A BCG study of US-based workers found that intensive oversight of AI agents can cause cognitive exhaustion that the researchers call “AI brain fry.” The researchers shared their results in Harvard Business Review:
Participants described a “buzzing” feeling or a mental fog with difficulty focusing, slower decision-making, and headaches. This AI-associated mental strain carries significant costs in the form of increased employee errors, decision fatigue, and intention to quit. … Many participants used the words “fog” or “buzzing.” They described intensive back-and-forth with the tools, followed by an inability to think clearly, like a mental hangover, comprised of difficulty focusing, slower decision-making, and headaches, requiring several to physically step away from their computer to “reset.”
The researchers found that brain fry is linked closely to the amount of oversight and direct monitoring the agents required: a high rather than low degree of oversight caused 14% more mental effort on the job, predicted 12% more mental fatigue, and predicted 19% greater information overload.
So even as productivity increases with agents churning out work, the personal cost of monitoring that work is high. The study found increased fatigue when the use of AI increases workload—producing more simply costs more—and also when users multitask across tools. “As employees go from using one AI tool to two simultaneously, they experience a significant increase in productivity. As they incorporate a third tool, productivity again increases, but at a lower rate. After three tools, though, productivity scores dipped.”
A senior engineering manager in the study described the effect this way: “It was like I had a dozen browser tabs open in my head, all fighting for attention. I caught myself rereading the same stuff, second-guessing way more than usual, and getting weirdly impatient. My thinking wasn’t broken, just noisy—like mental static. What finally snapped me out of it was realizing I was working harder to manage the tools than to actually solve the problem.”
But the kind of task matters. When AI was used to replace routine or repetitive tasks—what the researchers call toil—burnout scores were 15% lower than for those who didn’t use AI that way . The researchers were careful to delineate the difference between burnout (emotional fatigue) and brain fry (mental fatigue). Using AI for unpleasant tasks still caused mental fatigue, but improved emotional state: higher work engagement, more positive associations with AI, and more social connection with colleagues.
As a designer of intelligent interfaces, my takeaway is that people need help managing the overload of extremely productive but not entirely reliable agents. This help might be delivered through a mix of improved experience, tools, and processes that make oversight less effortful—or alternatively that help people regulate and reduce how much they engage in the first place.
“Just as we have norms for spans of control for managing humans, so, too, limits need to be defined for human + agent oversight and for agents alone,” the researchers wrote. “Tools that require less intense attention or working memory, which instead support creative mind wandering, foster social engagement, or scaffold skill development can produce even more business value but sustainably, while encouraging innovation, fostering growth, and sparking joy for users.”
That sounds like a design challenge.
