Anticipatory drinking in rats: compensatory adjustments in the local rate of intake

The current experiment examined whether dehydrated rats could learn to anticipate disruption of access to water. Previous research showed that rats running in a wheel in order to drink compensated for local disruptions on intake by increasing their rate of intake after, but not prior to the initial disruption. The present experiment exposed rats to either a fixed-ratio (FR) schedule that required rats to run in order to drink or a matched, fixed-time (FT) schedule that allowed the animals intermittent access to water without running. Access to water was disrupted by restricting the quantity of water available per drink bout. Rats increased their local rate of water intake prior to the disruption under the FT schedule but not under the FR schedule. The results suggest that rats can learn to increase their local rate of intake in anticipation of local restrictions on water under response-independent (FT) schedules. It was hypothesized that these anticipatory increases in the local rate of intake resulted from a priming effect due to the motivating effects of stimuli associated with water and/or frustration resulting from attempts to drink prior to water availability.