Quantity versus quality: Convergent findings in effort-based choice tasks.

Organisms must frequently make cost-benefit decisions based on time, risk, and effort in choosing rewards to pursue. Various tasks have been developed to assess effort-based choice in rats, and experimenters have found largely similar results across tasks and brain regions. In this review, we focus primarily on the convergence of different effort-based choice tasks where quality or quantity of reward are manipulated. In the former, the rat is typically presented with the option to work for a preferred reward or select a less preferred, but freely-available reward. In such paradigms, the rewards are of different identities but are confirmed to differ qualitatively in value by a food preference task when both are freely-available. In the latter task type, rats are required to select between higher magnitude versus lower magnitudes of the same reward, but each with a similar effort requirement. We discuss the strengths/limitations of these paradigms, and describe brain regions that have been probed that result in converging or equivocal findings. Results are also reviewed with reference to a need for future work, and the broader impacts and implications of studies probing the mechanisms of effort.