Recent experience-driven behaviour optimizes foraging

Owing to the trade-off between time for searching for and exploiting resources, choosing a profitable food resource is key for an animal's survival and reproductive success. Although the optimal diet model (ODM) from optimal foraging theory (OFT) has demonstrated this point successfully by modelling the global maximization of energy intake rate for foraging, the behavioural mechanisms by which animals achieve optimization, especially when facing a novel environment, have yet to be understood. Here we propose a recent experience-driven (RED) decision-making rule of foraging that relies only on short-term memory of recent feeding experience and hunger aversion. This contrasts with the ODM, which assumes both global information access to the forager and its apparent ability to reach optimal choices. Despite relying only on limited past experience and hunger aversion, this behavioural rule not only accounts for nearly the same energy intake rate as predicted by the ODM but also can flexibly respond to changing environments by rapidly reaching new optimization. The RED behaviour also predicts a more realistic partial preference for diet choice, contrasting with the zero-one rule of OFT which allows for no partial preference within the forager's diet. The partial preference simply emerges from the RED strategy, as opposed to decision-making errors imposed from behavioural and physiological constraints. The RED rule further elucidates three potential traits that natural selection can act upon for optimizing foraging: (1) short-term memory of recent feeding experience, (2) ability to recognize encountered resources, and (3) basic neural set-up for alternative responses to environmental cues. This simple and flexible RED rule thus provides a behavioural mechanism for optimal foraging, and can be further applied to decision-making theory in psychology and economics.