Abstract
Pigeons responded on multiple variable-interval variable-interval schedules of reinforcement in an open and a closed economy. Equal duration components were increased in duration while the component rates of reinforcement were held constant, the component schedules were reversed, and component duration was decreased. In the open economy, daily sessions were limited to 1 hr, and subjects were maintained at 80% of their free-feeding weights through supplemental feeding when necessary in their home cages. In the closed economy, subjects were housed in their experimental chambers and no deprivation regimen was enforced. Relative response rate decreased as components were lengthened in the open economy, whereas in the closed economy relative rate increased as components were lengthened. Response proportions overmatched reinforcer proportions to a greater extent at long component durations in the closed economy, but there was no systematic effect of component duration on responding in the open economy.