Perth, Are you logical, detail-oriented or good with numbers?
You must be “left-brained”.
Personality quizzes and career advice passed down through generations have many of us thinking we’re powered by one side of our brain that dominates our thinking style and explains our personality. The science behind this idea goes all the way back to the 1860s. That’s when French doctor Paul Broca found speech was controlled mainly by the left side of the brain. This was the first evidence the brain’s two halves may have separate roles.
A century later, Nobel laureate Roger Sperry extended this idea. He and his team studied people who’d had brain surgery to control their epilepsy. The surgery involved cutting the nerve fibres connecting the left and right sides of the brain, allowing them to examine each side individually. For the first time, they could see what each hemisphere controlled. They found the left side was more specialised for controlling language and the right for emotional and non-verbal processing. The separation of tasks into one side or the other, or lateralised behaviour, is not a uniquely human trait. Insects, fish, birds and other mammals do it too, not just primates. They thought that if the control of personality traits was limited to one hemisphere, they would see consistent patterns of brain activity between brain regions on one side. The researchers found some functions are concentrated in a particular side of the brain.
But the general public then interpreted “some functions are mainly controlled by one side of the brain” as “all people are either left-brained or right-brained” – a way to explain why we can think and feel differently to other people.
These were around the areas and in the sides related to control of language and attention – similar to what had been flagged years previously.
