johansen, 2000). The exemplar representations in memory are the holistic concrete experienced instances often emphasized in categorization. The generalized judgment model Σ implicates a sequential adjustment process, compatible both with a linear, additive cue-integration rule, and the additive combination of exem- plars in exemplar models (Juslin et al., 2004), capturing the additive character of a judgment. By considering the struc- tural properties of a task environment, we are able to predict representational shifts in the process that support multiple cue judgment. In additive environments cue abstraction dominate, while exemplar memory dominates in multiplica- tive environments (Juslin et al., 2004). In the Σ model the previous estimate is adjusted every time a new piece of evidence is presented. If no new evidence is presented cues correspond to an a priori estimate. In Σ, cue abstraction involves sequential adjustment based on single cues, where the cue weight is relative to the cues presented so far. In contrast, the weight assigned to an exemplar is given by its similarity relative to the similarity to all exemplars retrieved so far. Because of the integration of stored criterion values instead of cue-criterion relations, Σ is not confined to any particular task structure. Therefore, the model can repre- sent any task structure as long as similar exemplars have similar criteria, which allows judgments also in non-linear and multiplicative environments (Juslin et al., 2004). In two experiments we examined which cognitive proc- esses people use in a non-linear multiple cue judgment task, proposing that people are not able to use explicit cue ab- straction when judging objects with a non-linear structure between the cues of the objects and the criterion and there- fore they are forced to use exemplar-based processes. Con- sistent with the results reveal strong exemplar effects in the non-linear condition. Introduction How do we judge if there seems to be no underlying structure or pattern in the things or events we have to judge? What knowledge representations do we use in these situations? Our ability to categorize the environment is important to us and different environmental categorization situations involve different processes, either in the form of analytic or intuitive thought. Multiple cue judgment tasks typically involve a probe defined by a number of binary or continuous cues and require a continuous judgment. Previous research suggests that by manipulating the task environment we can induce a shift between distinct cognitive processes (Juslin, Olsson, & Olsson, 2003). Two cognitive models of general concern in cognitive science, are the explicit, rule-based and analytic knowledge versus implicit, silent knowledge based on per- sonal experience (Hahn & Chater, 1998; Hammond, 1996; Sloman, 1996; E. E. Smith, Patalano, & Jonides, 1998). Re- search on multiple cue judgment has primarily stressed con- trolled integration of cues that have been abstracted in train- ing (Einhorn, Kleinmuntz, & Kleinmuntz, 1979) while ex- emplar models are emphasized by research on categorization (Nosofsky & Johansen, 2000; Nosofsky & Palmeri, 1997). In this article we address the following question: what structure of a categorization task triggers analytic thinking and what structure triggers intuition? We hypothesize that participants are not able to use cue abstraction in a non-linear task, be- cause the mind is constrained to linear additive integration of abstracted cue-criterion relations (Juslin, Karlsson, & Olsson, Judgment task and Model Predictions The participants used four binary cues to infer a continuous criterion in either a linear or a non-linear multiple-cue judg- ment task. The exotic (but fictitious) Death bug is the cover story in the task that involves judgments of the toxicity of