Intact exploration in old age

Optimal foraging depends on a dynamic balance between exploration and exploitation, and the literature is in discord on whether our ability to forage optimally diminishes with age, with a bias away from exploration and towards exploitation. In this study, we used a virtual foraging experiment to test elderly participants and compared their heuristics for timing patch-leaving with those of young adults. The initial patch quality (reward probability) varied randomly, and the remaining reward probability in the current patch decreased exponentially, simulating a rapidly depleting resource to encourage exploration of new patches. The results showed a significant age effect on overall task performance, with the elderly exhibiting longer trial durations and lower total earnings. Replicating previous findings, the elderly demonstrated increased giving-up times compared to young adults, indicating a reduced propensity for behavioral exploration. However, when adjusting for the overall lower average collection rates in the elderly, both age groups timed their patch-leaving optimally according to the marginal value theorem, leaving a ‘patch’ when the current reward collection rate matched the average collection rate. These results suggest that despite age-related slowing in performance, the heuristics underlying optimal foraging behavior remain intact in older age.