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Behavioral Contrast In Pigeons And Rats: A Comparative Analysis, James Dougan, Frances Mcsweeney, Valeri Farmer-Dougan

James Dougan

The effects of reinforcement rate on behavioral contrast were examined in pigeons and rats. Each species was exposed to a series of 12 multiple variable-interval schedules, divided into four 3-schedule series. Each series consisted of a standard contrast manipulation, and baseline schedules provided a different rate of reinforcement in each of the series. The functions relating reinforcement rate to the magnitude of contrast were different across species. Rats showed a U-shaped function, with reliable contrast occurring only at high reinforcement rates. Pigeons showed an inverted U-shaped function, with contrast occurring on all schedules except the schedule providing the lowest rate …