N-back Task

A working-memory paradigm in which participants view or hear a sequence of stimuli (letters, digits, positions) and, on each trial, respond when the current stimulus matches the one presented N steps earlier. Higher N levels place greater load on working memory and executive control, and the task is widely used in cognitive neuroscience and HCI as a standardised manipulation of cognitive load. In accessibility research it serves both as a cognitive stressor (for studying recovery interventions) and as a measure of how assistive interfaces or environmental factors tax working memory.