Conditioned reinforcement and choice with delayed and uncertain primary reinforcers.
A 10-second colored light paired with food can act as a conditioned reinforcer and keep animals choosing a risky, low-probability option.
01Research in Context
What this study did
Pigeons chose between two keys. One key gave food half the time and flashed a green light. The other key always gave food but had no light.
The green light lasted 10 seconds. Researchers slowly lengthened the delay before food on the green-light side. They tracked which key the birds pecked.
What they found
When the green light came with no food, birds soon stopped picking that key. When the light came with food—even delayed—the birds kept choosing it.
The colored light worked like a tiny reward. It pushed the birds to stay on the risky side even though food odds were only 50/50.
How this fits with other research
Ginsburg et al. (1971) and Jenkins et al. (1973) already showed that pigeons will peck just to see a food-paired light. Mazur (1995) moves the idea into choice: the light can swing a whole decision.
Allan et al. (1994) saw the same birds prefer 50 % payoff when delays stay short. Adding the green light gives a tidy reason why—conditioned reinforcement.
Funderburk et al. (1983) found that short signals hurt preference while long signals help. E’s 10-second light fits the "long" side, so the boost in choice matches their reversal pattern.
Why it matters
You can make uncertain rewards feel safer by pairing them with a brief, salient cue. Try adding a favorite sound, color, or brief video clip right before the harder-to-get reinforcer. One practical move: set a 5–10 second animated icon on the tablet screen before the only 50 % payoff trial. The stimulus itself may keep clients responding while you stretch delays or thin the schedule.
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02At a glance
03Original abstract
In an adjusting-delay choice procedure, pigeons could peck on either a red key or a green key. A peck on the red key always led to a delay associated with red houselights and then food. The delay was adjusted over trials to estimate an indifference point--a delay at which the two keys were chosen about equally often. In some conditions, a peck on the green key led to food on all trials after delays of either 10 s or 30 s, and green houselights were lit during the delays. In other conditions, food was presented on only half of the green-key trials. If the green houselights continued to occur on both reinforcement and nonreinforcement trials, preference for the green key always decreased. Preference for the green key also decreased if half of the trials had 30-s houselights followed by food and the other half had no green houselights and no food. However, preference for the green key actually increased if half of the trials had 10-s green houselights followed by food and the other half had no green houselights followed by no food. The latter condition therefore demonstrated a case in which preference for an alternative increased when food was removed from half of the trials. The results suggest that the red and green houselights served as conditioned reinforcers. A hyperbolic decay model (Mazur, 1989) provided good predictions for all conditions by assuming that the strength of a conditioned reinforcer is inversely related to the total time spent in its presence before food is delivered.
Journal of the experimental analysis of behavior, 1995 · doi:10.1901/jeab.1995.63-139