Signal functions in delayed discriminative stimulus control by reinforcement sources.
Delays weaken stimulus control unless you provide a continuous signal; partial or no signals degrade accuracy.
01Research in Context
What this study did
Kuroda et al. (2014) worked with pigeons in a lab.
The birds had to pick the correct key when the reward was delayed.
Some delays had a full light signal, some had a brief flash, and some had no signal at all.
What they found
Accuracy was best when the light stayed on for the whole delay.
Performance dropped when the signal was only a quick flash.
With no signal, the birds made the most mistakes.
How this fits with other research
Lattal (1984) showed the same thing for simple key pecking: a blackout signal kept response rates high.
Cullinan et al. (2001) added that birds prefer choices with signaled delays.
Grosch et al. (1981) first proved this preference; the 2014 study now shows the signal also sharpens conditional discrimination.
Together, four decades of pigeon work say: if you must delay reinforcement, give a clear, continuous cue.
Why it matters
When you stretch the time between a correct response and the reinforcer, add a salient signal.
Use a timer bar, a light, or a tone that stays on until the item arrives.
This keeps the learner’s behavior accurate and prevents errors from filling the gap.
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02At a glance
03Original abstract
The discriminative functions of the response-reinforcer relation may contribute to the changes in response rates that occur when reinforcement is delayed. These properties were investigated in three experiments with pigeons using a discrete-trials conditional discrimination procedure. A concurrent variable-interval schedule was arranged on two side keys during a sample component. The key peck that ended the schedule (the sample response) initiated a delay with either a stimulus present throughout the delay interval (full signal), a stimulus present only during the first second of the interval (partial signal), or no stimulus present (unsignaled delay). The delay was followed by a choice component where one alternative was reinforced if the left sample response produced the choice component and the other if the right sample response produced the choice component. Accuracy was high with a full signal; slightly lower with a partial signal; and lowest without a signal. The results parallel the effects of similar delays programmed in conventional reinforcement schedules. This in turn suggests a possible discriminative effect of the response-reinforcer relation in the control of behavior by (delayed) reinforcement.
Journal of the experimental analysis of behavior, 2014 · doi:10.1002/jeab.85