Written by Robert H. Shmerling, MD, Faculty Editor, Harvard Health Publications
If you’re like me, you learned that about 90% of people are right-handed and much of the reason is genetic. And that’s true, although it remains a mystery why our genetic evolution led to so many more righties than lefties.
But for certain tasks, handedness can be “overcome.” For example, right-handed kids learning to play tennis, golf, or baseball can become successful hitting from “the other side.” It may be more a matter of how they are taught and what gets reinforced than about a hard-wired preference for one hand or the other.
According to new research, the idea of people being “left-brained” or “right-brained” may also be less fixed than we’d thought.
According to conventional wisdom, people tend to have a personality, thinking style, or way of doing things that is either right-brained or left-brained.
Those who are right-brained are supposed to be intuitive and creative free thinkers. They are “qualitative,” big-picture thinkers who experience the world in terms that are descriptive or subjective. For example, “The skies are gray and menacing; I wonder if it’s going to rain?”
Meanwhile, left-brained people tend to be more quantitative and analytical. They pay attention to details and are ruled by logic. Their view of the weather is more likely, “The forecast said there was only a 30% chance of rain but those cumulonimbus clouds will probably bring thunder as well as rain.”
A popular book first published in 1979, Drawing on the Right Side of the Brain, extends this concept. It suggests that regardless of how your brain is wired, getting in touch with your “right brain” will help you see — and draw — things differently.
These notions of “left and right brain-ness” are widespread and widely accepted. But they may also be wrong.
There is truth to the idea that some brain functions reside more on one side of the brain than the other. We know this in part from what is lost when a stroke affects a particular part of the brain. For example, it has long been thought that, in most people, control of language resides in the left side of the brain. And there are areas of the right half the brain that control movement of the left arm and leg (and vice versa). Damage to the front part of the brain is linked with reduced motivation, difficulty planning, and impaired creativity.
Meanwhile, the back of the brain (the occipital cortex) integrates visual information from the eye. Damage to this area can cause partial or complete blindness. These are just a few examples of how certain parts of the brain appear responsible for specific functions. So, location does matter.
But for more individual personality traits, such as creativity or a tendency toward the rational rather than the intuitive, there has been little or no evidence supporting a residence in one area of the brain. In fact, if you performed a CT scan, MRI scan, or even an autopsy on the brain of a mathematician and compared it to the brain of an artist, it’s unlikely you’d find much difference. And if you did the same for 1,000 mathematicians and artists, it’s unlikely that any clear pattern of difference in brain structure would emerge.
The right-brain/left brain myth?
So, is the idea of “thinking with the left side of your brain” a myth? Maybe. But, the lack of proof does not prove the opposite. For people living thousands of years ago, an inability to prove the earth was round did not prove the earth was flat!
But, the evidence discounting the left/right brain concept is accumulating. According to a 2013 study from the University of Utah, brain scans demonstrate that activity is similar on both sides of the brain regardless of one’s personality.
They looked at the brain scans of more than 1,000 young people between the ages of 7 and 29 and divided different areas of the brain into 7,000 regions to determine whether one side of the brain was more active or connected than the other side. No evidence of “sidedness” was found. The authors concluded that the notion of some people being more left-brained or right-brained is more a figure of speech than an anatomically accurate description.
The bottom line
If you’ve always thought of yourself as a “numbers person” or a creative sort, this research doesn’t change anything. But it’s probably inaccurate to link these traits to one side of your brain. We still don’t know a lot about what determines individual personality; but it seems unlikely that it’s the dominance of one side of the brain or the other that matters.
Keywords; brain, right/left brain, brain scan