CONCURRENT-CHAINS SCHEDULES AS A METHOD TO STUDY CHOICE BETWEENALCOHOL-ASSOCIATED CONDITIONED REINFORCERS

摘要

An extensive body of research using concurrent-chains schedules of reinforcement has shown thatchoice for one of two differentially valued food-associated stimuli is dependent upon the overalltemporal context in which those stimuli are embedded. The present experiments examined whetherthe concurrent chains procedure was useful for the study of behavior maintained by alcohol andalcohol-associated stimuli. In Experiment 1, rats responded on concurrent-chains schedules with equalvariable-interval (VI) 10-s schedules in the initial links. Across conditions, fixed-interval schedules in theterminal links were varied to yield 1:1, 9:1, and 1:9 ratios of alcohol delivery. Initial-link response ratesreflected changes in terminal-link schedules, with greater relative responding in the rich terminal link.In Experiment 2, terminal-link schedules remained constant with a 9:1 ratio of alcohol delivery rateswhile the length of two equal duration initial-link schedules was varied. Preference for the rich terminallink was less extreme when initial links were longer (i.e., the initial-link effect), as has been previouslyreported with food reinforcers. This result suggests that the conditioned reinforcing value of an alcohol-associated stimulus depends on the temporal context in which it is embedded. The concurrent-chainsprocedure and quantitative models of concurrent chains performance may provide a useful frameworkwithin which to study how contextual variables modulate preference for drug-associated conditionedreinforcers.