Fixed-ratio performance under conditions of delayed reinforcement.

Dunham (1972) tested how delaying reinforcement affects fixed-ratio performance. Rats pressed a lever on fixed-ratio schedules. The food pellet came right away or after a delay of several seconds. The team watched how long rats paused after each reinforcer and how fast they ran the next ratio.

Longer delays made the post-reinforcement pause grow. Once the rats started responding again, their speed stayed about the same. Delay changed when they started, not how fast they went.

Halpern et al. (1966) showed that bigger ratio sizes also lengthen the pause. Dunham (1972) adds that timing the reinforcer later has the same pause-lengthening effect, even when the ratio stays the same size.

Kendall et al. (1978) later found pigeons kept high response rates despite long delays. Their strong effect looks like it overturns J’s neutral rate finding, but the later study used timeout periods that may have protected the response–reinforcer link.

Crossman et al. (1985) seems to clash: they report pauses shorten as ratio size grows from FR 1 to FR 7. The conflict disappears when you see they tested only very small ratios; the classic pause-grows-with-size rule applies to larger ratios like those in Dunham (1972).

If you run a token system or any fixed-ratio program, remember that the moment of reinforcement matters. Deliver the token or praise right after the last response and the learner will start the next bout sooner. A short delay is harmless to response speed, but it will stretch the break. Time your delivery to keep momentum in academic work, vocational tasks, or exercise reps.