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Preshift Reward Magnitude and Positive Contrast in the Rat
Roger L. Mellgren, Jeffrey A. Seybert, Dan M. Wrather and Dennis G. Dyck
The American Journal of Psychology
Vol. 86, No. 2 (Jun., 1973), pp. 383-387
Published by: University of Illinois Press
Stable URL: http://www.jstor.org/stable/1421448
Page Count: 5
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Four groups of rats were given 24 trials of training in a straight runway with 1, 2, 4, or 8 food pellets, and then shifted to 8 pellets. There was a 20-sec delay of reinforcement on each trial, to prevent a ceiling effect on running speeds. The three shifted groups showed stable positive contrast relative to the unshifted control group. Postshift running speed was inversely related to magnitude of preshift reward.
The American Journal of Psychology © 1973 University of Illinois Press