Concurrent schedules: short- and long-term effects of reinforcers.
One reinforcer nudges the next response, while many reinforcers bend long-term preference.
01Research in Context
What this study did
Landon et al. (2002) worked with pigeons in a lab.
The birds pecked two keys. Each key paid off on its own timer.
The team changed how many reinforcers each side gave. They watched where the bird pecked right after grain and also over the whole session.
What they found
One reinforcer caused a quick jump in pecks to that key.
Over minutes the birds also drifted toward the key that paid more often.
The jump was biggest when one key paid far more than the other.
How this fits with other research
Landon et al. (2003) later used mixed payoffs instead of fixed ratios. They saw the same two time scales, proving the pattern holds when rewards come in streaks.
Friedling et al. (1979) warned that six sessions are needed to wash out old history. The 2002 paper zooms in and shows why: short-term carry-over lives inside each session.
Boutros et al. (2011) split the reinforcer into two jobs—signal and strengthener. Their split aligns with Jason’s finding: the signal acts right away, the strengthener builds slowly.
Why it matters
Your client’s choice has the same two layers. A single praise blip can swing the next response, but steady payoff shapes long-term preference.
When you shift reinforcement ratios, expect an early spike toward the richer option. Plan for at least six sessions before trust your data. Watch for big swings if the new ratio is extreme.
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Join Free →After you change the payoff rate in a concurrent choice probe, record the first five responses separately from the rest of the session to spot the immediate bump.
02At a glance
03Original abstract
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.
Journal of the experimental analysis of behavior, 2002 · doi:10.1901/jeab.2002.77-257