Synthesizing concurrent interval performances.
Concurrent interval schedules can be treated as two independent stay/switch pairs whose combined data still fit the matching law.
01Research in Context
What this study did
The team ran concurrent interval schedules. Two choices were on at the same time.
They treated each choice as a stay/switch pair. Then they merged the data.
They asked: does the combined data still fit the matching law?
What they found
Yes. The merged data still followed the matching law.
The animals picked the richer schedule in the same ratio as the payoffs.
How this fits with other research
Duker et al. (1996) got the same result with kids doing math problems. Both studies show the matching law holds under concurrent VI schedules.
McKearney (1970) and Dews (1966) proved that basic schedule patterns stay stable. The 2000 paper builds on that by showing the patterns also stay stable when you merge two interval schedules.
Rojahn et al. (1994) used money and cigarettes. They found the two reinforcers acted like separate schedules. The 2000 paper echoes this: you can treat each side of a concurrent schedule as its own unit.
Why it matters
You can now treat concurrent interval data as simple stay/switch pairs. This saves time. You do not need fancy math. Just pool the pairs and check the matching slope. Next time you run a choice session, try merging the data this way.
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Join Free →After your next concurrent VI session, split each choice into stay vs switch, pool the data, and plot the matching law to see if it still fits
02At a glance
03Original abstract
Concurrent schedules may be viewed as consisting of two pairs of stay and switch schedules, each pair associated with one of the alternatives. A stay schedule arranges reinforcers for staying and responding at one alternative, whereas the associated switch schedule arranges reinforcers for switching to the other alternative. In standard concurrent schedules, the stay schedule at each alternative is equivalent to the switch schedule at the other alternative. MacDonall (1999) exposed rats to one pair of stay and switch variable-ratio schedules and varied the response requirements across conditions. Combining results from symmetric pairs produced composite performances that were described by the generalized matching law. This outcome was noteworthy because the data were obtained from performances at two alternatives with contingencies that were functionally unrelated to each other. This result suggests that concurrent performances may consist of two unrelated performances that alternate as behavior moves between alternatives. The purpose of the present experiment was to extend those results to interval schedules. Rats were exposed to pairs of random-interval schedules, and across conditions their mean intervals were varied. When data from appropriately paired conditions were combined, the composite performances were consistent with the generalized matching law. In addition, the results supported two models of concurrent performances that were based on local variables at an alternative (behavior, and stay and switch reinforcers): a modified version of the contingency discrimination model (Davison & Jenkins, 1985) and the local model (MacDonall, 1999).
Journal of the experimental analysis of behavior, 2000 · doi:10.1901/jeab.2000.74-189