Adaptive criterion setting in perceptual decision making.
Small changes in reward odds make behavior swing fast—watch your data closely after any schedule tweak.
01Research in Context
What this study did
Researchers worked with pigeons on a simple task. The birds pecked left or right based on whether a light looked bright or dim.
They changed the rules. Sometimes bright choices paid more. Sometimes dim choices paid more. The team watched how fast pigeons switched their minds.
What they found
The birds flipped their choices almost right away. First they over-corrected, then they settled close to the best possible split.
Tiny reward changes—just a few percent—pushed big shifts in behavior.
How this fits with other research
This builds on Macdonald et al. (1973) and Aragona et al. (1975). Those studies showed pigeons match response rates to reward rates on standard schedules.
Yuwiler et al. (1992) and Davison et al. (1989) seemed to clash. They found pigeons did not always pick the richest option. The difference is the task. Earlier work used time-based or overall-rate rules. The 2011 study used moment-to-moment probability shifts.
Dardano (1972) saw the same fast adjustment in monkeys doing duration choices. Across species, small reward tweaks drive quick criterion moves.
Why it matters
If you change token boards, DRA schedules, or reinforcement odds, expect rapid drift. Check data daily for the first week after any shift.
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02At a glance
03Original abstract
Pigeons responded in a perceptual categorization task with six different stimuli (shades of gray), three of which were to be classified as "light" or "dark", respectively. Reinforcement probability for correct responses was varied from 0.2 to 0.6 across blocks of sessions and was unequal for correct light and dark responses. Introduction of a new reinforcement contingency resulted in a biphasic process of adjustment: First, choices were strongly biased towards the favored alternative, which was followed by a shift of preference back towards unbiased choice allocation. The data are well described by a signal detection model in which adjustment to a change in reinforcement contingency is modeled as the change of a criterion along a decision axis with fixed stimulus distributions. Moreover, the model shows that pigeons, after an initial overadjustment, distribute their responses almost optimally, although the overall benefit from doing so is extremely small. The strong and swift effect of minute changes in overall reinforcement probability precludes a choice strategy directly maximizing expected value, contrary to the assumption of signal detection theory. Instead, the rapid adjustments observed can be explained by a model in which reinforcement probabilities for each action, contingent on perceived stimulus intensity, determine choice allocation.
Journal of the experimental analysis of behavior, 2011 · doi:10.1901/jeab.2011.96-155