Abstract
In nature, amount of work an animal must do to obtain a resource like water depends on conditions in the environment. Conditions change, so it would behoove animals to allocate effort flexibly such that they work enough, but not more than necessary. To study this, we maintained rats in an environment where all water was earned in a task. We varied the reward magnitude and measured voluntary effort and water consumption. The rats did more trials per day when the reward per trial was smaller, yet worked for more water per day when rewards were larger. We propose an analytic model based on utility maximization which can account for these behavioral observations. The model is fit with per-day total work and consumption, but provides insight into the timing of trials and implicates a candidate neural substrate.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Revised throughout, no substantial change in results or conclusions.