In 1861, Pierre Paul Broca, a French surgeon, had a patient he referred to as “Tan.” After an accident, the patient had become aphasiac, meaning he could not speak. The only word he could utter was "tan" (think Hodor in Game of Thrones). Broca hypothesized that an area on the left side of the brain controlled speech, and when it sustained damage, people couldn’t speak (now called the Broca’s area).
This early discovery led to the theory that different hemispheres of the brain, left and right, controlled various functions, such as speech or logic. And this evolved into the idea that the dominant side of the brain affected personality characteristics—left-brain people are thought to be more analytic, objective, and logical, while right-brain people are believed to be more creative and insightful. Now, researchers have discovered that they can determine whether someone is a left- or right-brain person by looking at how they use their cell phones.
Researchers at the Henry Ford Medical Center at Detroit wondered why people held their cell phones on one particular ear, and suspected that being left- or right-brained influenced it—between 70 and 95 percent of the population is right-handed and, of these people, 96 percent are left-hemisphere dominant.
The researchers asked 717 subjects to fill out an online survey, which determined their hemispheric dominance (left or right) and how they used their cell phone. Of the subjects, 90 percent were right handed and 9 percent were left handed. The researchers found that 68 percent of the righties held their phones to their right ear and 25 percent to the left, while 7 percent couldn’t commit to a side. Seventy-two percent of southpaws held their phones to the left side, 23 to the right side, and 5 percent had no preference. The average cell phone usage amounted to about 540 minutes per month over the past nine years.
The researchers note that there is a 73 percent association between hand dominance and the side people hold their cell phones—so how we use our cell phones allows people to predict whether someone is right- or left-brain dominant. While understanding this connection could lead to better cell phone design, the researchers believe it will help them better understand the relationship between mobile phones and brain tumors and help them improve brain imaging techniques.
"Our findings have several implications, especially for mapping the language center of the brain," says Michael Seidman, director of the division of otologic and neurotologic surgery at Henry Ford and one of the authors of the paper.
"By establishing a correlation between cerebral dominance and sidedness of cell phone use, it may be possible to develop a less-invasive, lower-cost option to establish the side of the brain where speech and language occurs.”
The paper appears in JAMA Otolaryngology—Head & Neck Surgery.