For years, screen time has been treated as the main culprit behind stress caused by smartphones. But new research suggests that we’ve been worrying about the wrong metric.

A study from Aalto University found that frequent, fragmented phone use is the primary driver of information overload and not total screen time.

So it’s not the hours that matter most, it’s how often you interrupt yourself.

What’s the problem with checking your phone?

The study tracked nearly 300 participants over several months, which combined usage data with self-reported mental strain. What stood out during this period wasn’t the heavy usage. Rather, users who constantly pick up their phones for short bursts reported higher levels of overload.

This kind of behavior that involves quick checks, app switching, and short interactions, creates a pattern of continuous interruptions. So it appears to be more mentally taxing than longer, uninterrupted sessions.

Why this hits harder than long usage

The key issue here is attention.

Every time you check your phone, your brain has to shift focus, process new information, and re-engage with whatever you were doing before. Do that dozens or even hundreds of times a day, and the cognitive loads start to add up.

The study calls this fragmented use, which suggests that the pattern is what leads to feelings of being overwhelmed.

This changes how we think about phone habits

When talking about digital well-being, the most common answer is to reduce screen time. But this research points to a different problem entirely. Someone who spends hours watching a single video will end up feeling less overwhelmed than someone who checks their phone every few minutes.