PSY 341 Lecture Notes - Lecture 21: Exemplar Theory, Dependent And Independent Variables, Predictive Validity
8 Dec 2016
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Posner and keele study of prototypes: asked whether we use prototypes in categorizing stimuli, study phase. See 10 exemplars of dot patterns from several training sets for 10 seconds each. Training sets formed by slightly distorting position of dots of prototypes that are never studied: test phase. Some unrelated fillers (new and not created from prototype: not similar to exemplars or prototype. Faster rts and higher confidence ratings for exemplars than fillers (expected result) Faster rts and higher confidence ratings for prototypes than exemplars! In later experiments, it was proven that the more exemplars deviated from the prototype, the longer it took to categorize them and the less confident people were. Results suggest that we develop centroids/averages/prototypes to efficiently represent category knowledge even when we have never encountered the prototype. Accounts for graded structure effects (e. g. birds, dot patterns) Variations in degree of similarity to prototype. Accounts for similarity judgments (cid:894)ro(cid:271)i(cid:374), sparro(cid:449), fla(cid:373)i(cid:374)go (cid:895)
