Preference reversals with food and water reinforcers in rats.
Preference can flip from now to later when the later payoff is bigger, and this holds across food, water, and people.
01Research in Context
What this study did
Green et al. (2003) worked with lab rats.
They gave the rats two options: a tiny bit of food or water right away, or a bigger amount after a short wait.
The team slowly made the wait longer to see when the rats would switch their pick.
What they found
Every rat changed its mind.
At first they took the small, fast reward.
When the delay grew, they all flipped to waiting for the bigger reward.
The switch happened with both food and water, showing the effect is not tied to one type of treat.
How this fits with other research
Drifke et al. (2019) later saw the same flip in preschool kids.
After kids learned that choosing earned them better prizes, they started to pick the choice option more.
That human result extends Leonard’s rat work: history with better payoff can reverse preference.
Vos et al. (2013) tested children with autism and found splits: some liked choice, some did not.
Their mixed outcome reminds us that reinforcer quality and person matter; the reversal is not automatic.
Why it matters
You now have lab proof that preference is movable, not fixed.
If a client keeps grabbing the tiny candy now, try adding a short wait and then deliver a much better item.
Track the wait times where the switch happens; that point is your clinical target.
Use this lever to build patience, teach waiting, and shape self-control in any setting where delays occur.
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02At a glance
03Original abstract
Rats were given a choice between a smaller, immediately available reward and a larger reward available after a delay. In one phase, the reward was food and in another phase, the reward was water. Constant delays were added between the choice presentation and the delivery of the reward alternatives. As the time between choice and reward delivery increased from 0 to 25 s, all rats (except one in the water phase) reversed their preference from the smaller, sooner alternative to the larger, later alternative. These findings extend the generality of the preference-reversal animal model to qualitatively different reinforcers. Furthermore, the presence of both impulsive and self-control choices within the same animal is consistent with the view that self-control may be understood as choice behavior, and that species differences in self-control may be differences in degree, not kind.
Journal of the experimental analysis of behavior, 2003 · doi:10.1901/jeab.2003.79-233