Choice behaviour of pigeons: effect of variation in amount and delay of reinforcement in presence and absence of discriminative stimuli

Abstract

Pigeons were offered a choice between two durations of reinforcement, one delayed 6 sec longer than the other. Within each session choice was made immediately, 2.5 sec, or 10 sec prior to delivery of the earlier reinforcer. The two reinforcer durations were varied over conditions that had either blackout (no cue) or discriminative stimuli (cue) in the delays. Preference for the larger more delayed reinforcer increased with increased delay until reinforcement. Preference was lower in the no cue conditions than in the corresponding cue conditions. The finding that sensitivity of initial link response ratios to ratios of amount and delay deviated from 1.0, has implications for the use of the matching law in studies that vary these reinforcer parameters. The generalised matching law which assumes such deviation gave a good account of the present data.