Urban75 Home About Offline BrixtonBuzz Contact

Study: Night tinted smartphone screens actually worse for sleep


Well, there you go.

In what should come as a surprise to no one, it turns out just making your smartphone's screen kind of yellow won't magically stop it from keeping you awake. In fact, according to a study out of the University of Manchester, that yellow-shifted "night light" is even worse for helping you get to sleep than just leaving your phone in the standard untinted mode.

The reasoning behind using a yellow tint on your screen was, at least, based on scientifically plausible principles. In your eye, a protein called melanopsin responds to the intensity of light, and specifically, it responds more strongly to light of a shorter wavelength. The wavelength of light corresponds to how we perceive its color. On your phone's screen, you typically have three "subpixels" lighting each pixel of the display, in the colors red, green, and blue. The blue subpixel has the shortest wavelength, and so the "night mode" on your phone greatly reduces the brightness of that blue subpixel, or even turns it off entirely, making the screen appear much more yellow.

But according to UoM's new study, the marginal benefit provided by making the average wavelength of the light emitted by your phone's display longer (i.e., warmer) is probably outweighed by another factor related to the ways your eyes affect your biological clock.

Their research on mice suggests that the color-sensing cone cells in your eyes are probably much more responsive to the yellow tint produced when a phone is in night mode, and that this could actually be leading to a stronger, counterbalancing effect. That is, for whatever benefit the lack of short wavelength blue light is providing in terms of those light-responsive proteins, the color-detecting cone cells in your eyes are probably playing more of a role in sending those biological signals that tell your brain whether it's day or night time.
Science now says your phone's yellow tinted 'night mode' is worse for your sleep


Spurius Bollox
My unsophisticated phone has this little feature called 'Off'. I dare say it's called 'Power Down' or 'Assume Ninja Mode' or 'Achieve Total Dormancy' on other devices.

No light of any kind and no little chirrups at 5.00 in the morning because some nutty insomniac friend has sent me a picture of something cute, or filthy.


"A top 400 poster"
It’s always interesting to see how journalists can take an exploratory study that gives nothing more than an indication for future research and somehow turn it into a “SCIENCE SAYS THIS!!!” puff piece.

The actual research notes an interesting finding about how biological photoreceptors react to different types of light. In mice. Any leap from that to human sleeping patterns is speculative. The researchers recognise that, with lots of statements saying this or that feature of the effect of colour on the brain “may be the case”. By the time the reporting makes it to this article, though, that nuance of what the study shows versus what is nothing but interesting speculation about what it all might mean has turned into the definitive statement, “yellow-shifted "night light" is even worse for helping you get to sleep than just leaving your phone in the standard untinted mode”. But the study absolutely shows no such thing one way or the other.

And then people complain that “science” keeps changing its mind when the speculation turns out to be wrong. Or even merely called into question by future exploratory research.


heckling from the back!
How's about actually asking real people ... instead of interpreting data from mice.

Another pro tip - read a paper book not a screen.


0891 50 50 50
Never bothered with 'night mode'. I always thought it sounded suss.

I know someone who used to leave it on all day, his phone screen just looked yellowish all the time. Weird.