The limits of attention for visual perception and action in aging.

This study aimed to investigate whether aging results in an increased attentional blink effect in older adults as compared to young adults. A rapid serial visual presentation (RSVP) paradigm was employed in which participants were asked to identify two targets (dual-task condition) presented in rapid succession. These targets were separated by various intervals in a stream of stimuli. The performance for identifying the second target was normally diminished as compared to identification of a single-task target. Various combinations of tasks, such as two perceptual tasks or one perceptual and one action task, as well as different types of pointing action, such as pointing to a displaced target, pointing to a stationary target or pointing to a disappeared target, were manipulated in this study to see if aging may further impact these variables. The results of this study showed that in young adults, successful identification of the first target interfered with identifying the second target, as well as the initiation time (action planning) of pointing to the second target. However, identification of the first target did not interfere with pointing movement time and pointing accuracy, even when the target was displaced, which required online control of action. Conversely, for older adults, successful central identification not only interfered with identifying the second target and with the pointing initiation time, but also interfered with pointing movement time for a displaced target. This suggests that older adults seem to be unable to concurrently identify the first target and correct their already-initiated pointing movement compared to young adults.