Interactions between the effects of food and water motivating operations on food‐ and water‐reinforced responding in mice
A recent snack can raise later working for water, but a drink will not raise working for food.
01Research in Context
What this study did
Lewon et al. (2019) tested how hunger and thirst change what mice work for. They gave mice a lever that dropped food pellets or a sip of water. First they made the mice hungry, thirsty, or both. Then they let the mice press for either food or water.
Next the team gave some mice food right before the session. Others got water first. They counted how this changed later pressing for either reinforcer.
What they found
Hungry mice pressed more for food. Thirsty mice pressed more for water. When both needs were high, pressing for either reinforcer went up even more.
The twist: giving food just before the session made mice press more for water later. Giving water first did not make them press more for food. Hunger and thirst talk to each other, but not in a two-way street.
How this fits with other research
Lowe et al. (1995) showed that water and food both create the same within-session ups and downs under VI schedules. Lewon adds that the starting deprivation level decides which reinforcer wins.
McSweeney et al. (1993) warned that responding drifts within a session. Lewon shows that a quick snack can flip that drift for water responding, so you must track what happened minutes earlier.
Hymowitz (1976) found that shock cuts schedule-induced water intake, but lighter body weight (more deprivation) softens the cut. Lewon agrees that deprivation strength sets the final response level, even when the change comes from another reinforcer.
Why it matters
If you give a client a snack before therapy, you may boost their later motivation for drinks or other reinforcers. Watch for these cross-overs, especially in dual-need cases like kids who skip breakfast and refuse water. Track what was eaten or drank in the last 30 minutes. A quick bite might jump-start work for a different reward without extra deprivation.
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02At a glance
03Original abstract
Two experiments examined interactions between the effects of food and water motivating operations (MOs) on the food- and water-reinforced operant behavior of mice. In Experiment 1, mice responded for sucrose pellets and then water reinforcement under four different MOs: food deprivation, water deprivation, concurrent food and water deprivation, and no deprivation. The most responding for pellets occurred under food deprivation and the most responding for water occurred under water deprivation. Concurrent food and water deprivation decreased responding for both reinforcers. Nevertheless, water deprivation alone increased pellet-reinforced responding and food deprivation alone likewise increased water-reinforced responding relative to no deprivation. Experiment 2 demonstrated that presession food during concurrent food and water deprivation increased in-session responding for water relative to sessions where no presession food was provided. Conversely, presession water during concurrent food and water deprivation did not increase in-session responding for pellets. These results suggest that a) the reinforcing value of a single stimulus can be affected by multiple MOs, b) a single MO can affect the reinforcing value of multiple stimuli, and c) reinforcing events can also function as MOs. We consider implications for theory and practice and suggest strategies for further basic research on MOs.
Journal of the Experimental Analysis of Behavior, 2019 · doi:10.1002/jeab.522