The myth of left- or right-brained dominance has become a convenient way to explain away our personality quirks, but these neuroscientists are setting the record straight.
There are hundreds of personality quizzes online that claim to tell you, based on criteria ranging from your preference in paintings to your reported ability to recall names and faces, whether the right or left half of your brain is dominant. Left-brained people, the quizzes will tell you, are logical and excel at language and math; right-brained people are more imaginative, emotionally intelligent and skilled with spatial reasoning. There’s just one problem: That’s not how brains work.
Several 19th-century neurologists, for example, noted the presence of lesions in the left frontal lobes of several patients with speech disorders. Broca’s area, the language center of the brain, was thus named after the most famous scientist to document this connection. In the 1960s, California Institute of Technology neuropsychologist Roger Sperry and doctoral student Mike Gazzaniga worked with four so-called “split-brain” patients who had undergone this surgery. They found subtle but surprising differences in the way the patients processed the world around them., Sperry and Gazzaniga gave the patients a spoon to hold in their right hands and asked them to identify the object without looking.
In their 2013 study, Anderson and his colleagues conducted statistical analyses of over 1,000 brain scans. “In every individual, there would be some connections that are stronger in the left hemisphere and some in the right. And that varied on a connection-by-connection level,” he says. “People had roughly equal mixes of both. When you average it out, it wasn’t the case that one individual would tend to have stronger connections on the whole in the left hemisphere.