Discrete-trials spaced responding in the pigeon: the dependence of efficient performance on the availability of a stimulus for collateral pecking.
A spare, non-reinforced response key can act as a mediating stimulus that lets pigeons meet a 6-sec DRL requirement.
01Research in Context
What this study did
Researchers worked with pigeons on a six-second DRL schedule.
Birds had to wait six seconds between pecks or lose the reinforcer.
A second key sat nearby. Pecking it did nothing, but it was always there.
What they found
Without the extra key, birds scored under ten percent correct.
When the spare key was present, accuracy jumped to seventy-five percent.
The idle key gave the birds something to do while they waited.
How this fits with other research
REYNOLDS (1964) ran a similar DRL setup but left out the spare key.
Those birds still learned to wait, yet their timing was rougher.
The new study shows that a simple collateral stimulus sharpens timing.
Rilling et al. (1969) showed DRL rules do not hurt stimulus control.
Together the papers tell us: timing tools and stimulus control can coexist.
Why it matters
Your learner may fail a DRL not from stubbornness, but from empty time.
Give the hands or mouth a neutral job—squeeze ball, tap desk, hum softly.
The idle response fills the gap so the timed response can land on schedule.
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02At a glance
03Original abstract
Four pigeons were exposed to a discrete-trial schedule in which only responses spaced by at least 6 sec were reinforced. After 45, fifty-trial sessions, they failed to meet the spacing requirement in over 90% of the trials. When an alternative, non-contingent key (pecks on which had no consequence) was illuminated concurrently with the first key, the spacing performance of the three pigeons that pecked the non-contingent key improved so that they were obtaining 75% of the possible reinforcers. These data demonstrated the importance of collateral behavior in mediating spaced performance. It was suggested that pigeons may successfully refrain from responding on the spacing procedure only when another stimulus correlated with reinforcement is available for pecking, and that the form that collateral behavior takes may, in general, be non-arbitrary, and species dependent.
Journal of the experimental analysis of behavior, 1971 · doi:10.1901/jeab.1971.16-155