The question assumes focus is a muscle you train. The strongest evidence says the training barely carries over, and the real gain comes from subtraction — starting with the thief you cannot feel.
The question carries an assumption inside it: that concentration is a muscle, and that training makes it bigger. The strongest evidence says close to the opposite. What can be trained barely carries over to anything else, and the real improvement comes from subtraction — where the largest thief turns out to be exactly the one you cannot feel.
In 2016 seven researchers went back through the whole literature on commercial brain-training programmes. The conclusion was short: people get better at the exact task they trained on, sometimes at a task closely resembling it, and there is almost no evidence of improvement in everyday cognition. A separate meta-analysis of working-memory training came out the same way.
This is worth saying because it is the one part of the concentration question that has been packaged and sold — and it is the thinnest part of the evidence. Anyone selling you an exercise to train your focus is selling exactly that thin part.
Van Dongen and colleagues put 48 healthy adults on 4, 6 or 8 hours of sleep a night for fourteen consecutive nights, testing them daily. The six-hour group slid steadily across the whole fortnight with no sign of bottoming out, ending up impaired to roughly the degree of one or two nights without sleep at all.
But the part that matters most is elsewhere: their own ratings of sleepiness rose at first and then levelled off, while the measured performance kept falling. Which means I feel fine is not a measurement. It is the first thing to break.
In 2017 a famous study had people take the same test with their phone on the desk, in a bag, or in another room. The closer the phone, the worse they did — even when it was switched off and face down. The finding travelled everywhere.
But the rest has to be told. A pre-registered replication failed to find the effect. Then a synthesis of 56 studies covering more than seven thousand people found the overall effect indistinguishable from zero, with only working memory retaining something very small. The claim that merely having the phone there hurts you has not held up.
What nobody disputes is the checking itself. And that is the part you hold: not where the device is lying, but whether it is allowed to call you.
The number usually quoted is twenty-three minutes to get back to the original task. It is everywhere online and remarkably hard to trace to any published result, so it is better dropped in favour of what actually made it into print.
Mark, Gudith and Klocke measured people who were interrupted mid-task and found something surprising: they finished faster, with no loss of quality. The price sat elsewhere — more stress, more frustration, more felt time pressure, more effort. Interruption does not take away today's output. It takes away tomorrow's tolerance.
Leroy identified something finer still: switching tasks leaves residue. Part of your attention stays with the old task even after you have sat down to the new one. And there is a counterintuitive detail inside that: finishing the old task is not by itself enough to let go of it — what helps you let go is having been under time pressure as you finished.
Killingsworth and Gilbert asked around 2,250 adults, at random moments through the day, where their minds were. The answer: somewhere other than the task 46.9% of the time. That is the human baseline, not a condition to be cured.
So the right question is not how to have more attention, but what decides where it flows. Material that is too easy will not hold a reader; material that is too hard gets abandoned halfway; and material with no visible use goes the same way.
Which means calibrating difficulty and making the next action concrete is an intervention on attention, even though it sounds like an intervention on motivation.
Exercise and caffeine both give small, repeatable gains in alertness. Meditation may help, but when it is compared against a control group that also did something worthwhile, the effect shrinks considerably — in 2018 a critical review said plainly that this field had been oversold.
Ordered by the weight of the evidence, it goes like this. Sleep first, because it is the largest and because you cannot feel it. Then build a block of time nobody may enter — the painting above is an entire wooden room constructed inside a cathedral to do precisely that one job. Then take away the device's permission to call you. Then adjust the difficulty of whatever you are studying.
And stop measuring by feel. What is worth counting is how many times you were pulled out of the work in one session, and how many minutes the longest unbroken block lasted. Those two numbers can move within a week. Concentration in general is not a thing that moves.
The same article, told in plain words — for younger readers, or for anyone who wants the point quickly.
The question hides an assumption: that concentration is a muscle, and that exercising it makes it bigger. The best evidence says almost the opposite. What you can train hardly carries over to anything else, and the real improvement comes from taking things away.
Start with what does not work. In 2016 seven researchers read through everything published on commercial brain-training programmes. People do get better at the exact game they practised, and sometimes at a very similar game. Evidence that their everyday thinking improved was almost absent. A separate review of working-memory training landed in the same place.
That matters, because brain training is the only part of this whole subject that gets sold to you — and it is the part with the least behind it.
Now the biggest thief. Van Dongen and colleagues had 48 healthy adults sleep four, six or eight hours a night for fourteen nights in a row, testing them every day. The six-hour group got steadily worse across the entire two weeks, with no sign of stopping, and by the end were as impaired as someone who had stayed up all night once or twice.
Here is the part that should worry you. The volunteers rated their own sleepiness each day. Those ratings rose at first and then flattened out — while the measured performance kept sliding. So I feel fine is not a measurement. It is the first instrument to break.
Next, the phone — and this story has to be told to the end. In 2017 a famous experiment had people take the same test with the phone on the desk, in a bag, or in another room. The nearer the phone, the worse they scored, even when it was switched off and face down. The result travelled everywhere.
But then a careful repeat of the study, registered in advance, found nothing. And a review pooling 56 studies of more than seven thousand people found the overall effect impossible to tell apart from zero, with only working memory keeping a very small trace. The claim that a phone merely lying there damages you has not held up.
What nobody argues about is looking at it. And that is the part you control: not where the phone is, but whether it is allowed to call you.
Then there is interruption. You will often see a figure of twenty-three minutes to get back to what you were doing. It is all over the internet and very hard to trace to any published study, so it is better to use what actually got printed.
Mark, Gudith and Klocke watched people who were interrupted mid-task, and the result was strange: they finished faster, and the quality was no worse. The cost showed up somewhere else — more stress, more frustration, more feeling of being rushed, more effort spent. Interruption does not steal today's work. It steals tomorrow's patience.
Leroy found something finer still. When you switch tasks a residue stays behind: part of your attention is still on the old job while you sit at the new one. And oddly, finishing the old job is not by itself enough to release you. What releases you is having been under time pressure while finishing it.
It helps to know the baseline, too. Killingsworth and Gilbert asked about 2,250 adults, at random moments, where their minds were. Minds were somewhere else 46.9% of the time. That is ordinary human life, not an illness.
So the useful question is not how to have more attention, but what decides where it goes. Material that is too easy will not hold you. Material that is too hard gets dropped halfway. Material with no visible purpose goes the same way. Setting the difficulty right is an attention tool, even though it sounds like a motivation tool.
A few smaller things are real. Exercise and caffeine both give modest, repeatable gains in alertness. Meditation may help, but when it is measured against a control group that was also doing something worthwhile the effect gets much smaller — a critical review in 2018 said openly that this field had been oversold.
So, ordered by how much evidence stands behind each: sleep first, because it is the biggest and because you cannot feel it. Then a block of time nobody is allowed into. Then taking away the phone's permission to call you. Then adjusting the difficulty of what you are studying.
And stop judging by feel. Count two things instead: how many times you got pulled out of the work in one sitting, and how many minutes your longest unbroken stretch lasted. Those two numbers can change within a week. Concentration in general is not the kind of thing that changes.
These articles summarize well-established research in learning science and linguistics. Key sources and further reading:
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