Ageing is associated with exaggerated overstaying in foraging behaviour.

People constantly decide how much time to invest in rewarding activities. Foraging tasks assess this decision-making by measuring when individuals switch between contexts. People typically perform suboptimally in these tasks, largely due to overstaying, but it remains unclear whether this tendency changes with age independently of cognitive abilities and mental health factors. Previous research showing increased sensitivity to the opportunity cost of time in older adults predicts less overstaying, whereas a hypothesised shift towards exploitative behaviour predicts more overstaying. In an online foraging task, 350 young and older adults decided when to switch between contexts with varying reward conditions. We also assessed cognitive performance and self-reported motivation and depression. Participants consistently overstayed, and this behaviour was strongly associated with sensitivity to reward changes. Despite this, older adults selectively overstayed more without increased reward-based adaptation. Our findings show ageing is associated with exaggerated overstaying, supporting increased exploitative behaviour in old age.