Landon, J., Davison, M., & Elliffe, D. (2002).
Concurrent schedules: Short- and long-term effects of reinforcers.
Journal of the Experimental Analysis of Behavior,
77, 257-271.
Five pigeons were trained on concurrent variable-interval
schedules in a switching-key procedure. The overall rate of
reinforcement was constant in all conditions, and the ratios of
reinforcers obtainable on the two alternatives were varied over
seven levels. Each condition remained in effect for 65 sessions,
and the last 50 sessions of data from each condition were
analyzed. The most recently obtained reinforcer had the largest
effect on current preference, but each of the eight previously
obtained reinforcers had a small measurable effect. These effects
were larger when the reinforcer ratio was more extreme. A longer
term effect of reinforcement was also evident, which changed as a
function of the reinforcer ratio arranged. More local analyses
showed regularities at a reinforcer-by-reinforcer level and large
transient movements in preference toward the just-reinforced
alternative immediately following reinforcers, followed by a
return to stable levels that were related to the reinforcer ratio
in effect. The present data suggest that the variables that
control choice have both short- and long-term effects and that
the short-term effects increased when the reinforcer ratios
arranged were more extreme.
Key words: concurrent schedules, choice, generalized matching,
reinforcement, key peck, pigeon