Break the split-screen: What happens to your brain when you multitask?

Male designer looking stressed while working on his computer in the office. [Courtesy/GettyImages]

We live in a world of endless tabs, tweets, reels, and series. Each scroll feels rewarding, but your brain quietly pays the price. 

Every time you switch between Instagram, email, and news updates, your brain releases a small hit of dopamine, tricking you into feeling productive. In reality, these distractions chip away at your focus and waste time. 

Experts agree that while multitasking may work with simple tasks, such as walking and chatting, it’s nearly impossible when handling two mentally demanding activities. What we call multitasking is often just rapid task switching.

This overloads the brain, leading to mistakes, slower thinking, and moments of confusion like, “What was I doing again…?” Here’s what actually happens to your brain when you multitask:

1. Stress levels go up

Each time you juggle tasks, cortisol (the stress hormone) spikes. The rush may feel productive in the moment, but experts say multitasking can quickly lead to mental overload, anxiety and exhaustion.

2. Grey matter takes a hit

A 2014 University of Sussex study used MRI scans to compare people who frequently used multiple devices at once with those who didn’t. Heavy multitaskers showed lower grey matter density in the anterior cingulate cortex, involved in emotion control and decision-making. Multitasking might not just mess with your mind, it could even reshape it.

3. Attention span decreases

Multitasking involves constant back-and-forth switching of attention. According to the American Psychological Association (APA), this switching delays the brain’s ability to re-focus, making people more distractible and weakening their attention span.

4. Productivity plummets

The APA also reports that task switching can waste up to 40 per cent of productive time. Other studies put that figure as high as 49 per cent, once you factor in mistakes, lost details and unfinished tasks.

5. IQ takes a dive

A study by the University of London found that multitasking led to IQ drops of up to 15 points in men, the equivalent of performing like an eight-year-old, and five points in women. 

6. Quality of work suffers

When juggling multiple information streams, the brain struggles to filter out distractions. A study published in the Proceedings of the National Academy of Sciences found that chronic media multitaskers had trouble organising thoughts and switching efficiently between tasks, even when offline.

To break the multitasking habit, try setting aside focused time blocks for single tasks. This reduces mental clutter and boosts productivity. Regular screen-free breaks also help reset the brain and ease fatigue. Mindfulness, such as deep breathing or focusing on one sound, sharpens attention. Turn off notifications and limit email or social media checks to avoid distractions.