A model for food and stimulus changes that signal time-based contingency changes.
A one-second neutral cue timed at the reinforcer flip speeds up choice switching.
01Research in Context
What this study did
Pigeons pecked keys for food. Every few minutes the payoff odds flipped.
The birds got a tiny extra light or sound right when the flip happened.
Sarah’s team tracked how fast the birds noticed the new odds. They built a math model to fit the data.
What they found
With the brief cue, birds switched to the better side sooner.
The new model predicted choice better than older ones. It shows the cue sharpens time sense.
How this fits with other research
Dougherty et al. (1994) first said pigeons can’t track time perfectly. Sarah keeps that idea but adds the cue trick.
Farmer et al. (1966) mapped where to place a stimulus in a fixed schedule. Sarah shows the flip moment is the best spot.
White (1995) found stimulus control fades the longer a schedule runs. Sarah’s cue resets that fade, like hitting refresh.
Why it matters
You can use a quick neutral cue—beep, flash, word—to mark when reinforcement odds change. This helps learners notice the shift faster and adjust their behavior. Try it during schedule thinning or when you switch from rich to lean reinforcement. One second of extra signal can save minutes of off-task behavior.
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02At a glance
03Original abstract
When the availability of reinforcers depends on time since an event, time functions as a discriminative stimulus. Behavioral control by elapsed time is generally weak, but may be enhanced by added stimuli that act as additional time markers. The present paper assessed the effect of brief and continuous added stimuli on control by time-based changes in the reinforcer differential, using a procedure in which the local reinforcer ratio reversed at a fixed time after the most recent reinforcer delivery. Local choice was enhanced by the presentation of the brief stimuli, even when the stimulus change signalled only elapsed time, but not the local reinforcer ratio. The effect of the brief stimulus presentations on choice decreased as a function of time since the most recent stimulus change. We compared the ability of several versions of a model of local choice to describe these data. The data were best described by a model which assumed that error in discriminating the local reinforcer ratio arose from imprecise discrimination of reinforcers in both time and space, suggesting that timing behavior is controlled not only by discrimination elapsed time, but by discrimination of the reinforcer differential in time.
Journal of the experimental analysis of behavior, 2014 · doi:10.1002/jeab.105