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LOCAL CONTRAST AND MAINTAINED GENERALIZATION
Author(s) -
Hinson John M.,
Malone John C.
Publication year - 1980
Publication title -
journal of the experimental analysis of behavior
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.75
H-Index - 61
eISSN - 1938-3711
pISSN - 0022-5002
DOI - 10.1901/jeab.1980.34-263
Subject(s) - peck (imperial) , contrast (vision) , psychology , reinforcement , stimulus (psychology) , generalization , contrast effect , pecking order , communication , mathematics , artificial intelligence , geometry , social psychology , cognitive psychology , mathematical analysis , computer science , biology , evolutionary biology
Pigeons received variable‐interval reinforcement for key pecking during presentations of horizontal and vertical line‐orientation stimuli, while pecks during five intermediate orientations were extinguished. Lowest peck rates were observed during presentations of negative stimuli adjacent to the positive orientations while peck rate during 45 degrees (the intermediate negative orientation) was relatively high, i.e., there were negative contrast shoulders. When peck rates were manipulated in the positive orientations, peck rate in neighboring orientations changed in the opposite direction. Contrast shoulders faded after prolonged training. A second type of contrast, local contrast, was correlated with similarity of preceding stimulus and different average peck rates during different stages of the discrimination process. The data suggest that sequential local contrast accompanying the formation of a discrimination contributes to the form of generalization gradients. Blough's model of stimulus control predicts the changes in gradient form described here, but may not accurately depict the underlying processes responsible for gradient form.