Effects of discrete-trials reinforcement frequency and changes in reinforcement frequency on preceding and subsequent fixed-ratio performance

Presented 2 experiments which investigated effects of reinforcement frequency on preceding and subsequent discrete-trials lever pressing in 24 naive, male hooded rats. 2 distinctively cued 8-response ratios were separated by a 10-sec midtrial interval. Reinforcement frequency of the 1st ratio was varied over 0, 50, 100%. The 2nd ratio was always reinforced. It was found that response rates in the 1st ratio were unaffected by reinforcement frequency unless consistent nonreinforcement followed a history of reinforcement. 2nd-ratio responding was faster after nonreinforced 1st ratios, but this effect was not related to reinforcement history. While reinforcement-induced demotivation is adequate to explain 2nd-ratio performance, frustration theory is called upon in dealing with 1st-ratio effects. The need for demotivation controls in frustration research is emphasized and the usefulness of nonreinforced control procedures is questioned. The role of 2nd-ratio reinforcement in maintaining 1st-ratio responding is discussed. (27 ref.)