New research shows that the taken-for-granted idea of being a "left-hand-brain" personality or vice versa is nonsense.
Is your desk organised? Do you turn your head to the right when someone asks you a question? Do you read instructions for assembling something? These questions are meant to help you to decide whether you are right- or left-brained – creative and thoughtful (right) or logical and analytical (left). There are hundreds of quizzes online to help you to figure out which side of your brain is dominant.
But last week, researchers from the University of Utah released a study that found that the whole concept of left- and right-brain dominance is a load of nonsense. The research was published in online medical journal PlosOne earlier this month.
The left-brain, right-brain personality test is based on the assumption that people are either one type or the other and that there is corresponding activity in each brain hemisphere.
For the study, researchers analysed resting brain scans of more than 1?000 people between the ages of seven and 29. Over two years, the scientists looked at thousands of brain regions and found that none of the subjects preferred one side over the other.
The brain scans were sourced from the International Neuroimaging Data-Sharing Initiative, and involved each participant lying for five to 10 minutes in a specialised magnetic resonance imaging (MRI) scanner that maps brain activity.
"It's absolutely true that some brain functions occur in one or the other side of the brain," said lead author Jeff Anderson, principal investigator for the Utah Functional Neuroimaging Laboratory.
"Language tends to be on the left, attention more on the right. But people don't tend to have a stronger left- or right-side brain network. It seems to be determined more by connection [of brain regions]."
His team analysed 7?000 brain regions and examined the tissues, looking for connections before adding up the activity in each hemisphere.
"Everyone should understand the personality types associated with 'left-brained' and 'right-brained' and how they relate to him or her personally," said Jared Nielsen, a neuroscience postgraduate student who was involved in the research.
"However, we just don't see patterns where the whole left-brain network is more connected or the whole right-brain network is more connected in some people. It may be that personality types have nothing to do with one hemisphere being more active, stronger or more connected."
Incidentally, the question "Do you read instructions before assembling something?" is a trick question. Nobody does. You only turn to the instructions after hours of trying without them.