When you spend time interacting with your smartphone via touchscreen, new research shows that it actually changes the way your thumbs and brain work together.
In fact, using that tiny screen directly translates into greater brain activity when the thumbs and other fingertips are touched.
Fingertip-associated brain signals
“I was really surprised by the scale of the changes introduced by the use of smartphones,” says Arko Ghosh of the University of Zurich and ETH Zurich in Switzerland. “I was also struck by how much of the inter-individual variations in the fingertip-associated brain signals could be simply explained by evaluating the smartphone logs.”
It all started when Ghosh and his colleagues realized that our newfound obsession with smartphones could be a great opportunity to explore the everyday plasticity of the human brain.
Not only are people suddenly using their fingertips — and especially their thumbs — in a new way, but many of us are also doing it an awful lot, day after day. Our phones are also keeping track of our digital histories to provide a ready-made source of data on those behaviors.
Ghosh explains it this way: “I think first we must appreciate how common personal digital devices are and how densely people use them. What this means for us neuroscientists is that the digital history we carry in our pockets has an enormous amount of information on how we use our fingertips (and more).”
Every region of the body — from the toes to the jaw and tongue — has a particular processing area in our emotional center in the brain, the somatosensory cortex. These areas are flexible and can change. In the case of violinists, for instance, the area representing the fingers that guide the instrument is larger than in other people.
While neuroscientists have long studied brain plasticity in expert groups — like musicians or video gamers — smartphones present an opportunity to understand how regular life shapes the brains of regular people.
To link digital footprints to brain activity in the new study, Ghosh and his team used electroencephalography (EEG) to record the brain response to mechanical touch on the thumb, index, and middle fingertips of touchscreen phone users in comparison to people who still haven’t given up their old-school mobile phones.
The researchers found that the electrical activity in the brains of smartphone users was enhanced when all three fingertips were touched. In fact, the amount of activity in the cortex of the brain associated with the thumb and index fingertips was directly proportional to the intensity of phone use, as quantified by built-in battery logs.
The thumb tip was even sensitive to day-to-day fluctuations: the shorter the time elapsed from an episode of intense phone use, the researchers report, the larger was the cortical potential associated with it.
The results suggest to the researchers that repetitive movements over the smooth touchscreen surface reshape sensory processing from the hand, with daily updates in the brain’s representation of the fingertips. And that leads to a pretty remarkable idea: “We propose that cortical sensory processing in the contemporary brain is continuously shaped by personal digital technology,” Ghosh and his colleagues write.
What exactly this influence of digital technology means for us in other areas of our lives is a question for another day. The news might not be so good, Ghosh and colleagues say, noting evidence that links excessive phone use with motor dysfunctions and pain.