Contriving establishing operations: responses of individuals with developmental disabilities during a learning task.

The team worked with adults who have mild to moderate intellectual disability. They used a learning task called incremental repeated acquisition. Before each session they made the reinforcer hard to get for different lengths of time.

Some people waited 15 minutes to 2 hours. Others waited 1, 2, or 3 full days. Then everyone did the same teaching trials while the teachers counted correct responses.

Longer waits won. After 1–3 days without the item, people answered more often and made fewer errors. Short waits of minutes or hours gave weaker results.

The data showed a clear line: the longer the deprivation, the better the learning.

Xue et al. (2024) and Majdalany et al. (2016) ran similar tests with children with autism. They changed how long the reinforcer was delayed after a correct answer, not how long it was withheld before session. Both teams still found the same rule: any delay hurts learning.

van Timmeren et al. (2016) pushed the idea into discrete-trial lessons. They showed that even a few seconds of delay during teaching slows skill growth. The 2008 study widens the lens—days matter as much as seconds.

Davis et al. (1972) first saw the effect in rats decades ago. The new data say the old rule holds for humans with ID too.

You can use this tomorrow. Pick a powerful reinforcer and keep it out of reach for at least a day before your teaching session. Store the iPad, favorite chips, or special toy in a locked cabinet. When session starts, deliver it right after each correct response. The wait before plus no wait after gives you the strongest boost for learners with intellectual disability.