Mixed Fixed-Ratio Schedules II: The Effect of a Stimulus Change on Primes in the Large Ratio

Abstract

In mixed schedules which consist of large asid small fixed-ratio components, a pheno­menon known as priming occurs. Primñig is evident when a run of responses followed by a pause occurs at the beginning of the large fixed ratio. The length of this run approximated the number of responses iii the small ratio. The present study compared priming under a mixed fixed-ratio 10 fixed-ratio 100 schedule in which a change m key color was programmed in the large ratio with priming under the same núxed schedule without the stimulus change. In Experiment 1, príming developed much slower and the number of responses iii a prime was more variable in the mixed schedúle without the stimulus change than the mixed schedule with a stimulus change following the first ten responses in the large ratio. In Experiment II, two factors were examined: (1) the role played by the presence of the food-reinforced fixed-ratio 10 component and (2) the location of the stimulus change m the large fixed-ratio component. Priming occurred only when the food-reinforced fixed-ratio 10 component was present. The location of the stimulus change determined the distribution of the number of responses in a priming run which suggests that the control exerted by the stimulus change could be transferred to stimuli along the response dimension.