LOCAL RESPONSE‐RATE CONSTANCY ON CONCURRENT VARIABLE‐INTERVAL SCHEDULES OF REINFORCEMENT

Abstract

Concurrent variable‐interval schedules were arranged with a main key that alternated in color and schedule assignment, along with a changeover key on which a small fixed ratio was required to changeover. Acceptable matching was observed with pigeons in two replications, but there was a tendency toward overmatching. Local response rates were found to differ for unequal schedules of a concurrent pair: local response rate was greater for the variable‐interval schedule with the smaller average interreinforcement interval, but qualifications based on an interresponse‐time analysis were discussed. In a second experiment, two 3‐minute variable‐interval schedules were arranged concurrently, and the experimental variable was the changeover procedure: either a changeover delay was incurred by each changeover or a small fixed ratio on a changeover key was required to complete a changeover. Changeover delays of 2 and 5 seconds were compared with a fixed‐ratio changeover of five responses. The response output on the main key (associated with the variable‐interval schedules) was greater when a changeover delay was arranged than when a fixed ratio was required to changeover. A detailed analysis of stripchart records showed that a 2‐second delay generated an increased response rate for 3 seconds after a changeover, while the fixed‐ratio requirement generated an increased rate during the first second only, followed by a depressed response rate for 2 seconds.