Why Multitasking Makes You Worse at Everything
Modern life celebrates multitasking—answering emails while on a call, cooking while scrolling, “catching up” on messages during meetings. We treat it like a badge of efficiency. Yet research across decades has shown the opposite: multitasking doesn’t make you more productive—it makes you worse at everything you’re doing. Psychologists call this task switching, not true multitasking, because the human brain can’t focus on two demanding tasks simultaneously. Every switch costs time, accuracy, and cognitive energy, even if it feels like progress.
The Brain’s Bottleneck
Neuroscientists at Stanford University led by Clifford Nass discovered that heavy multitaskers are actually less efficient than those who focus on one task at a time. In controlled tests, multitaskers struggled with filtering irrelevant information, switching attention, and organizing thoughts. Brain scans reveal why: the prefrontal cortex, responsible for decision-making and focus, can only process one complex task at once. When you toggle rapidly between tasks, your brain incurs a “switch cost”—a fraction-of-a-second lag that compounds into minutes or hours of lost productivity.
The Illusion of Efficiency
What makes multitasking addictive is dopamine. Each time you switch tasks, you experience a small chemical reward for novelty and completion. This creates a false sense of achievement—your brain feels busy and satisfied, even as your output quality declines. A study from the University of London found that people who multitasked during cognitive tests experienced IQ drops equivalent to someone who had stayed up all night. The decline was temporary but dramatic enough to mimic the effects of intoxication. Constant partial attention, it turns out, makes you mentally clumsy.
How It Affects Memory and Stress
Beyond performance, multitasking disrupts memory formation. The hippocampus, which encodes new information, struggles to store fragmented attention streams into coherent memories. That’s why you can scroll through social media while watching TV and recall neither afterward. Chronic multitasking also elevates cortisol, the stress hormone, because the brain perceives constant switching as mental overload. Over time, this creates fatigue, irritability, and decreased emotional regulation—a cognitive version of burnout.
