Within-subject reversibility of discriminative function in the composite-stimulus control of behavior.
Composite-stimulus control flips the moment the payoff swaps, proving it is fully reversible within a single session.
01Research in Context
What this study did
The team worked with lab rats pressing a lever. A light-plus-tone combo signaled when presses paid off. After the rats learned one combo, the researchers swapped which combo produced food. They watched if the rats switched their pressing right away.
Each rat served as its own control. The swap happened several times within the same animal. No new training was given after each swap.
What they found
Lever presses tracked the most recently reinforced composite stimulus. When the payoff swapped, the rats swapped with it in the same session.
Control was complete and immediate. There was no carry-over from the earlier contingency.
How this fits with other research
The finding lines up with Gulley et al. (1997). They also reversed which stimulus paid off and saw behavior flip at once. Both studies show stimulus control can be undone and rebuilt in minutes.
LeBlanc et al. (2003) add that richer reinforcement makes stimulus control stronger. J et al. now show that even strong control can still be reversed if the contingency flips.
Thrailkill et al. (2018) seem to disagree. They found that higher reinforcement rates during training later cause more relapse. The two papers differ in what they measure. Thrailkill looked at spontaneous recovery after extinction; J et al. looked at within-session reversals while reinforcement was still present. High rates do not prevent reversal while the contingency is active, but they may protect the old pattern once extinction starts.
Why it matters
You can trust that newly taught stimulus–response links are not locked in stone. If you need to change which picture, word, or cue signals reinforcement, go ahead—clients are likely to follow the new rule fast. Just keep the old contingency truly unavailable; any accidental payoff will pull behavior back.
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02At a glance
03Original abstract
According to the composite-stimulus control model (Weiss, 1969, 1972b), an individual discriminative stimulus (S(D)) is composed of that S(D)'s on-state plus the off-states of all other relevant S(D)s. The present experiment investigated the reversibility of composite-stimulus control. Separate groups of rats were trained to lever-press for food whenever a tone or a light S(D) was present. For one group, the nonreinforced S(Delta) condition was tone-and-light absence (T+L). Tone-plus-light (T+L) was S(Delta) in the other group. On a "stimulus compounding" test that recombined composite elements, maximum responding occurred to that composite consisting only of elements occasioning response increase. That was T+L for the group trained with T+L as S(Delta) and T+L for the group trained with T+L as S(Delta). The S(Delta) composite was next reversed over groups in Phase 2. In Phase 2 tests, maximum responding that was comparable in magnitude to that of Phase 1 was again controlled by the composite consisting only of elements most recently occasioning response increase-whether T+L or T+L. The inhibitory conditioning history of both composite-elements currently occasioning responding did not weaken the summative effect. These results confirm and extend Weiss's composite-stimulus control model, and demonstrate that such control is fully reversible. We discuss how translating conditions of the stimulus-compounding paradigm to a composite continuum creates a functional and logical connection to intradimensional control measured through stimulus generalization, reducing the number of different behavioral phenomena requiring unique explanations.
Journal of the experimental analysis of behavior, 2009 · doi:10.1901/jeab.2009.92-367