Your Attention Span Isn't Broken — It's Untrained. The Science of Rebuilding Focus

A veteran writing teacher recently handed his class a 20-page article, the same reading he’d assigned for years. This time nobody finished it. Not one student. The story showed up in a June 22 Inc. column by Jessica Stillman, and it names a worry a lot of us keep to ourselves: that our attention spans are quietly falling apart. The good news buried in the research is that focus isn’t a fixed trait you’re losing. It’s a capacity, and you can train it back.

What happened

The column leans on research into something economists call cognitive endurance: the ability to keep doing hard mental work over a long, uninterrupted stretch. The key paper, “Cognitive Endurance as Human Capital” by Christina Brown, Supreet Kaur, Geeta Kingdon, and Heather Schofield, treats sustained attention not as a personality quirk but as something practice builds.

To test it, the researchers ran a field experiment with 1,600 primary school students, randomly giving some of them more time on sustained mental work during the day. One group practiced with math problems. Another practiced with non-academic games, which was the clever part: it separated “thinking hard” from the subject matter itself.

Both worked. Kids who practiced sustained focus showed 22% less drop-off in performance over time on demanding tasks like listening comprehension and IQ tests, paid more attention in class, and did better at school overall. The games worked too. It was the act of effortful, continuous thinking that built the muscle, not the topic.

Why it matters

This flips the whole “my attention span is cooked” conversation. If focus were simply being destroyed by phones, the only move would be defensive: block, delete, abstain. The cognitive-endurance work points somewhere more hopeful and more demanding. Attention behaves like a trainable capacity, and you rebuild it by doing the reps your day stopped asking for.

Students who practiced sustained mental effort showed 22% less decline in performance over time, and even content-free focus practice worked. — Brown et al., “Cognitive Endurance as Human Capital”

Modern work mostly trains the opposite. A day of pings, quick reviews, and tab-switching is interval training for distraction: short bursts, constant switching, never a long climb. The endurance fades from disuse, the same way it would in your legs.

What this means for developers

Deep work is the job. Holding a system in your head long enough to actually reason about it is cognitive endurance by another name, and the research says you build it on purpose:

• Add load gradually. Don’t expect a four-hour flow state tomorrow. Start with a block you can finish, 25 minutes, then 45, then 90, and stretch it as you get stronger. The win is finishing, not heroics.
• Stay in the hard part. The moment a problem gets effortful is the moment you reach for Slack. That’s exactly the rep that counts, so pushing through the dip is the actual training.
• Cut the distraction reps. Batch your messages and reviews into windows instead of letting them run all day. Every context switch is practice for the wrong skill.
• Make focus blocks something you can see. “Finished a 90-minute deep-work block” is a trackable habit. Treat it like a training log: count the reps, grow the duration.

The bottom line

The 20-page reading nobody could finish isn’t proof that focus is gone for good. It’s proof it went untrained. The research is fairly clear that the capacity comes back when you practice sustained effort on purpose. For a developer that isn’t self-help, it’s maintenance on your main tool. Train deep work like training, add reps, and the focus you thought you lost grows back.