Effects of the relative values of alternatives on preference for free-choice in humans

Organisms often prefer conditions that allow selection among alternatives (free-choice) to conditions that do not (forced-choice), particularly when response alternatives in free-choice produce equal or greater reinforcer magnitudes than those available under forced-choice. We present data on free-choice preference for human participants who gained or lost points by selecting images of cards on a computer screen under a concurrent-chains schedule. Responding during the initial link gained access to a terminal link offering a single-card set (forced-choice) or a three-card set (free-choice). The alternatives in free-choice produced reinforcer magnitudes (points) that were: (a) equal to forced-choice; (b) equal to and greater than forced-choice; and (c) equal to and less than forced-choice. Participants showed reliable preference for free-choice under some conditions; however, preference decreased as reinforcer magnitude for some alternatives in free-choice was reduced. This occurred even though it was possible to obtain the same number of points across free- and forced-choice. Although preference for free-choice was clearly demonstrated, the effect of points available in the terminal link suggests that this phenomenon is subject to modulation by other processes, such as reinforcement or punishment by obtained outcomes in the terminal link. Context (reinforcer-gain or -loss) was not a reliable predictor of preference.