Perceptual classes established with forced-choice primary generalization tests and transfer of function.
In Experiment 1, 20 college students learned two identity conditional discriminations using squares that differed in interior-fill percentage (called Fill23 and Fill77). A two-choice generalization test was then presented with number of test trials varied across groups of subjects. The test samples were 19 squares that ranged in fill value from 23% to 77%; the comparisons were squares with Fill23 and Fill77. The resulting gradients did not vary as a function of number of test trials. When the generalization test was repeated with a third comparison, "neither," the ranges of fill values that occasioned the exclusive selection of Fill23 or Fill77 were direct functions of the number of prior two-choice generalization trials. Finally, a disriminability test revealed that Fill23 and Fill77 were disciminable from the intermediate fill values. In Experiment 2, perceptual classes were established with 5 new students using 760 forced-choice generalization test trials. The student were then trained to select a different glyph in the presence of Fill23 and Fill77, followed by a three-choice generalization test in which the 19 fill stimuli served as samples and the two glyphs served as comparisons. The gradients ovelapped with those previously obtained during the three-choice generalization test that used Fill23 and Fill77 as comparisons. Finally, a discriminability test showed that many adjacent stimuli along thc fill dimension were discriminable from each other. Together, the results of both experiments suggest that ranges of fill-based stimuli functioned as members of perceptual classes, and each class also functioned as a transfer network for a new selection-based response.
Reeve
K F
KF
Queens College andThe Graduate School and University Center of the City University of New York, Flushing 11367, USA. DrKFReeve@aol.com
Fields
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L
D000328:Adult; D002755:Choice Behavior; D003213:Conditioning, Psychological / Q000502:physiology; D004193:Discrimination Learning / Q000502:physiology*; D005793:Generalization, Psychological; D006801:Humans; D010465:Perception / Q000502:physiology*; D011897:Random Allocation; D013997:Time Factors