Effects of a delay-reinforcement procedure on performance under IRT>t schedules.

Researchers tested pigeons on a special schedule. The birds had to wait a set time between pecks to earn food.

Then the team added a twist. After each food delivery, they paused the next reinforcer for 0, 4, 8, or 16 seconds.

No lights or sounds told the birds when the delay was on. The schedule itself created the pause.

Longer pauses made the birds peck less. Response rate fell as the delay grew.

The drop was bigger for birds that pecked fast to start. Slow birds barely changed.

Guest et al. (2013) ran a similar test with brief delays. They saw the opposite: pecking went up, not down. The key difference is schedule type. A et al. used IRT>t schedules, while F et al. used yoked-VI schedules. Same delay, different rules, different results.

Halpern et al. (1966) showed that bigger fixed-ratio schedules also slow birds down. Their pause happened before the run, while A et al.'s pause happened after food. Both studies show that timing gaps can brake behavior.

Arnett (1972) added clock lights to fixed-interval schedules. Like A et al., the extra cues cut response rates. Both papers warn that added contingencies can suppress responding even without punishment.

If you use DRL or IRT-based programs, watch for hidden delays. Even a few seconds of post-reinforcement silence can shrink response rates. Check baseline speed before you add timing rules, because fast responders will drop the most.