Changes in executive control across the life span: Examination of task-switching performance

A study was conducted to examine changes in executive control processes ove r the life span. More specifically, changes in processes responsible for pr eparation and interference control that underlie the ability to flexibly al ternate between two different tasks were examined. Individuals (N=152) rang ing in age from 7 to 82 years participated in the study. A U-shaped functio n was obtained for switch costs (i.e., the time required to switch between tasks compared with a repeated-task baseline), with larger costs found for young children and older adults. Switch costs were reduced with practice, p articularly for children. All age groups benefited from increased preparati on time, with larger benefits observed for children and older adults. Adult s benefited to a greater extent than children when the interval between the response to one task and the cue indicating which task to perform next was lengthened, which suggested faster decay of interference from the old task set for adults than for children. A series of hierarchical analyses indica ted that the age-related variance in task-switching performance is independ ent, at least in part, from the age-related variance in other cognitive pro cesses such as perceptual speed and working memory. The results are discuss ed in terms of the development and decline of executive control processes a cross the life span.