Temporal constraint on choice: Sensitivity and bias in multiple schedules.
Extra reinforcers in other components bias choice in predictable ways—count them or your data drift.
01Research in Context
What this study did
McLean et al. (1983) worked with pigeons on multiple schedules. They gave grain in one key color, then switched colors. Sometimes extra grain came from outside the main schedule.
The team tracked how these extra reinforcers changed each bird's key pecks and time spent. They wanted numbers that showed both sensitivity and bias.
What they found
Extra reinforcers from other components shifted both sensitivity and bias. More outside grain made the birds act as if the lean key paid better than it really did.
The shifts were steady and could be plotted. The paper gives formulas to correct for the hidden pay.
How this fits with other research
Rutter et al. (1987) ran almost the same birds and found the same pattern. They added response-based switches and still saw reinforcer rate rule the roost. This backs up the 1983 math.
Carr et al. (1985) seems to disagree. They tested short versus long components and found no sensitivity jump. The gap is simple: G held extra grain steady, while P let it vary. When extraneous pay is fixed, duration alone does little.
Beeby et al. (2017) stretched the idea to three and four keys. Richer keys still grabbed the first peck, showing the bias term travels beyond two choices.
Why it matters
If you run multiple schedules in practice, watch for hidden reinforcers. Praise from a side teacher, tokens from earlier work, or even a vending machine down the hall can tilt your data. Track these extras and plug them into the bias formula before you tweak the main program. Monday morning, list every reinforcer source in your room and note which ones fall outside your target schedule.
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02At a glance
03Original abstract
In multiple schedules of reinforcement, ratios of responses in successive components are relatively insensitive to ratios of obtained reinforcers. An analysis is proposed that attributes changes in absolute response rates to concurrent interactions between programmed reinforcement and extraneous reinforcement in other components. The analysis predicts that ratios of responses in successive components vary with reinforcer ratios, qualified by a term describing the reinforcement context, that is, programmed and extraneous reinforcers. Two main predictions from the analysis were confirmed in an experiment in which pigeons' responses were reinforced in the components of a multiple schedule and analog extraneous reinforcement was scheduled for an alternative response in each component. Sensitivity of response and time ratios to reinforcer ratios in the multiple schedules varied as a function of the rate of extraneous reinforcers. Bias towards responding in one component of the multiple schedule varied as an inverse function of the ratios of extraneous reinforcer rate in the two components. The data from this and previous studies of multiple-concurrent performance were accurately predicted by our analysis and supported our contention that the allocation of behavior in multiple-schedule components depends on the relative values of concurrently-available reinforcers within each component.
Journal of the experimental analysis of behavior, 1983 · doi:10.1901/jeab.1983.39-405