Teens’ cell phone use linked to memory problems | Science News for Students

Teens’ cell phone use linked to memory problems

Exposure to radiation from phones might affect a certain type of memory in teens
Oct 16, 2018 — 6:45 am EST
A young woman is smiling and talking on her cell-phone

A new study finds that teens who get more exposure to cell-phone radiation — and hold their phones on the right — do worse on one type of memory test.


Teenagers who talk on the phone a lot, and hold their cell phones up to their right ears, score worse on one type of memory test. That’s the finding of a new study. That memory impairment might be one side-effect of the radiation that phones use to keep us connected while we're on the go.

Nearly 700 Swiss teens took part in a test of figural memory. This type helps us recall abstract symbols and shapes, explains Milena Foerster. She’s an epidemiologist. That’s someone who studies disease patterns within a population. She worked on the study as part of a team while Foerster was at the Swiss Tropical and Public Health Institute in Basel, Switzerland. (She is now at the World Health Organization’s International Agency for Research on Cancer in Lyon, France.)

Teens participated in memory tests twice, one year apart. Each time, they had one minute to memorize 13 pairs of abstract shapes. Then they were shown one item from each pair and asked to match it with one of five choices.

The study volunteers also took a test of verbal memory. That’s the ability to remember words. The two memory tests are parts of an intelligence test.

The researchers also surveyed the teens on how they use mobile phones. And they got call records from phone companies. The researchers used those records to estimate how long the teens were using their phones. This allowed the researchers to calculate how big a radiation exposure each person could have gotten while talking.

All cell phones give off energy in the form of radiofrequency electromagnetic fields, or RF-EMFs. Radio and TV broadcasts also use this type of energy. So do microwave ovens and some other gadgets.

For a phone, that energy carries information, in the form of calls or texts between phones and cell phone towers. That radiation also can travel into people’s bodies as they use their phones. And some of its energy can be absorbed by the body. So far, scientists have not shown that radiation from phones causes harm, says the Federal Communications Commission. Research is ongoing, this U.S. agency notes.  

three cell phone towers in the distance
Mobile phones send and receive data from cell phone towers in the form of electromagnetic energy. They use a type of energy called a radiofrequency electromagnetic field, or RF-EMF.

A phone user’s exposure to RF-EMFs can vary widely. Some teens talk on their phone more than others. People also hold their phones differently. If the phone is close to the ear, more radiation may enter the body, Foerster notes.

Even the type of network signal that a phone uses can matter. Much of Switzerland was using an older “second-generation” type of cell-phone network when the group collected its data. That type of network can expose people to between 100 and 500 times as much RF-EMF radiation as newer networks, the study reports. Many phone carriers have moved away from such networks. And more companies plan to update their networks within the next few years.

The teens’ scores in the figural memory tests were roughly the same from one year to the next. But those who normally held their phone near their right ear, and who were also exposed to higher levels of radiation, scored a little bit worse after a year. No group of teens showed notable changes on the verbal memory test.

Why might one type of memory be linked to cell phone use, but not another? Foerster and her colleagues think it could have to do where different memory centers sit in the brain. The site that deals with the ability to remember shapes is near the right ear. “This may suggest that indeed RF-EMF absorbed by the brain is responsible” for the results, said coauthor Martin Röösli. He, too, is an epidemiologist in Basel at the Swiss Tropical and Public Health Institute.

The report was published last July in Environmental Health Perspectives.

Should you worry?

There’s no need to swear off your cell phone yet. For one thing, the link was not very strong between the estimated radiation dose and drop in their memory scores for some teens.

It’s also hard to gauge both radiation exposure and phone use precisely. Teens thought that they spent much more time talking on the phone than they actually did, according to call records. But the researchers only had call records for some of the study’s teens. So they had to estimate how much time the others had spent on their phones. And records from phone companies likely wouldn’t include calls on phone apps such as WhatsApp or Skype.

What’s more, a correlation between two things does not prove one caused the other. “I would not draw any causal conclusions from our study,” says Foerster. The findings, her team says, should be viewed only as “preliminary evidence.”

John Bucher is a toxicologist at the National Toxicology Program, or NTP, in Durham, N.C. That’s part of the National Institutes of Health. He did not work on the new study but noted the same limitations that Foerster’s group did. He did point out, however, that the study “was carefully done and took many factors into consideration.”

Bucher’s team has also studied effects of cell phone radiation — in rodents. Male rats that got high doses of the radiation had a higher cancer risk, the group found. That was not the case for female rats or mice.

“Because the animals were exposed to levels much higher than what people typically receive from cell phones, the [NTP] results cannot be directly applied to people,” Bucher says. Yet “they provide valuable information to help guide future studies of cell-phone safety as the technologies advance.”

A peer-review panel at NTP accepted the findings by Bucher’s group earlier this year, in March. Technical reports describing their findings are due to be published soon.

The U.S. Food and Drug Administration has tips for people who want to reduce their radiation exposure from phones, Bucher adds. Spend less time on your cell phone, it recommends. And use the phone’s speaker or a headset to keep the actual phone away from your ear.

Foerster agrees that it makes sense to take those simple steps. “In general,” she says, “the radiation decreases very, very fast as you increase the distance from the device.”

