Discrimination of response-reinforcer and response-stimulus contingencies in pigeons.
Animals can learn to tell DRL from DRO schedules even when timing changes, so teach the rule, not just the clock.
01Research in Context
What this study did
Pigeons pecked two keys. One key color meant DRL: wait long enough, then peck to get food. Another color meant DRO: any peck resets the clock, so stay quiet to get food.
The birds learned to tell the two rules apart. Later the timing rules changed, but the birds still chose the correct key.
What they found
The pigeons kept picking the key that matched the real rule, even when wait times were switched. They were not just counting seconds or pecks. They noticed the difference between "peck after waiting" and "don’t peck while waiting."
This shows animals can learn the actual contingency, not just the surface cues.
How this fits with other research
Richardson (1973) and REYNOLDS (1964) already showed DRL alone slows pigeon pecking. Dodd (1984) goes further by proving birds can tell DRL from DRO, not just slow down.
Schwartz et al. (1971) found an extra key helps birds time short waits. Dodd (1984) shows birds still discriminate when timing changes, so they rely on rule cues, not just timing tricks.
Rey et al. (2020) later showed long DRO works because the contingency is clear, not because of accidental rewards. This backs Dodd (1984): contingency clarity, not lucky reinforcement, drives the effect.
Why it matters
When you use DRL or DRO with a client, remember the person must notice the rule, not just the clock. Make the rule obvious: use clear signals, keep words simple, and test if they can tell the two setups apart. If they can’t, teach the difference first.
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02At a glance
03Original abstract
For three pigeons (Experiment 1), the presentation of a red response key ended with a food presentation either following two responses separated by at least 10 seconds (a DRL contingency) or following a 10-second response-free period (a DRO contingency). For three other birds (Experiment 2), a brief stimulus presentation terminated the DRL and DRO contingencies. A white side key was presented next and ended with response-dependent food following one contingency and a timeout following the other. Since the contingency on the red key was unsignaled, differential responding on the white side key could indicate that the two response-reinforcer relations had been discriminated. In Experiment 1, the red-key duration and number of responses influenced white-key responding following the contingency that predicted the timeout. A response-initiated DRO was instated, and the influence of red-key duration and response number on white-key responding was diminished. In both experiments, the 10-second time criterion in both contingencies was varied from 0.34 second to 10 seconds. Even at short time intervals the DRO and DRL contingencies were readily discriminated. Pigeons tended to class the two contingencies according to a rule that did not involve simply stimulus duration, numbers of responses, or even the time between a response and its consequence.
Journal of the experimental analysis of behavior, 1984 · doi:10.1901/jeab.1984.41-7