Acquisition and Extinction of Schedule-Induced Polydipsic Consumption of Alcohol and Water

Abstract

16 Charles River (cd) rats were trained to bar-press on an FI 60 schedule for varying number of days, half with water present and half with alcohol. Predictably, schedule-induced fluid consumption resulted. 10 days of extinction of bar-pressing followed. During FI 60 both groups bar-pressed approximately equally often but greater fluid consumption occurred in the group on water. During extinction, both groups showed reduced bar-pressing behavior. Whereas water consumption was extinguished in two days, alcohol consumption remained high and quite variable after bar-pressing had stopped. Results suggest that bar-pressing and fluid consumption are independent behaviors which finding argues against explanations of schedule-induced polydipsia based on adventitious reinforcement. For some rats, the termination of alcohol intake prior to the end of an FI 60 session without an associated cessation of bar-pressing suggested that schedule-induced polydipsia may have been a function of the aversiveness of the reinforcement schedule.