Power Words

(more about Power Words)

abstract     Something that exists as an idea or thought but not concrete or tangible (touchable) in the real world. Beauty, love and memory are abstractions; cars, trees and water are concrete and tangible.

app     Short for application, or a computer program designed for a specific task.

cancer     Any of more than 100 different diseases, each characterized by the rapid, uncontrolled growth of abnormal cells. The development and growth of cancers, also known as malignancies, can lead to tumors, pain and death.

coauthor     One of a group (two or more people) who together had prepared a written work, such as a book, report or research paper. Not all coauthors may have contributed equally.

colleague     Someone who works with another; a co-worker or team member.

correlation     A mutual relationship or connection between two variables. When there is a positive correlation, an increase in one variable is associated with an increase in the other. (For instance, scientists might correlate an increase in time spent watching TV with an increase in rates of obesity.) Where there is an inverse correlation, an increase in one value is associated with a drop in the other. (Scientists might correlate an increase in TV watching with a decrease in time spent exercising each week.) A correlation between two variables does not necessarily mean one is causing the other.

electromagnetic     An adjective referring to light radiation, to magnetism or to both.

environmental health     A research field that focuses on measuring the effects of pollutants and other factors in the environment on the health of people, wildlife or ecosystems.

epidemiologist     Like health detectives, these researchers figure out what causes a particular illness and how to limit its spread.

factor     Something that plays a role in a particular condition or event; a contributor.

federal     Of or related to a country’s national government (not to any state or local government within that nation). For instance, the National Science Foundation and National Institutes of Health are both agencies of the U.S. federal government.

field      (in physics) A region in space where certain physical effects operate, such as magnetism (created by a magnetic field), gravity (by a gravitational field), mass (by a Higgs field) or electricity (by an electrical field).

Food and Drug Administration (or FDA)     A part of the U.S. Department of Health and Human Services, FDA is charged with overseeing the safety of many products. For instance, it is responsible for making sure drugs are properly labeled, safe and effective; that cosmetics and food supplements are safe and properly labeled; and that tobacco products are regulated.

gauge     A device to measure the size or volume of something. For instance, tide gauges track the ever-changing height of coastal water levels throughout the day. Or any system or event that can be used to estimate the size or magnitude of something else. (v. to gauge) The act of measuring or estimating the size of something.

generation     A group of individuals (in any species) born at about the same time or that are regarded as a single group. Your parents belong to one generation of your family, for example, and your grandparents to another. Similarly, you and everyone within a few years of your age across the planet are referred to as belonging to a particular generation of humans. The term also is sometimes extended to year classes of other animals or to types of inanimate objects (such as electronics or automobiles).

intelligence     The ability to collect and apply knowledge and skills.

link     A connection between two people or things.

National Institutes of Health (or NIH)     This is the largest biomedical research organization in the world. A part of the U.S. government, it consists of 21 separate institutes — such as the National Cancer Institute and the National Human Genome Research Institute — and six additional centers. Most are located on a 300 acre facility in Bethesda, Md., a campus containing 75 buildings. The institutes employ nearly 6,000 scientists and provide research funding to more than 300,000 additional researchers working at more than 2,500 other institutions around the world.

network     A group of interconnected people or things. (v.) The act of connecting with other people who work in a given area or do similar thing (such as artists, business leaders or medical-support groups), often by going to gatherings where such people would be expected, and then chatting them up. (n. networking)

peer review   (in science) A process in which scientists in a field carefully read and critique the work of their peers before it is published in a scientific journal. Peer review helps to prevent sloppy science and bad mistakes from being published.

population     (in biology) A group of individuals from the same species that lives in the same area.

preliminary     An early step or stage that precedes something more important.

radiation     (in physics) One of the three major ways that energy is transferred. (The other two are conduction and convection.) In radiation, electromagnetic waves carry energy from one place to another. Unlike conduction and convection, which need material to help transfer the energy, radiation can transfer energy across empty space.

radio     To send and receive radio waves, or the device that receives these transmissions.

risk     The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)

rodent     A mammal of the order Rodentia, a group that includes mice, rats, squirrels, guinea pigs, hamsters and porcupines.

toxicologist     A scientist who investigates the potential harm posed by physical agents in the environment. These may include materials to which we may be intentionally exposed, such as chemicals, cigarette smoke and foods, or materials to which we are exposed without choice, such as air and water pollutants. Toxicologists may study the risks such exposures cause, how they produce harm or how they move throughout the environment.

toxicology     The branch of science that probes poisons and how they disrupt the health of people and other organisms. Scientists who work in this field are called toxicologists .

World Health Organization     An agency of the United Nations, established in 1948, to promote health and to control communicable diseases. It is based in Geneva, Switzerland. The United Nations relies on the WHO for providing international leadership on global health matters. This organization also helps shape the research agenda for health issues and sets standards for pollutants and other things that could pose a risk to health. WHO also regularly reviews data to set policies for maintaining health and a healthy environment.


Journal:​ ​​M. Foerster​ ​et​ ​al.​ ​A prospective cohort study of adolescents’ memory performance and individual brain dose of microwave radiation from wireless communication.​ ​​Environmental Health Perspectives.​ ​​Vol.​ ​126,​ ​July 23, 2018. doi:  10.1289/EHP2427.

Website: U.S. National Cancer Institute. Cell Phones and Cancer Risk.

Technical Report:​​ National Toxicology Program.​ Toxicology and carcinogenesis studies in Hsd: Sprague Dawley SD rats exposed to whole-body radio frequency radiation at a frequency (900 MHz) and modulations (GSM and CDMA) used by cell phones. TR-595. Peer-reviewed draft, March 28, 2018. 381 pp.

Technical Report:​​ National Toxicology Program.​ Toxicology and carcinogenesis studies in B6C3F1/N mice exposed to whole-body radio frequency radiation at a frequency (1,900 MHz) and modulations (GSM and CDMA) used by cell phones. TR-596. Peer-reviewed draft, March 28, 2018. 270 pp.