Keypecking by 4 pigeons was studied on mixed schedules of reinforcement. Positive behavioral contrast was found when the schedule was shifted from Mixed VI VI to Mixed VI Extinction only when the VI schedule value was small relative to the component duration.
References
1.
AmselA. (1971) Positive induction, behavioral contrast, and generalization of inhibition in discrimination learning. In KendlerH. H. & SpenceJ. T. (Eds.), Essays in neobehaviorism.New York: Appleton-Century-Crofts. Pp. 217–236.
