Left-brain interpreter

The left-brain interpreter is a neuropsychological concept developed by the psychologist Michael S. Gazzaniga and the neuroscientist Joseph E. LeDoux. It describes the way the left cerebral hemisphere constructs explanations in order to make sense of the world, reconciling new information with what the person already knew and relating the past to the present. The idea grew out of research on split-brain patients, carried out by Gazzaniga with Roger Sperry at the California Institute of Technology in the early 1970s. When an image was shown only to the left visual field, which maps to the right hemisphere, patients said they saw nothing, yet they could still point to similar objects, which Gazzaniga took to mean the right brain could see the image but could not produce a verbal description. Later experiments, including functional MRI work, showed that the left hemisphere will construct a contrived explanation for an action whose real instruction only the right hemisphere received, and the concept has since been applied to the everyday behavior of people generally. It offers a sense of coherence and continuity but can also produce biased, self-flattering stories, and Gazzaniga himself later concluded that a simple left-brain and right-brain model is a gross oversimplification.