The n-Back test is presumed to measure executive control of the updating of information in working memory. (Shimamura, 2000) Watter, Geffen and Geffen (2001) based on their work with the P300 event-related-potential have suggested that the n-Back is a dual task in that latencies of the P300 did not change with increasing task difficulty, that is memory load while amplitude did reflecting in their view a "reallocation of attention and processing capacity away from the matching subtask."

The n-Back task is one in which the participant is presented a series of stimuli at a constant rate. The task of the participant is to determine if the currently presented stimulus is similar (along some dimension) to one they have recently (usually one, two or three positions back) seen in the stream. Match criteria can be dimensions like material, position on the screen, color or some combination. CATs n-Back allows for substantial control over the position in which the material is presented (nine different positions), the nature of the material (any character or "dingbat" string, and any color. The experimenter can set the speed at which the sequence is presented including both the stimulus on time and the inter-stimulus interval. Participant responses can be made either using the keyboard or the mouse.

At this time no normative data is available for this test.