Role of aging and working memory in performance on a naturalistic visual search task.

Studying age-related changes in working memory (WM) and visual search can provide insights into mechanisms of visuospatial attention. In visual search, WM is used to remember previously inspected objects/locations and to maintain a mental representation of the target to guide the search. We sought to extend this work, using aging as a case of reduced WM capacity. The present study tested whether various domains of WM would predict visual search performance in both young (n = 47; aged 18-35 yrs) and older (n = 48; aged 55-78) adults. Participants completed executive and domain-specific WM measures, and a naturalistic visual search task with (single) feature and triple-conjunction (three-feature) search conditions. We also varied the WM load requirements of the search task by manipulating whether a reference picture of the target (i.e., target template) was displayed during the search, or whether participants needed to search from memory. In both age groups, participants with better visuospatial executive WM were faster to locate complex search targets. Working memory storage capacity predicted search performance regardless of target complexity; however, visuospatial storage capacity was more predictive for young adults, whereas verbal storage capacity was more predictive for older adults. Displaying a target template during search diminished the involvement of WM in search performance, but this effect was primarily observed in young adults. Age-specific interactions between WM and visual search abilities are discussed in the context of mechanisms of visuospatial attention and how they may vary across the lifespan.