Interactions between the effects of food and water motivating operations on concurrent food- and water-reinforced responding in mice.

In organisms' natural environments, many events that function as motivating operations (MOs) operate concurrently and many reinforcers are available concurrently. Previous research has shown that (a) multiple MOs may interact to affect a single operant class of behavior reinforced by a single event, (b) a single MO may affect multiple operant classes of behavior reinforced by different events, and (c) consumption of/interaction with reinforcers can have motivating functions. This suggests that the effects of MOs and how these are described are contextual in that they depend on the circumstances under which they are assessed. The current study sought to extend understanding of context-specific effects of MOs on the overall and within-session patterns of operant responding of mice when sucrose pellets and water were concurrently available as reinforcers under four different MO conditions: food deprivation, food and water deprivation, water deprivation, and no deprivation. Results demonstrated interactions between MOs in terms of their effects on the overall and within-session patterns of behavior reinforced by sucrose pellets and water, differential effects of MOs on responding for different reinforcers, and individual differences in the effects of MOs. More contextually oriented basic research on MOs may contribute to our understanding of their effects in real-world circumstances.