The brain's attentional system can only actively track a few items at once

Levitin explains that working memory, the mental workspace used for active thought and decision-making, has a famously limited capacity, generally able to hold only a handful of discrete items at any given moment before information starts falling away or getting confused. This constraint hasn't changed even as the volume of information modern life demands people track has exploded.

He argues that this mismatch, an ancient, narrow-capacity attentional system facing an unprecedented flood of emails, notifications, tasks, and decisions, is the root cause of much modern stress and error, not personal weakness or lack of discipline. People who feel chronically overwhelmed are often simply exceeding a hard biological limit rather than failing at effort or willpower.

Levitin uses this finding to argue that the solution isn't trying harder to remember or focus, but restructuring environments and tasks so that fewer things need to be held in active attention simultaneously, shifting cognitive burden onto external systems instead.

Takeaway: chronic overwhelm often reflects a biological attention limit being exceeded, not a personal failure to try harder.