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Getting a good night’s sleep is critical to having a productive day. A great way to prevent a good night’s sleep is to spend the last hours of the day watching TikTok videos or playing Candy Crush.

The body determines when it’s time to sleep via a number of cues, the most obvious being darkness. Staring at a light-emitting electronic screen counters these cues, and some have argued that blue light in particular is to blame. Blue light has a higher-energy wavelength, and our bodies associate its high intensity with the early hours of the day. So, such light is a cue to the body to remain alert, and it can also inhibit the pineal gland’s production of melatonin, a chemical the body produces to promote sleep.

Courtesy of iStock.com/Nattakorn Maneerat.

To address this issue, Apple added the Night Shift function to its phones and tablets in 2016 to reduce the amount of blue light emitted by its products’ screens (and arguably to extend daily use). Night Shift and similar applications work by reducing the screen’s emission of blue light to make the screen’s colors appear warmer or more red, similar to the light of the setting sun. But does the warmer light help people get more sleep?

The short answer is: probably not.

A number of studies on the subject have determined that the color-shifting feature provides no significant benefit. The Lighting Research Center at Rensselaer Polytechnic Institute examined whether Night Shift blunted the adverse effects on sleep associated with nighttime iPad use. The study determined that Night Shift’s warmer light helped to avoid melatonin suppression more than the default color settings, but not enough to create a noticeable difference in sleep quality.

More recently, a Brigham Young University (BYU) study compared sleep outcomes among subjects in three categories: those who used a phone while Night Shift was activated, those who used a phone while the function was inactivated, and those who did not use a smartphone at all before bed.

“In the whole sample, there were no differences across the three groups,” said Chad Jensen, who led the BYU study. “Night Shift is not superior to using your phone without Night Shift, or even [to] using no phone at all.”

The BYU research further suggests that the way electronic screens hinder sleep could just as easily stem from psychological effects as from physical ones. “While there is a lot of evidence suggesting that blue light increases alertness and makes it more difficult to fall asleep, it is important to think about what portion of that stimulation is light emission versus other cognitive and psychological stimulations,” Jensen said.

In other words, culprits other than blue light may be affecting our sleep when we use electronics late in the day. Psychologically stimulating activities — such as playing video games, watching TikTok videos of monkeys riding motorcycles, or trying to convince one’s uncle that the Earth is in fact round via a frustrating late-night text conversation — also likely affect our ability to achieve good rest.