Stimulus functions in some chained fixed-ratio schedules of reinforcement.

For two pigeons, behavior was compared in equivalent two-link chained and tandem schedules in which 100 responses were required for food reinforcement but the responses required in the two links of the chained schedule were varied over the values 2-98, 50-50, and 98-2. Initial pausing, response rate in each link, and the total time to complete each ratio were recorded. In chained components, initial-link pausing (for both birds) and total time to complete the ratio (for one bird) were generally shorter when the response requirement was 2-98 than when it was 50-50 or 98-2; for terminal-link pausing this relationship was reversed for both birds. There were also systematic changes in behavior in tandem components, and in the relationship between behavior in chained and tandem components. The results are discussed in terms of conditioned reinforcement.