title: Anticipatory contrast and diet selection by pigeons.
abstract: The effect of future rate of reinforcement on choice and rate of responding was examined in three experiments in all of which pigeons performed on an operant simulation of diet selection followed by either a high or low rate of reinforcement. In Experiment 1 the duration of the prey selection task was 20 min. A within-subjects design was used: in one operant chamber a high rate of reinforcement followed the session of diet selection, and in another chamber, a low rate of reinforcement followed. In Experiment 2 a between-subjects design was used with 8 min of diet selection and a stronger manipulation of rate of reinforcement. In Experiment 3, a within-subjects design was used with more highly discriminable operant chambers. The results on rate of responding were consistent with what is known about contrast: A weak contrast effect during the diet selection task was obtained in Experiment 1, a larger contrast effect in Experiment 3, and a conditioning effect was found in Experiment 2. The effect on choice was examined in Experiments 1 and 3 but was weak in both cases. The results suggest that the mechanism underlying contrast in choice and rate of responding are not one and the same. Foraging implications are discussed.
authors.affiliation: University of Ottawa, Ottawa, Ont., Canada, K1N 6N5.
authors.forename: C M
authors.initials: CM
authors.lastname: Plowright
authors.forename: H
authors.initials: H
authors.lastname: Duggan
authors.forename: A
authors.initials: A
authors.lastname: Kruzynski