Effects of Reinforcement Duration and Duration-correlated Stimuli on Preference in Pigeons

Abstract

Pigeons were trained in a two-key, concurrent chains choice procedure with equal initial and terminal links. Across conditions, the durations of reinforcement in the terminal links were either equal (3-s vs 3-s) or unequal (3-s vs 6-s), and these durations were either uncued by hopper lights (both white) or cued (3-s: white; 6-s: colored). The pigeons’ choice responding leading to the longer duration of reinforcement was generally in the range of indifference with nondifferential hopper lights, but favored the longer duration with differential hopper lights. Taken together, the data suggest that differential hopper lights facilitated the discrimination of the longer reinforcement duration, and hence enhanced its control.