Marketers Hit Hardest by AI ‘Brain Fry

A recent study published in the Harvard Business Review has explored a form of mental fatigue the authors term “brain fry,” linked to heavy use of AI tools. Among the findings, marketing professionals appear to be the most affected, reporting the highest incidence of this cognitive strain.

The research, conducted by experts from Boston Consulting Group and the University of California, Riverside, surveyed 1,488 full-time workers in the United States. Overall, 14% of respondents reported experiencing “brain fry,” defined as mental exhaustion resulting from excessive interaction with or oversight of AI tools beyond an individual’s cognitive capacity. Among marketing staff, the rate was significantly higher at 26%, indicating that the role is particularly susceptible to AI-related mental strain.

Understanding Brain Fry

The study highlighted that the most mentally taxing AI activity was direct oversight. Workers whose roles required close monitoring of AI tools reported higher levels of fatigue and information overload compared to colleagues with fewer oversight responsibilities. High oversight demands were also linked to a 19% increase in perceived information burden.

Another major factor contributing to brain fry was the expansion of workload caused by AI. When AI tools increased the scope of tasks for employees, it extended what the researchers call the “sphere of accountability,” requiring individuals to manage more outcomes across multiple tools within the same timeframe.

Interestingly, the study found that there is a cognitive ceiling when it comes to AI tool usage. Workers reported productivity gains when using one to three AI tools, but these gains plateaued and even declined after three. This suggests that overextending AI usage can backfire, causing more fatigue than efficiency.

Who Is Most Affected

The survey revealed that it’s often the top performers—the “superstars” of organisations—who experience the highest cognitive strain. These early adopters and high achievers tend to use AI intensively, managing multiple platforms simultaneously, which can push their cognitive limits.

Marketing professionals topped the list with a 25% brain fry rate. HR and people operations followed at 19%, with operations and engineering tied at 17%. Finance and IT both reported 16%, while legal and compliance had the lowest levels at just 5%.

Workers described symptoms such as mental fog, slower decision-making, and a buzzing feeling in the head. Many said they needed to step away from their desks to reset their focus. One finance director explained the experience as overwhelming, noting that after repeated back-and-forths with AI, they could barely comprehend their own work and had to revisit it the next day.

The Business Impact

The cognitive strain of brain fry also carries tangible consequences for business performance. Employees experiencing it scored 33% higher on decision fatigue, 11% higher on minor errors, and 39% higher on major mistakes. Moreover, brain fry correlated with an increased likelihood of leaving a role: 34% of affected workers reported active intent to quit, compared to 25% of those without mental fatigue.

AI: Both a Help and a Challenge

The study distinguishes brain fry from burnout. While burnout reflects emotional exhaustion, brain fry is an acute cognitive overload from pushing attention and working memory to their limits. Using AI to automate repetitive tasks did reduce burnout by 15%, but it did not significantly alleviate mental fatigue.

Managerial and organisational support also influenced brain fry levels. Workers whose managers took time to address AI-related questions had 15% lower fatigue scores, while those who felt pressured to achieve more because of AI reported 12% higher fatigue. Organisations emphasising work-life balance saw a 28% reduction in employee mental strain.

Implications for Businesses

These findings provide a nuanced view of AI’s impact on the workforce. While AI may not be displacing jobs in marketing or other sectors, it can be contributing to fatigue among those using the tools most intensively. Teams juggling AI across content creation, analytics, and advertising should take note of the three-tool productivity ceiling and the high brain fry rates when structuring workloads.

The study’s authors advise limiting the number of AI tools each employee manages and avoiding adding excessive tasks, even if AI accelerates certain processes. They view their research as an early warning for organisations: while AI adoption can enhance efficiency, cognitive costs must also be considered.

Looking Ahead

Julie Bedard, a managing director and partner at BCG, emphasised in an interview that the study is not a reason to halt AI use, but a reminder to respect human cognitive limits. “The AI can run far ahead of us, but our brains are the same as yesterday,” she said. Organisations must balance AI adoption with employee well-being to ensure productivity gains do not come at the expense of mental health.