International Journal of Comparative Psychology

In order to test the effects of qualitatively varied reinforcement on response rates 3 experiments were conducted. The goal of the first experiment was asses the level of substitutability between two reinforcers   8 female Wistar rats kept on a diet consisting solely of turnip and millet seeds, subjects were exposed to a concurrent FR5 FR5 and then to a FR4 FR8 program, by the end of the experiment there was a swift in consumption, albeit to a small degree. During the second experiment, 8 female Wistar Rats were exposed to a three-component variable interval program which consisted of three components; one during which only millet seeds were available, one in which only turnip seeds were available and a third component in which both kinds of seeds were delivered randomly. By the end of the experiment the highest response rates were recorded during the component in which only millet seeds were available. Finally, a Third experiment was implemented in order to assess whether the particular way in which the substitutable consequences are delivered (i.e., random or simultaneously) has an effect on response rates. The program for this experiment consisted of a VI 60`s with two components. During one of the components a mixture of millet seeds was delivered when subjects responded after the interval was reached while during the second component either millet and turnip seeds were delivered randomly. By the end of the experiment no differences between components were found.  Results are discussed in terms of their implications for the study of reinforcement.