Self-control in mentally retarded adolescents: choice as a function of amount and delay of reinforcement.
Teens with severe ID show normal delay discounting: long waits push them to smaller-sooner rewards, but equal long waits can restore larger-later choices.
01Research in Context
What this study did
Three teens with severe intellectual disability sat at a table. Each trial they could pick one of two options.
One option gave a little candy right away. The other gave more candy after a wait.
The researchers made the wait longer and longer across sessions to see when the teens would switch.
What they found
As the delay for the big candy grew, all three teens started taking the small candy instead.
Later the team added the same long wait to both piles. The teens went back to picking the bigger pile.
The teens acted like typical people: long waits made the reward feel smaller.
How this fits with other research
Logue et al. (1986) ran the same game with adult women. Those adults kept picking the big delayed reward. The teens with ID looked more impulsive, but the task was fair.
Lord et al. (1997) later asked people with ID to choose between two favorite toys, not between now vs later. Choice of toy gave no extra work, so the study found no benefit. The 1988 paper shows timing, not item choice, drives the change.
Fox et al. (2001) and Dunkel-Jackson et al. (2016) stretched the wait even longer for kids and adults with autism. They added a simple job during the delay. Like the 1988 study, longer waits first hurt self-control, then training brought it back.
Why it matters
You now know clients with ID will grab the small-sooner prize if the big reward is far away. Start with short waits and grow them slowly. Add a quick task during the delay to help the learner stick with the big goal.
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02At a glance
03Original abstract
Three severely mentally retarded adolescents were studied under discrete-trial procedures in which a choice was arranged between edible reinforcers that differed in magnitude and, in some conditions, delay. In the absence of delays the larger reinforcer was consistently chosen. Under conditions in which the smaller reinforcer was not delayed, increasing the delay to delivery of the larger reinforcer decreased the percentage of trials in which that reinforcer was chosen. All subjects directed the majority of choice responses to the smaller reinforcer when the larger reinforcer was sufficiently delayed, although the value at which this occurred differed across subjects. Under conditions in which the larger reinforcer initially was sufficiently delayed to result in preference for the smaller one, progressively increasing in 5-s increments the delay to both reinforcers increased percentage of trials with the larger reinforcer chosen. At sufficiently long delays, 2 of the subjects consistently chose the larger, but more delayed, reinforcer, and the 3rd subject chose that reinforcer on half of the trials. These results are consistent with the findings of prior studies in which adult humans responded to terminate noise and pigeons responded to produce food.
Journal of the experimental analysis of behavior, 1988 · doi:10.1901/jeab.1988.49-191