Effects of target value and prevalence on foraging in aging

How do the value and prevalence of targets and the personality of the observer shape visual behavior in younger and older adults? In our hybrid foraging task, younger (18-35 years) and older (65-82 years) observers held four different targets objects in memory. They collected multiple instances of those targets from visual displays containing 60-105 moving objects (20-30% targets). Targets were worth points. Observers were asked to reach a point goal as quickly as possible. In three blocks, the point-value and the prevalence of each target type was independently manipulated. Results: Target-value and prevalence shaped behavior. Replicating prior results, observers favored more rewarding and more common items. While the effect of prevalence was highly consistent across observers, individuals varied in the effects of target value; especially when high value items had low prevalence and low value items were common. This condition mimics some real-world situations, e,g, where you prefer the low prevalence cashews in the trail mix, while the cheap raisins and peanuts are more common. In younger adults, personality measures related to reward-seeking behaviour predicted individual selection preferences. Lower reward-seeking was associated with a preference to pick frequent low-value targets over rare high-value items. Second, contrary to our predictions, we did not find age differences in the responsiveness to target value and prevalence. The effects were strikingly similar across age groups. This finding argues against genuine age-differences in the processing of reward-values. Rather, our results support consistency in the impact of reward on visual processing across the adult lifespan, as long as both younger and older adults can meet the learning requirements of the task.