Effects of reinforcer probability on attending to element and compound sample stimuli
Past payoff odds for single cues silently steer later attention to whichever part of a compound stimulus was ‘richer.’
01Research in Context
What this study did
Thrailkill and team worked with pigeons in a matching-to-sample task. First, birds learned that one color (say, red) gave food a large share of the time, while another color (green) paid off only a large share.
Later, the same colors appeared together as a red-green compound. The birds had to pick which side the compound had been on. The question: would past payoff odds sway where the birds looked?
What they found
Pigeons looked longer at the half of the compound that used to pay more. If red had the rich history, eyes drifted to the red side of the red-green pair.
Choice followed the same bias. The birds pecked the side linked to the formerly richer element about 4:1, a clean matching-law fit.
How this fits with other research
Nevin (1969) showed that reinforcing one part of a compound can make pigeons ignore the rest. Thrailkill adds the why: the ignored piece probably had a leaner payoff history.
Locurto et al. (1980) found that even rare reinforcement for errors wrecks discrimination. The new data flip the lens—rich reinforcement for one element now guides attention, but both studies obey the same matching equation.
Jones et al. (1992) proved you can cue pigeons to forget part of a compound. Thrailkill shows you don’t need a forget cue; weak reinforcement history does the forgetting for you.
Why it matters
Your client’s history with part of a task can pull attention away from the rest. If you’ve been heavily reinforcing color cues while shape cues pay off less, don’t be surprised when the child starts missing shape changes. Check each element’s reinforcement rate, not just the final answer, and rebalance if you want equal noticing.
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02At a glance
03Original abstract
Previous research has shown that divided‐attention performance is sensitive to variations in relative reinforcement in a manner consistent with the generalized matching law. Two experiments with pigeons were designed to better understand the effects of different reinforcement conditions on divided‐attention performance. Experiment 1 asked whether separate experience with different relative reinforcement probabilities for elements alone would produce changes in performance during nondifferentially reinforced divided‐attention trials with compound samples consisting of those elements. The results suggest that accuracy following compound sample trials varied as a function of relative reinforcement experienced in element trials in a manner consistent with the matching law. Experiment 2 used an adjusting‐sample‐duration procedure to maintain constant accuracy on element and divided‐attention trials and varied the probability of reinforcement across conditions. The sample durations that were required to maintain constant accuracy increased as reinforcement probability decreased even though that longer sample durations were required to maintain accuracy for compound‐sample trials than for element‐sample trials (the element‐superiority effect). Overall, the present results are consistent with the notion that increased attention is allocated to stimuli that are associated with more reinforcement.
Journal of the Experimental Analysis of Behavior, 2025 · doi:10.1002/jeab.70023