Conditioned reinforcement by conditional discriminative stimuli.
Deliver informative feedback right away—its value as a reinforcer drops sharply with even a short delay.
01Research in Context
What this study did
The researcher let pigeons pick between two paths. Each path ended with the same food, but the birds first saw a color light that told them food was coming.
The twist was timing. One path showed the color cue right away. The other made the bird wait a few extra seconds before the cue appeared.
What they found
The birds almost always chose the path with the earlier color cue. The food stayed the same; only the wait for the informative light changed.
This shows the cue itself worked like a tiny reward. The sooner it arrived, the stronger its pull.
How this fits with other research
Pear et al. (1984) already showed pigeons pick cues tied to richer food rates. Iwata (1988) adds the timing angle: even when rates are equal, earlier feedback wins.
Lazar (1977) found that removing distinctive cues mid-chain crashed accuracy. Together these studies say cues are not just helpers—they are reinforcers you can strengthen by delivering them faster.
White (1990) later showed a neutral "white flash" between tasks sharpens stimulus control. Both papers agree: managing the moment feedback appears controls later behavior.
Why it matters
You can boost the power of praise, tokens, or checkmarks by giving them right after the response, not after a delay. If you must wait, insert a brief informative signal immediately and hold the backup reinforcer later. Early feedback keeps clients engaged and speeds learning, even when the final prize stays unchanged.
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02At a glance
03Original abstract
A concurrent-chains schedule was used to examine how a delay to conditional discriminative stimuli affects conditioned reinforcement strength. Pigeons' key-peck responses in the initial link produced either of two terminal links according to independent variable-interval 30-s schedules. Each terminal link involved an identical successive conditional discrimination and was segmented into three links: a delay interval (green), a color conditional discriminative stimulus (blue or red), and a line conditional discriminative stimulus (vertical or horizontal lines). Food delivery occurred 45 s after entering the terminal link with a probability of .5, but its conditional probability (1.0 or 0) depended on the combination of the color and the line stimuli. One of the color stimuli occurred independently of further responding, 5 s after entry into the right terminal link, but it occurred 35 s after entry into the left terminal link. One of the line stimuli occurred independently of responding 40 s after entry into either terminal link, synchronized with the offset of the color stimulus. The initial-link relative response rate for the right was consistently higher in comparison with a control condition in which the color stimuli occurred 20 s after entry into either terminal link. The preference for the short delay to the color conditional discriminative stimuli suggests the possibility of conditioned reinforcement by information about the relation between the line conditional discriminative stimuli and the outcomes.
Journal of the experimental analysis of behavior, 1988 · doi:10.1901/jeab.1988.49-239