Teenagers who talk on the cell phone a lot, and hold their 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(放射线) that phones use to keep us connected while we're on the go.
The teens took memory tests twice, one year apart. Nearly 700 Swiss teens took part in a test of figural memory. This type helps us remember abstract(抽象的) symbols and shapes, explains Milena Foerster. Each time, they had one minute to remember 13 pairs of abstract shapes. Then they were shown one item from each pair and asked to match it with one of the five choices. The study volunteers also took a test of verbal memory. That's the ability to remember words. The two memory tests are part of an intelligence test.
The researchers also surveyed the teens on how they use cell phones. And they got call records from phone companies. The researchers used those records to figure out how long the teens were using their phones.
This allowed the researchers to work out how big radiation exposure(接触) each person could have got while talking.
A phone user's exposure to the radiation can differ widely. Some teens talk on their phone s more than others. People also hold their phone s differently. If the phone is close to the ear, more radiation may enter the body, Foerster notes.
The teens' scores in the figural memory tests were roughly the same from one year to the next. But those who normally held their phones near the right ears, and who were also exposed to higher levels of radiation, scored a little bit worse after a year. No group of teens showed big changes on the verbal memory test. Why might one type of memory be linked to cell phone use, but not another? Foerster thinks it could have to do with where different memory centers sit in the brain. The site that deals with the ability to remember shapes is near the right ear.
