The impact of smartphone thumbing on your brain

Almost like a new drug, our addiction to using our smartphones is having a profound effect on our brains. Whether we’re texting, posting on Facebook, or playing Angry Birds, the way we’re repetitively using our fingers and thumbs on the smooth surface of a touch screen is causing certain areas of our brains to become bigger. In other words, we’re experiencing heightened brain activity that rewires sensory processing when our fingertips and thumbs are touched, a phenomenon known as “brain plasticity” in which the brain adapts to learning new things.

For expert groups like violinists or video game players that have already been studied at length, brain plasticity explains why the region of their brains relating to the agility of their fingers is bigger than that of the average person. Researchers from the University of Zurich and ETH Zurich wondered if the brains of average people would also change with repetitive activities in everyday life. Smartphones gave them the perfect opportunity to study this, not only because so many people use smartphones constantly, but also because they contain a database of our battery usage that can be cross-referenced against the results of medical testing of our brains.

Using electroencephalography (EEGs), the Swiss researchers compared the brain activity of touch screen smartphone users to that of mobile phones users with older-style keypads. The EEGs recorded the response of each person’s brain to the mechanical touch of their thumbs as well as the tips of their index and middle fingers. The battery usage logs in smartphones helped the researchers to determine when and how much the smartphones were being used.

At the conclusion of their study, the researchers found that individuals using touch screen smartphones demonstrated more brain activity when their thumbs and fingertips were touched than the individuals who used mobile phones with keypads.

But it didn’t stop there. Looking at just the smartphone users, the researchers discovered that these people showed more brain activity when all three fingertips were touched. Although it didn’t matter how long an individual had owned a smartphone with a touch screen, brain activity was influenced by how much that smartphone was used, how recently, and which fingertip was touched. Specifically, the more usage of a smartphone within the last 10 days, the greater the brain activity, with the highest activity recorded when a person’s thumb was used. The thumb was also sensitive to daily changes in usage. Shorter lapses of time between intense smartphone usage was associated with more brain activity.

“The digital technology we use on a daily basis shapes the sensory processing in our brains, and on a scale that surprised us,” concluded lead researcher Arko Ghosh.