The sources

When Using AI Leads to “Brain Fry

Bedard, Julie, et al · Harvard Business Review / BCG · March 2026

1,488 US workers; 39 percent higher major errors; 33 percent more decision fatigue; productivity peaks at three simultaneous AI tools.

Cited in

Bedard, Julie, et al. 'When Using AI Leads to "Brain Fry".' Harvard Business Review / BCG, March 2026. (1,488 US workers; 39 percent higher major errors; 33 percent more decision fatigue; productivity peaks at three simultaneous AI tools.)