Sophie Leroy, a researcher at the University of Minnesota, ran an experiment in 2009 that explains why you feel like you get nothing done despite working all day. She gave participants Task A, interrupted them mid-way through, and moved them to Task B. The result? Even when people fully switched to the new task, part of their attention stayed stuck on the previous one. Leroy calls this attention residue. The more you jump between tasks throughout the day, the more residue accumulates. By the end of the day, you are working with a brain split across dozens of unfinished loops.
This is not a problem of lazy people. It is a problem of environments that force us to respond to emails, Slack messages, notifications, and "quick questions" from colleagues in real time. Cal Newport, a computer science professor at Georgetown University, named the solution in his 2016 book: deep work.
What Is Deep Work and Why Does It Matter
Newport defines deep work as professional activity performed in a state of full concentration that pushes your cognitive abilities to their limit. Think writing code, analyzing data, strategic planning, creative writing. Work that is hard to replicate and creates real value.
The opposite is shallow work. Emails, admin, routine meetings, filling out spreadsheets. Things that need to get done, but that anyone could handle after a brief orientation. Newport argues that most people spend over 60% of their workday on shallow work, leaving only fragments between meetings for the stuff that actually matters.
Why is this a problem? Because the ability to do deep work is becoming increasingly rare in a world full of distractions, and at the same time increasingly valuable in an economy that rewards specialized knowledge and creative problem-solving. If you can regularly sink into deep work for two to three hours a day, you hold an enormous advantage over people who spend their entire day reacting to stimuli.
Why Multitasking Does Not Work
Back to attention residue. Leroy found that residue is strongest when the previous task was not completed and you have no plan for when you will return to it. In other words: when a colleague interrupts you mid-analysis and you have no idea when you will get back to it, part of your brain stays on that analysis whether you want it to or not.
Here is the counterintuitive part. Multitasking feels productive. You get the sense that you are handling more things at once. But research consistently shows the opposite. A Stanford study by Ophir, Nass, and Wagner (2009) compared habitual multitaskers with people who focus on one thing at a time. The multitaskers were worse at filtering out irrelevant information, slower at switching between tasks, and had poorer working memory. They were weakest at precisely the things they believed they excelled at.
Your brain simply cannot process two demanding cognitive tasks at the same time. What we call multitasking is actually rapid switching. And every switch costs time, energy, and a slice of mental capacity you never get back.
Four Strategies for Deep Work
In his book, Newport describes four approaches to incorporating deep work into your life. None of them is universally best. It depends on your job, your personality, and your circumstances.
The Monastic Strategy
Radical elimination of shallow work. Donald Knuth, the legendary Stanford computer scientist, does not use email. At all. Knuth explains on his website that email is a great tool for people whose work requires staying in touch with the world. His work requires the exact opposite. This approach is realistic only for people whose value lies entirely in deep work and who can afford to ignore almost everything else. Most of us cannot.
The Bimodal Strategy
Alternating between periods of total immersion and periods of normal operation. Carl Jung built a tower in Bollingen, Switzerland, where he regularly retreated for several days to write and think. The rest of the time he operated normally: seeing patients, lecturing, answering correspondence. This mode requires the ability to disappear for a day or more, which is doable for academics or entrepreneurs but difficult for people in corporate roles.
The Rhythmic Strategy
A regular daily block of deep work at the same time every day. From 6:00 to 8:30 every morning, you write, code, or analyze. Then you switch to normal mode. For most people, this is the most practical approach because it requires no special conditions. Just a calendar and discipline. The key is that the deep work block must be non-negotiable. The moment you sacrifice it for a meeting, the entire system starts to crumble.
The Journalistic Strategy
Switching into deep work whenever an opportunity appears: a free hour between meetings, a cancelled lunch, a quiet morning at the office. Newport named this after journalists who have to write articles in the middle of newsroom chaos. But he warns: this method only works for people who have already trained the ability to dive deep quickly. If you are new to deep work, you need ritual and regularity, not flexibility.
How Personality Affects Your Focus
Not everyone drops into deep work with equal ease. And the reasons are not just about habits. They also connect to your personality type.
