Using AI tools at work may boost efficiency, but new research suggests that overuse can lead to mental exhaustion. A study published by Harvard Business Review highlights a phenomenon called “brain fry,” describing cognitive fatigue linked to managing multiple AI tools.
The research, conducted by Boston Consulting Group and University of California, Riverside, surveyed 1,488 full-time employees across industries in the United States.
More tools, more fatigue
The findings show that workers who oversee multiple AI systems experience:
- Increased mental effort
- Higher levels of fatigue
- Greater information overload
The issue isn’t just using AI—it’s managing several tools at once, which creates constant oversight demands.
Productivity drops after a point
According to the study, productivity begins to decline when employees use four or more AI tools simultaneously. At that stage, decision fatigue and cognitive strain start to outweigh efficiency gains.
Researchers describe “brain fry” as a state similar to a mental hangover, including:
- Difficulty focusing
- Slower decision-making
- Headaches and stress
AI still helps—when used wisely
Despite these drawbacks, the study emphasizes that AI can reduce burnout when applied to routine or repetitive tasks. The key issue is balance: using AI as a helper, not as a system that requires constant supervision.
As AI becomes more embedded in daily workflows, the challenge for workers and organizations alike will be finding the right balance between automation and cognitive load.
