PERSON

Gloria Mark

The UC Irvine informatics scientist who spent two decades with a stopwatch measuring how knowledge workers actually spend their attention—and whose finding that the average focus interval has shrunk to forty-seven seconds became the empirical conscience of the AI productivity debate.

Gloria Mark did not theorize about distraction. She measured it. Beginning in the early 2000s, her research team at the University of California, Irvine, embedded observers in actual workplaces, logging every task switch, timing every engagement, and building a portrait of the modern knowledge worker’s day that bore almost no resemblance to the day the workers believed they were having. What emerged was the foundational dataset of the attention economy debate: the average worker switches tasks approximately every three minutes and forty seconds, and about half of all switches are self-initiated. The most recent measurements have driven the interval down to forty-seven seconds. Each switch leaves a trace of attention residue—a portion of cognitive capacity that remains allocated to the previous task, contaminating performance on the next. Accumulated across a day of hundreds of switches, the residue degrades executive function precisely in the domain that knowledge workers value most: the judgment, planning, and complex reasoning

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