An invariant relation between changing over and reinforcement.
Switching between alternatives follows a fixed math rule tied straight to how reinforcers are handed out.
01Research in Context
What this study did
Kydd et al. (1982) tested pigeons on two keys that paid off at different rates.
The birds could hop between keys any time. Each hop was a "changeover."
The team also ran a computer model called "stat-bird" to mimic the birds.
They wanted one clean equation that linked changeovers to how reinforcers piled up.
What they found
The same simple rule fit both real pigeons and the stat-bird data.
When the left key paid twice as much, birds switched more often and stayed longer on that side.
The ratio of changeovers locked tightly to the ratio of reinforcers earned.
How this fits with other research
Rilling et al. (1969) showed pigeons match their TIME to payoff rates. R et al. added the switch itself as a measurable piece.
Kazdin (1977) proved the matching law works for rats choosing wheel running versus sugar water. R et al. tightened the math by folding in changeover moments.
Mellitz et al. (1983) looked at momentary maximizing — picking the key with the highest NEXT-reinforcer shot. Their data still follow the changeover rule R et al. found; the studies just focus on different slices of the same pie.
Why it matters
If you run concurrent schedules in your classroom, job site, or clinic, track how often the client switches between tasks. The switch rate tells you if the reinforcer rates are balanced. When you see too many hops, one side is probably paying more — adjust the schedules until the ratio of switches lines up with the ratio of rewards. This gives you a live dashboard for fairness and motivation.
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Join Free →Count changeovers during a two-choice task; if the ratio drifts from the reinforcer ratio, rebalance the payoffs.
02At a glance
03Original abstract
Although concurrent schedules may arrange reinforcers irregularly, relatively large numbers of reinforcers are obtained when an animal changes from one schedule to the other. This paper proposes a quantitative relation that predicts the proportion of reinforcers obtained when an animal is working on a schedule and the proportion when the animal changes over to a schedule. Basically the relation states that the number of reinforcers obtained while an animal works on a schedule varies directly with the relative amount of time spent working on that schedule; and the number of reinforcers obtained when an animal changes to a schedule varies directly with the relative amount of time spent on the alternate schedule. An important aspect of this relation is that when relative reinforcement rates are less than .50, more reinforcers are obtained just after an animal changes to a schedule than at all other times when this schedule is engaged. Data obtained both from a stat-bird and a live pigeon were in close agreement with the quantitative predictions. The relation between changing over and reinforcement held across several procedural changes that included changes in relative reinforcement rate, changes from independent to interdependent scheduling procedures, and changes in the variable-interval reinforcement distributions. The results are discussed in terms of the effects of the local distribution of reinforcement on responding. The local reinforcement distribution can affect local response rates and affects the resulting matching relation. This arrangement has implications for explanations of choice.
Journal of the experimental analysis of behavior, 1982 · doi:10.1901/jeab.1982.38-327