Effects of d-amphetamine on choice in a rapid-acquisition concurrent-chains procedure

Abstract

Choice behaviour is an important topic for research in behavioural analysis and behavioural pharmacology. The matching law and generalized matching law have provided a good description for choice behavior in many studies. The purpose of the present study was to examine how d-amphetamin e affects sensitivity and rate of acquisition of pigeons’ choice between delayed reinforcers in the concurrent-chains procedure. Two experiments are reported, both used ‘rapid acquisition’ concurrent-chain schedules in which one terminal link was fixed-interval (FI) 8 s while the other terminal link changed across sessions between FI 4 s and FI 16 s according to a pseudo-random binary sequence (PRBS). In Experiment 1, the reinforcer magnitudes were constant and equal, but there were two types of trials in Experiment 2 in which magnitudes for both terminal links were either small or large. After baseline training, varied doses (e.g. 0.3, 1.0, 1.7 and 3.0 mg/kg) of d-amphetamine were administered prior to drug testing sessions. The results found that increasing doses of d-amphetamine reduced the sensitivity to the immediacy ratio in the current session, but no evidence that within- session acquisition was affected in Experiment 1, and no evidence that absolute magnitude affected preference or resistance to change in Experiment 2. Overall, these results show that d-amphetamine reduces sensitivity to delay, and that the rapid -acquisition concurrent-chains design can provide a useful procedure for testing drug effects on choice.