Two-component schedules of differential-reinforcement-of-low-rate.

Brinker et al. (1975) worked with pigeons on a two-part DRL schedule. Part one required a short pause between pecks. Part two required a longer pause.

The birds switched back and forth between the two parts many times per session. The key color told them which pause rule was active.

The pigeons matched their pause times to whichever rule was currently in force. Their previous reinforced, or non-reinforced, pecks acted like traffic lights that told them how long to wait next.

In plain words, the birds used their own reinforcement history as a cue to time the next response.

Hart et al. (1974) saw the opposite: when DRL requirements got longer, lever pressing and licking dropped while wheel running shot up. The two studies seem to clash, but the difference is the task. B et al. used one long DRL value at a time and measured side behaviors. P et al. rapidly alternated two short DRL values and looked at timing control.

LATIES et al. (1965) showed rats grow extra behaviors like tail nibbling to fill long DRL gaps. P et al. add the idea that the outcome of the last response itself becomes the cue for the next pause.

Newman et al. (1991) later used the same fine-grained pause analysis to separate drug effects. They built on P et al.'s method to see whether medicines improve timing or just scatter responses.

If you run DRL to reduce rapid calling or hand flapping, remember the client's last response is now a signal. Reinforce the correct pause immediately so that "success" becomes the cue for the next correct pause. Switching between two DRL values within one session, signaled by color or place, can sharpen this stimulus control and speed up learning.