Choice Between Stimuli Associated with Different Histories of Reinforcement when Presented Separately

Abstract

<p> Four experiments are reported in which choice behavior was examined in the pigeon. An apparatus was used in which each of two adjacent keys could be lit with either a red or a green dot. In each experiment, subjects received trials of fixed length with one color at a time (single-stimulus training) before receiving trials with both keys lit together (choice test). On choice tests in Exp. 1, 2, and 3, birds pecked at a higher rate to the stimulus in which a higher number of reinforcements had been received per unit time with the stimulus present, but differences between stimuli in reinforcements per session did not reliably affect choice behavior and differences in proportion of trials followed by reinforcement had only weak effects. In Exp. 4, a brief daily choice test was used to evaluate recency effects. It was found that several sessions of experience with only one color were often necessary to reliably shift choice to that color.</p>