Does Grayscale Reduce Phone Time? What the Studies Show

Turning your screen black and white is one of the cheapest tricks in the digital wellbeing toolbox. It costs nothing, takes a minute, and changes nothing about what apps can do. The claim attached to it is bold: that removing colour makes a phone less tempting, so you pick it up and stay on it for less time. It is fair to ask whether that is true, so here is what the published studies actually found, and what they did not.

The best-known work comes from Alex Holte and colleagues at the University of North Dakota. UC Blue Ash's write-up describes a first study of about 220 college students in which grayscale was associated with an average of 39 minutes less smartphone use per day, and a follow-up of nearly 135 participants who switched their displays to grayscale. CNN's coverage reports the same headline, nearly 40 minutes less, and adds that grayscale users in the follow-up reported feeling less compelled to check notifications. Neither article describes the study design in detail, so treat the 39 minute figure as a reported result rather than a settled number.

A second study, published in a SAGE journal in 2023 with 84 participants, used one baseline week followed by one grayscale week. Daily screen time fell by about 20 minutes. The number of times people unlocked their phone did not change, which suggests grayscale shortened the time spent per session more than it stopped people reaching for the phone. Participants reported better perceived control over their phone use, less perceived overuse and less stress. Sleep quality and productivity did not change. Because everyone took part in both weeks, there was no control group, and people may have changed behaviour simply because they knew they were being studied.

A third paper presented at the EMAC conference in 2021, by Zimmermann and Soboleve, is the closest to a proper experiment. It randomized 112 people over three weeks and compared grayscale with time limits and a tracking-only control. Grayscale produced an immediate, statistically significant drop in objectively measured screen time compared with the control. Time limits worked more gradually and by a smaller amount. The authors found no immediate effects on subjective wellbeing or academic performance, so reducing the hours did not, by itself, make people measurably happier or lift their grades within three weeks.

Put the three together and a consistent but modest picture appears. Grayscale reduced phone use by roughly 20 to 40 minutes a day in these samples, mostly in students, mostly over days or weeks. Our own reading is that for someone using their phone three to four hours a day, 20 minutes is around 10 percent, so a reduction of about a tenth is a reasonable thing to hope for and a reduction of a third would be unusual. That is our interpretation of small, short studies, not a result any of them reports. Effects vary a lot between people, and Holte himself noted that phone use differs greatly from user to user.

Why might it work? The plausible mechanism is that bright, saturated colour is part of what makes feeds, thumbnails and notification badges rewarding to look at. Remove it and the same content is flatter, so there is less pull to keep scrolling and more chance you notice you are bored and put the phone down. No study here directly proves this mechanism, and some of the effect may simply be friction and novelty: a grey screen is a small, constant reminder that you decided to use your phone differently. Novelty fades, which is why long-term follow-up matters and why we recommend pairing grayscale with other habits rather than relying on it alone.

What grayscale does not do is fix problematic use, protect a child from harmful content, or improve sleep or mood on its own. The evidence for wellbeing benefits beyond feeling more in control is thin. It also has real costs: photos, maps, charts and some games and learning apps are harder to use in black and white. That is why Mom Guard applies grayscale to the pages you choose, for the hours you choose, and lets a parent or adult exempt a site rather than forcing it everywhere.

A sensible way to test it is to run your own two-week experiment. Note your average daily screen time from your phone's built-in report for one normal week, switch to grayscale for the next, and compare. Look at both total time and how you feel, then decide whether to keep it. If you are a parent, do the same with your child as a shared experiment rather than an imposed rule, and read our guide on how to talk about it first. If your child is struggling in a way that goes beyond habits, such as sleep loss, withdrawal from friends or distress when the phone is taken away, speak to a doctor or counsellor rather than relying on settings.