Start with the most visible factor: introversion versus extraversion. Introverts have a natural advantage in environments that require silence and solitude. Hans Eysenck showed back in the 1960s that introverts have a higher baseline level of cortical arousal, meaning they need less external stimulation to feel "engaged." Long stretches of quiet work are not torture for them; they are a natural state. Extraverts have it harder. They need stimulation, and when there is not enough, they go looking for it: they pull out their phone, message a colleague, grab a coffee. This does not mean extraverts cannot do deep work. But they need different conditions: perhaps working in a coffee shop instead of a silent office, or taking short social breaks between focus blocks.
The difference along the sensing versus intuition axis is interesting too. Sensing types prefer concrete, structured tasks with clear steps. Deep work comes easily to them when they know exactly what to do: fine-tuning a budget, reviewing code, writing a report from a template. Intuitive types, on the other hand, need room for abstract thinking and connecting seemingly unrelated dots. Their deep work looks different: brainstorming, strategic planning, writing. But intuitive types also have a stronger tendency to drift from a task toward the next interesting idea, so they often need tighter external structure.
If you are not sure where you fall on these dimensions, a work style test can help. It shows you what kind of environment and conditions bring out your best work.
How to Build Your Deep Work Ability
Deep work is a skill, not an innate talent. And like any skill, it can be trained. Newport compares the ability to focus to a muscle: if you do not use it, it weakens. If you train it regularly, it grows stronger.
Here is the problem. Most people actively weaken their "focus muscle." Every moment of boredom filled by reaching for your phone, every reflexive check of social media, every glance at your inbox "just in case" teaches your brain that it is okay to redirect attention whenever the impulse strikes. And then you wonder why you cannot sit with one task for 90 minutes.
Training starts small. Tomorrow, try giving yourself 45 minutes of uninterrupted work on a single task. Phone on airplane mode. Email closed. Slack off. If you feel the urge to check notifications after 20 minutes, notice the impulse and return to your work. Next week, add 15 minutes. Within a month, you will be able to work for 90 minutes straight, and you will be surprised by how much you accomplish in that time.
Digital Detox at Work: What Actually Helps
The digital detox concept is often presented as a phone-free weekend in a cabin in the woods. That is fine, but it only treats the symptom. The real problem is the eight hours at work where everything from Slack to the colleague who stops by "for just a second" pulls your attention apart.
A few approaches that hold up in practice:
- Batch processing communication. Instead of monitoring email and chat continuously, set two or three windows per day when you process messages all at once. Say 9:00, 13:00, and 16:30. The rest of the day, your communication channels stay closed. Tim Ferriss popularized this method in The 4-Hour Workweek, and plenty of people have discovered that the world does not collapse when you do not reply within five minutes.
- Signal your unavailability. Put on headphones (even without music), set a "deep work" status on Slack, or agree on a visual signal with your team. A study by Perlow and Porter published in Harvard Business Review (2009) found that teams that introduced regular "quiet hours" saw gains in both productivity and satisfaction.
- Separate your tools. If you can, use a different browser or browser profile for deep work than for communication. Your brain associates environments with types of activity. When you open a browser where the first tab is Gmail and the second is Slack, you naturally slide toward communication.
- The two-minute rule in reverse. If something pops into your head that needs doing and would take less than two minutes, do not do it right away. Write it down and return to your deep work. Those two minutes actually cost far more once you add the time to switch context and find your way back.
- Scheduled boredom. This is a Newport recommendation that sounds odd but works. Occasionally, just stand in line, wait for the bus, or sit in a waiting room without your phone. Let yourself be bored. Your brain needs to get used to the idea that not every pause must be filled with stimulation. Otherwise, you will never build the ability to stay with a task when it becomes briefly tedious.
When Deep Work Is Not the Answer
It would be easy to turn deep work into yet another productivity cult. But Newport himself admits that some professions derive their core value from shallow work. A manager whose main contribution is coordinating a team and responding quickly to problems cannot vanish into a quiet room for three hours. A salesperson needs to be available for clients. An executive assistant cannot close their inbox.
It is also true that not all valuable work requires deep concentration. Sometimes a group brainstorm produces more than three hours of solitary thinking. Sometimes a quick phone call solves a problem you would otherwise spend an entire day analyzing.
The point of deep work is not to eliminate all communication and collaboration. It is a tool for protecting the most valuable thing you have: your ability to think. Even one hour a day of truly focused work can produce more than an entire day of reactive task-hopping. And that is a goal within reach for nearly everyone.