Shahan, T. A., & Lattal, K. A. (2000).
Choice, changing over, and reinforcement delays.
Journal of the Experimental Analysis of Behavior,
74, 311-330.
In three experiments, pigeons were used to examine the
independent effects of two normally confounded delays to
reinforcement associated with changing between concurrently
available variable-interval schedules of reinforcement. In
Experiments 1 and 2, combinations of changeover-delay durations
and fixed-interval travel requirements were arranged in a
changeover-key procedure. The delay from a changeover-produced
stimulus change to a reinforcer was varied while the delay
between the last response on one alternative and a reinforcer on
the other (the total obtained delay) was held constant.
Changeover rates decreased as a negative power function of the
total obtained delay. The delay between a changeover-produced
stimulus change had a small and inconsistent effect on changeover
rates. In Experiment 3, changeover delays and fixed-interval
travel requirements were arranged independently. Changeover rates
decreased as a negative power function of the total obtained
delay despite variations in the delay from a change in stimulus
conditions to a reinforcer. Periods of high-rate responding
following a changeover, however, were higher near the end of the
delay from a change in stimulus conditions to a reinforcer. The
results of these experiments suggest that the effects of
changeover delays and travel requirements primarily result from
changes in the delay between a response at one alternative and a
reinforcer at the other, but the pattern of responding
immediately after a changeover depends on the delay from a
changeover-produced change in stimulus conditions to a
reinforcer.
Key words: choice, concurrent schedules, changeover delay,
travel, reinforcement delay, key peck, pigeons