When circumscribed brain regions are damaged in humans,
highly specific impairments in language, memory, problem solving,
and cognition are observed. Neurosurgery such as “split
brain” or hemispherectomy, for example, has shown that
encompassing regions, the left and right cerebral hemispheres,
each control human behavior in unique ways. Observations stretching
over 100 years of patients with unilateral focal brain damage have
revealed, without the theoretical benefits of “cognitive
neuroscience” or “cognitive psychology,” that
human behavior is indeed controlled by the brain and its neurons.