Attention Decline in Knowledge Workers
Overview
Gloria Mark and colleagues at UC Irvine tracked focused task time in knowledge workers for over two decades. The decline began before AI — driven by the internet and smartphones — and is steep.
The Data
| Year | Average focused time on one screen |
|---|---|
| 2004 | ~2.5 minutes |
| 2012 | ~75 seconds |
| 2016–2020 | ~47 seconds |
Source: Mark, Attention Span (2023).
Two-thirds of sustained attention lost in twenty years.
Attention Residue
Duration is only part of the problem. Each time attention switches, there is a recovery cost — what researchers call attention residue (Rubinstein, Meyer & Evans, 2001). Task-switching produces lost time, increased errors, and shallower thinking. Every switch taxes the quality of whatever comes next.
Why It Matters for AI
AI raises the demand for sustained attention (more inputs to review, more outputs to evaluate, more context to weigh) at the exact moment the underlying capability is declining. This creates a growing gap between what is required and what the workforce can deliver.