Should I stay or should I go?: human studies of foraging for reward

Foraging behaviour is thought to be ubiquitous across the animal kingdom. Animals must typically integrate complex information to decide how long to exploit a ‘patch’ of resources before leaving to forage for other, more worthwhile, patches. Optimal Foraging Theory predicts how an animal should behave as a function of the travel time between patches, and the resources available within each patch. In humans, foraging theory has been applied in multiple domains – from information foraging accounts of selective attention, to value-based choices in executive function. In this research, I asked whether human foraging for reward adheres to the predictions of Optimal Foraging Theory developed in non-human animals. Participants in this task determined how long to remain in a patch of exponentially decreasing rewards (dwell time), based on a predetermined delay (travel time) prior to each patch. Across four experiments, I showed that: (1) individuals exploit resource-rich patches for longer periods of time when they follow greater versus shorter delays; (2) dwell times are based on the mean travel time of the environment, rather than patch-specific delays; and (3) dwell times are unaffected by the variance or (4) volatility of delays within each environment. Overall, these findings are consistent with the predictions of Optimal Foraging Theory, and indicate the generalisability of this theory to human decisions. This study paves the way for further research into the components of choice behaviour that may be pathologically altered in patients with disorders of motivated decision-making, such as Parkinson’s disease.