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38 results on '"Ennis, John M."'

4. A Neurobiological Theory of Automaticity in Perceptual Categorization

Author

Ashby, F. Gregory, Ennis, John M., and Spiering, Brian J.

Abstract

A biologically detailed computational model is described of how categorization judgments become automatic in tasks that depend on procedural learning. The model assumes 2 neural pathways from sensory association cortex to the premotor area that mediates response selection. A longer and slower path projects to the premotor area via the striatum, globus pallidus, and thalamus. A faster, purely cortical path projects directly to the premotor area. The model assumes that the subcortical path has greater neural plasticity because of a dopamine-mediated learning signal from the substantia nigra. In contrast, the cortical-cortical path learns more slowly via (dopamine independent) Hebbian learning. Because of its greater plasticity, early performance is dominated by the subcortical path, but the development of automaticity is characterized by a transfer of control to the faster cortical-cortical projection. The model, called SPEED (Subcortical Pathways Enable Expertise Development), includes differential equations that describe activation in the relevant brain areas and difference equations that describe the 2- and 3-factor learning. A variety of simulations are described, showing that the model accounts for some classic single-cell recording and behavioral results.

Published
2007

38. Investigating the single ideal assumption using Ideal Profile Method

Author

Worch, Thierry and Ennis, John M.

Subjects
*HEDONISTIC consumption, *MULTIVARIATE analysis, *CONSUMERS, *COMMERCIAL product testing, *CHOCOLATE, *METHODOLOGY, *FOOD industry, *COOKING
Abstract

Abstract: Ideal point modeling is a type of multivariate mapping in which consumers are assumed to use internal ideals in their hedonic evaluation of products. In their calculation processes, these techniques typically assume that consumers have a unique ideal for the product set tested. But this assumption is difficult to verify from the liking data alone, and may be violated if different subcategories of products, such as light and dark chocolate, are included in the same experiment. In this paper we propose the use of the Ideal Profile Method (IPM) to test this assumption. In IPM, consumers are asked to rate explicitly their ideals for each product tested. The variability between products of the averaged ideal ratings can then be used to check for the assumption of a single ideal. The procedure we describe involves ANOVA and confidence ellipses associated to the Hotelling T 2 test. We then consider three cases to illustrate the use of this methodology in practice. [Copyright &y& Elsevier]

Published
2013
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