A Probabilistic Feature Model for Unfolding Tested for Perfect and Imperfect Nestings

Complex stimuli can be represented as sets of features. Coombs' unfolding theory for preferential choice and for comparative similarity judgement is modeled for a feature representation of stimuli. This is called the Additive Random Feature model for Unfolding (ARFU). A special case is obtained if Restle's dissimilarity model applies, which we call ARFU-R. Its implications were tested for verbal and pictorial stimuli which exhibit a nesting or an imperfect nesting of their features. Nearly all of ARFU-R's predictions were satisfied at a 10% level of significance, which establishes the validity of ARFU-R for the stimuli used in a triadic comparisons task. The most salient results were (a) the low level of transitivity of subjects' choices, and (b) the subjects' failure to choose the standard when it was among the alternatives presented to the subject. Because of the nature of the task and the stimuli, these results would appear to apply also to two "real-life" tasks: Diagnosis of a mental illness syndrome and construction of an identikit picture of an offender. Copyright 1997 Academic Press. Copyright 1997 Academic Press