Cell phones are great. But they also have potential costs and dangers. We looked at the research.
Both of my kids are in middle school. Both now have a phone. The decision to provide my kids with cell phones—and the ongoing negotiations about how and when to use them—left me wondering about how cell phones can affect their lives.
Cell phones offer some clear benefits to parents and kids. Most notably, keeping in touch: knowing where they’re at, knowing when they’ll be home, being available if they need someone to talk to. In an era where families frequently relocate for work, cell phones can be great ways of staying in touch with friends and family that we might not otherwise see. Moreover, many people find supportive communities of like-minded people online, which they can stay in touch with through their phones.
But cell phones also come with some potential costs. As in several industries, research trails innovation. But here’s what we know so far:
Phones can impact how we learn. Actual interruptions by phones (ringing, notifications, etc.) do seem to cause learning and memory impairment when tested in the lab for pretty obvious reasons (you’re paying attention to something else). This is a quite well-substantiated effect.
Phones don’t have to ring to negatively impact learning outcomes. Just the mere presence of phones can impair memory. This seems particularly acute among people who report feeling dependent on their phone. The overall effect, however, hasn’t always been replicated in follow-up studies.
What about long-term use? There aren’t many studies addressing this question. One study found the amount that you use your phone / your phone behaviors at age 9 are negatively associated with test scores later. And further cell phone use is negatively associated with learning outcomes throughout those years. At least according to this research, “later is better”: students who didn’t get cell phones by 9 years of age significantly outperformed their peers who had gotten cell phones by that age.
One of the frequent uses of cell phones is to take pictures and post them on social media—pictures of food, vacations, workouts, and other experiences. Ironically, doing so can lead to worse memories for the events themselves.
Much depends on how the photo is taken. Taking photos can lead to richer memories for the visual aspects of the specific thing being photographed (as you’re taking the photo, you’re likely paying attention to how it looks), but at the expense of remembering more about the surrounding environment.
Distracted driving is one of the main, primary risks of cell phones. It is also one of the most well-studied ones.”
Generally speaking, using cell phones before bed increases sleep loss, through several different mechanisms. There is a psychological component: thinking about messages right before bed can make you feel less relaxed, and anticipating notifications can do the same. And there is at least one physiological component: the brightness of the screen affects melatonin production (melatonin makes people feel sleepy).
Sleep loss seems particularly acute for those who report high dependency on their phone (e.g., they feel as though they “need” their phone or can’t live without it). One study found that young adults who reported feeling dependent on their phone got roughly two-and-a-half fewer hours of sleep per night than their peers. And sleep deprivation is associated with various forms of cognitive dysfunction.
Blue light filters can reduce some of the physiological effects. But the best thing to do is probably just to leave the cell phone off (or out of reach) for the hour or so before bed.
Pediatricians have long argued that “screen-time” — time spent passively in front of TVs, tablets, cell phones, or any other entertainment device — should be minimized for young children (and, ideally, eliminated for children under 2). Lots of research demonstrates that excessive time in front of screens impacts social, emotional, and cognitive development.
There are some reasons why this doesn’t necessarily apply to cell phones, however. Like tablets, cell phones are often used interactively (instead of just passively). They are portable, and can be used in different contexts. When used with someone else, they can promote joint attention, as with looking together at a photo, a video, or a game.
All of these aspects of cell phones make them potentially less harmful than spending lots of time in front of a TV. But if children are passively watching videos on their phone for hours on end, the usual recommendations against screen time apply.
Phones don’t have to ring to negatively impact learning outcomes. Just the mere presence of phones can impair memory.”
A line of research has explored how cell phones impact our social lives. Certainly, the numerous messaging, social media, and social gaming apps can help children stay in touch with friends. High social media use, however, may very well cause unhappiness.
There are also, however, some more subtle impacts that cell phones seem to make. People with phones around, for example, smile less often (and less genuinely) at strangers. Another study suggests that frequent phone use can lead to less self-reflection among young adults. A final summary of recent research suggests that the presence of smartphones simply diminishes the richness and depth of social relationships.
Other research suggests that the rise of smartphone use has fueled a recent increase in depression and suicide among teenagers. If so, the authors argue that one of the main reasons for the link is diminished face-to-face interpersonal time, which tends to improve mood.
Driving While Phoned
Distracted driving is one of the main, primary risks of cell phones. It is also one of the most well-studied ones.
By one estimate, distracted driving causes around 6,000 deaths a year. Young, inexperienced drivers are already at high risk for driving accidents when compared with older, more experienced drivers. They’re less likely to see hazards, more likely to take risks, and more likely to overestimate their abilities.
So no one should be using cell phones while driving. But young adults should REALLY not use phones. The impact of phones on driving comes primarily from being distracted—through visuals, sounds, physically using the phone, or just thinking about it. So “hands-free” phones do not eliminate the risk. Conversations on a cell phone are qualitatively different from in-person passenger conversations (which can also distract drivers, but to a much lesser extent). Texting is particularly dangerous, involving visual, cognitive, and physical distractions.
The solution? Turn phones off or use airplane mode when driving. If using GPS, set it up beforehand and leave it alone until you reach your destination.
Lots of research demonstrates that excessive time in front of screens impacts social, emotional, and cognitive development.”
The Cancer Question
Finally, there’s the question of cancer. I left this one for last— because the research on whether cell phones cause cancer through radio frequency radiation is a mess. And it will likely continue to be so for quite some time.
To be sure, there’s studies that find a connection between cancer rates and cell phone use. There are studies that find no connection. There are publicly funded studies and industry funded studies. And there are conflicting interpretations about what the very same study shows.
Cultural change can also impact our views of prior research. One of the largest cohort studies found that using the phone for a half-hour a day was extremely high use. Now that looks like peanuts compared to how often people glue themselves to their phone.
Technological change can also make prior research outdated: the switch from analog to digital technology, for example, lowered the average power levels of phones. So then the question was, even if there was a link before, is there a link now, with new lower power levels? New technology (like the switch to 5G) can also mean higher power levels than before, raising the opposite question: if there wasn’t a link before, now might there be?
The upshot is: scientists are still divided on this issue. But frequent long-term use of cell phones (on the order of years and many hours a day) seems to be associated with increased risk for certain forms of cancers and tumors. The mechanisms behind this aren’t well understood. And multiple large studies are ongoing to test the link between the two, especially the risk to children.
There are good reasons to think that children are more vulnerable. Children’s skulls are thinner than adults, their overall size is smaller, and their brains have more water, potentially increasing the risk. And if you start using a phone early, it’ll be more total exposure by the time that you grow old.
The increased risk is probably quite small. And it seems to require a lot of use to increase your risk. That said, it just seems prudent to avoid excessive use.
The further the antenna is away from your head, the better. So headsets, video chats, anything that keeps the phone away from your head is good. When phones are trying to find a signal they use more power; that’s why you might find differences between rural areas, whose antennas are (generally speaking) further away, and urban areas, whose antennas tend to be closer. Turning off your antenna entirely when you’re not using it (i.e., putting your phone into airplane mode or simply turning it off) is another way of avoiding excessive exposure.
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