However, it soon became apparent, even to Broca, that exceptions and mismatches existed, and that perhaps the association was not as fixed as he had initially thought. Indeed, for almost a century, until the Wada test (a technique involving the anaesthetizing of one side of the brain using a drug such as sodium amytal or sodium amobarbital) was introduced in the 1960s, a person’s handedness was just about the only clue an operating neurosurgeon had about which hemisphere of a patient’s brain was probably the one specialized for language.įollowing Broca's findings, it was initially assumed that handedness and the hemispheric dominance of speech processing were inextricably and intimately connected. It was the French physiologist Paul Broca in the 1860s (as well as his less well-known countryman and near contemporary, Marc Dax, almost 30 years earlier) who noted that, at least in general terms, a person’s handedness tends to indicate a specialized hemisphere on the brain's opposite side, so that a right-handed person probably has a left-hemisphere language specialization, and vice versa. This lateralization and specialization of different areas of the brain is much more marked in humans than in animals, and becomes increasingly marked as we progress for early childhood to adulthood. Mathematical, analytical and logical processing are also usually carried out in the left hemisphere, while spatial recognition, face recognition, sense perception, emotion processing and artistic functions usually occur in the right.
A good example of this is the two areas of the brain where speech production and language comprehension are processed (known as Broca’s area and Wernicke’s area respectively), both of which are usually located in the left hemisphere of the brain.
Left brain dominant traits full#
Most, but not all, of the different structures, lobes and organs of the brain have a left and right hemisphere element, and communication between the hemispheres is achieved by means of a thick bundle of nerve tissues known as the corpus callosum, which effectively makes a full brain out of two half-brains.īut the two halves of the brain are not exactly alike, and each hemisphere tends to have some functional specializations, where the neural mechanisms of a particular brain function are localized primarily in one half of the brain. Also well-known is that the brain is “cross-wired”, with the left hemisphere controlling movement on the right side of the body, and the right hemisphere controlling the left side of the body.
Right, Left, Right, Wrong! - Handedness and the BrainĪs is quite well-known, the brain is split into two roughly similar hemispheres, separated by the deep longitudinal fissure.