Choice in a variable environment: visit patterns in the dynamics of choice.
Reinforcers trigger rapid choice shifts that only show up when you analyze extended and local visit patterns.
01Research in Context
What this study did
Researchers watched six pigeons peck two keys. Each key paid food on its own variable-interval schedule. The team recorded every visit: how long a bird stayed on one key before switching.
They looked at two time scales. Extended patterns covered many reinforcers. Local patterns zoomed in on single reinforcer deliveries.
What they found
After a reinforcer arrived, the bird usually kept pecking the same key for a while. Then it switched. These quick shifts showed up best in visit-level data.
The pattern matched a molar view: recent reinforcers steered choice fast, even though overall preference looked stable.
How this fits with other research
Gomes-Ng et al. (2017) later argued the same thing: visit analyses catch reinforcer effects that older pulse-correction methods miss. The 2004 data became their Exhibit A.
Busch et al. (2010) ran 100 sessions with the same setup. Early sessions already showed the quick post-reinforcer shift, but the size of the shift kept growing. The 2004 snapshot was right, yet understated how patterns evolve.
Rutland et al. (1996) also tracked within-session changes, but counted responses and changeovers instead of visits. Both papers agree: reinforcers drive local dynamics; they just measured with different rulers.
Why it matters
When you graph a client's concurrent-schedule data, slice it into visits, not just 10-s bins. A sudden jump in stay length after a reinforcer tells you the consequence still controls choice. If the jump fades fast, you know the next reinforcer is up for grabs—perfect timing to thin or shuffle ratios.
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02At a glance
03Original abstract
Molar and molecular views of behavior imply different approaches to data analysis. The molecular view privileges moment-to-moment analyses, whereas the molar view supports analysis of more and less extended activities. In concurrent performance, the molar view supports study of both extended patterns of choice and more local patterns of visiting the choice alternatives. Analysis of the present data illustrated the usefulness of investigating order at various levels of extendedness. Seven different reinforcer ratios were presented within each session, without cues to identify them, and pigeons pecked at two response keys that delivered food on variable-interval schedules. Choice changed rapidly within components as reinforcers were delivered and, following each reinforcer, shifted toward the alternative that produced it. If several reinforcers were delivered consecutively by one alternative, choice favored that alternative, but shifted more slowly with each new reinforcer. A discontinuation of such a series of reinforcers by the delivery of a reinforcer by the other alternative resulted in a large shift of choice toward that alternative. These effects were illuminated by analysis of visits to the two alternatives. Changes in visit length occurred primarily in the first postreinforcer visit to the repeatedly reinforced alternative. All other visits tended to be brief and equal. Performance showed multiple signs of moving in the direction of a fix-and-sample pattern that characterized steady-state performance in earlier experiments with many sessions of maintaining each schedule pair. The analyses of extended and local patterns illustrate the flexibility of a molar view of behavior.
Journal of the experimental analysis of behavior, 2004 · doi:10.1901/jeab.2004.81-85