MacDonall, J. S. (2003).
Reinforcing staying and switching while using a changeover delay.
Journal of the Experimental Analysis of Behavior,
79, 219-232.
Performance on concurrent schedules can
be decomposed to run lengths (the number of responses before
switching alternatives), or visit durations (time at an
alternative before switching alternatives), that are a function
of the ratio of the rates of reinforcement for staying and
switching. From this analysis, a model of concurrent performance
was developed and examined in two experiments. The first exposed
rats to variable-interval schedules for staying and for
switching, which included a changeover delay for reinforcers
following a switch. With the changeover delay, run lengths and
visit durations were functions of the ratios of the rates of
reinforcement for staying and for switching, as found by previous
research not using a changeover delay. The second directly
assessed the effect of a changeover delay on run lengths and
visit durations. Each component of a multiple schedule consisted
of equivalent stay and switch schedules but only one component
included a changeover delay. Run lengths and visit durations were
longer when a changeover delay was used. Because visit duration
is the reciprocal of changeover rate, these results are
consistent with the established finding that a changeover delay
reduces the frequency of switching. Together these results
support the local model of concurrent performance as an
alternative to the generalized matching law as a model of
concurrent performance. The local model may be preferred when
accounting for more molecular aspects of concurrent performance.
Key words: concurrent schedules, changeover delay, generalized
matching law, local model, stay reinforcers, lever press, rats