Effects of shifts in food reinforcement context on rats’ consumption of concurrently available water or sucrose solution
Cutting rich food rewards makes rats drink more water, showing negative contrast—expect similar swings when you thin client reinforcement.
01Research in Context
What this study did
Galuska and colleagues worked with lab rats. They first gave the rats rich food reinforcement. Then they suddenly cut the food rate to lean.
While the food schedule changed, the rats could also drink water or sugar water. The team measured how much the animals drank.
What they found
When food rewards dropped from rich to lean, the rats drank more. Both plain water and sugar water intake rose.
The sudden loss of food value made the alternate drinks more attractive. This is a classic negative contrast effect.
How this fits with other research
Ballard et al. (1975) saw the same jump in drinking when rats got fewer food pellets. Their early work set the stage for this richer-to-leaner test.
Johnston et al. (2017) tested people, not rats. Rich alternative rewards knocked problem behavior down fastest, but the behavior bounced back hardest when those rewards stopped. The rat data now show the swing happens even while the shift is in place.
Arroyo Antúnez et al. (2026) used mice and found larger alternate rewards work faster but create bigger resurgence later. Together the three papers warn: rich-to-lean changes can both boost alternate behavior now and set up relapse later.
Why it matters
If you thin a dense reinforcement schedule, watch for contrast side effects. A client might suddenly seek other reinforcers—snacks, drinks, attention—right after you reduce token or edible rates. Track these adjunctive behaviors so you don’t mistake them for new problems. Plan gradual thinning and keep alternate reinforcers ready to buffer the swing.
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02At a glance
03Original abstract
The purpose of this study was to investigate the effects of signaled transitions from relatively rich to lean conditions of food reinforcement on drinking concurrently available water or sucrose-sweetened water in rats. Past research demonstrated that these negative incentive shifts produce behavioral disruption in the form of extended pausing on fixed-ratio schedules. Four male Long-Evans rats operated on a two-component multiple fixed-ratio fixed-ratio schedule. In one manipulation, the ratio was held constant and the components arranged either a large six-pellet reinforcer (rich) or small one-pellet reinforcer (lean). In a second manipulation, the components both produced a one-pellet reinforcer but differed in terms of the ratio requirement, with the rich and lean conditions corresponding to relatively small and large ratios. In both manipulations, components were pseudorandomly presented to arrange four transitions signaled by retractable levers: lean-to-lean, lean-to-rich, rich-to-rich, and rich-to-lean (the negative incentive shift). During experimental conditions, a bottle with lickometer was inserted in the chamber, providing concurrent access either to tap water or a 10% sucrose solution. The negative incentive shift produced considerably more drinking than the other transitions in all rats during both manipulations. The level of drinking was not polydipsic; rather, it appears that the negative incentive shift enhanced the value of concurrently available reinforcers relative to food reinforcement.
Journal of the Experimental Analysis of Behavior, 2017 · doi:10.1002/jeab.242