Evolution of conceptual structure

Investigated a geometric model for the evolution of conceptual structure and prototype abstraction. Multidimensional scaling was used to assess the transformation of a conceptual space containing multiple categories from a relatively undifferentiated state to one that reflected the requisite category learning. Three experiments, each using 20 undergraduates, included a common rating phase involving 21 stimuli (prototype plus 6 exemplars from each of 3 categories), with the 3 experiments distinguished by prior manipulations of the amount of abstraction afforded the 3 categories. Across the 3 experiments, the degree of category structure for the entire conceptual space was enhanced, and the change in category structure was greatest for those categories defined by numerous patterns during learning. In addition, the prototype occupied an ideal location in each category in that the ratio of within- to between-categories distance was smallest for the prototype. It is suggested that the utility of using multidimensional scaling as an adjunct to category abstraction is that the changing structure of an entire conceptual space may be tracked, as variables underlying category abstraction are systematically manipulated. (22 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).