The repetition detection task requires participants to find a repeated stimulus (number, letter, or location) in a series. Working memory is needed to successfully complete the task, as it is necessary to use memory storage (remember previous items) and processing (compare items for identification of a repeat). The task is often completed where the participant controls how quickly the items are presented (by pressing the spacebar). This allows the measurement of processing time as well as accuracy of finding the repeat. The task can be manipulated in many ways to create new and interesting conditions to compare working memory performance in younger and older adults.

• Switching the focus of attention:  The Repetition Detection task is modified so that participants must find a repeat in one, two or three locations of the computer screen at the same time. In order to do so the participant must switch where and what information they are attending to. A real-life example of focus switching is driving. In order to drive a car you need to switch your attention between multiple views (front windshield, rear view mirror, side mirrors, someone sitting next to you, the radio, etc). Switching is a component in many working memory tasks. The study examines if this is one source of age-related differences in working memory (see Figure 1 below for previous findings).

• Examination of strategies: Each individual uses different strategies to complete the Repetition Detection task. This study provided specific strategies (to go fast, slow, say items out-loud, or point to items) while completing the task. It is of interest if certain strategies work best for younger adults while others work best for older adults (see Figure 2 below).

• Stimuli similarity: One of the reported difficulties of completing the Repetition Detection task in multiple locations at the same time is the confusion of stimuli. Therefore, the current study modifies the "switching the focus of attention" study by presenting different types of stimuli in each location.

• Working memory training: Older adults with and without a diagnosis of Alzheimer's disease practice the Repetition Detection task over the course of 5-7 days. Over time the difficulty of the task is increased by manipulating the number of items in the series.

Figure 1. The data below represent 24 younger adults (average of 19.2 years old) and 26 older adults (average of 69.1 years old). The graph represents how accurately participants performed the verbal (numbers) and visuo-spatial (locations in a grid) Repetition-Detection task. In general, older adults were less accurate compared to younger adults, but, completing the task in two locations was not any more difficult for older adults than younger adults (both groups decline by approximately 43%). This suggests that there is not a specific age-related problem with focus switching.