Examining the discriminative and strengthening effects of reinforcers in concurrent schedules.
A single reinforcer instantly nudges the next move, yet a streak from one source builds lasting preference.
01Research in Context
What this study did
The team ran a classic concurrent VI-VI setup with pigeons.
Two keys paid off on their own clocks.
They tracked every peck to see what one reinforcer did to the next choice.
What they found
One food pellet right away pulled the next peck to the same key.
A long string of pellets from that key slowly built a habit.
So a reinforcer is both a traffic light and a brick in the road.
How this fits with other research
Gomes‐Ng et al. (2017) later sharpened the view.
They showed that counting whole visits catches the effect better than looking at single pecks.
Cudré-Mauroux (2010) argued reinforcers might only be traffic lights, not bricks.
Nathalie’s data say they do both jobs, so the papers talk past each other only in wording.
Why it matters
In your session, remember that one treat can swing the next response.
But to lock in a skill you need a steady run of wins on the same side.
Watch for quick bias after any single reinforcer, then stay put long enough to build strength.
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Join Free →After each reinforcer, pause two seconds and note if the child drifts back to the same task; if you want lasting preference, keep the next three reinforcers on that side.
02At a glance
03Original abstract
Reinforcers may increase operant responding via a response-strengthening mechanism whereby the probability of the preceding response increases, or via some discriminative process whereby the response more likely to provide subsequent reinforcement becomes, itself, more likely. We tested these two accounts. Six pigeons responded for food reinforcers in a two-alternative switching-key concurrent schedule. Within a session, equal numbers of reinforcers were arranged for responses to each alternative. Those reinforcers strictly alternated between the two alternatives in half the conditions, and were randomly allocated to the alternatives in half the conditions. We also varied, across conditions, the alternative that became available immediately after a reinforcer. Preference after a single reinforcer always favored the immediately available alternative, regardless of the local probability of a reinforcer on that alternative (0 or 1 in the strictly alternating conditions, .5 in the random conditions). Choice then reflected the local reinforcer probabilities, suggesting some discriminative properties of reinforcement. At a more extended level, successive same-alternative reinforcers from an alternative systematically shifted preference towards that alternative, regardless of which alternative was available immediately after a reinforcer. There was no similar shift when successive reinforcers came from alternating sources. These more temporally extended results may suggest a strengthening function of reinforcement, or an enhanced ability to respond appropriately to "win-stay" contingencies over "win-shift" contingencies.
Journal of the experimental analysis of behavior, 2011 · doi:10.1901/jeab.2011.96-227