Phineas Gage was 25 years old and had a job working on a railroad in 1848. As he was tamping down explosives, they went off and sent the iron tamping rod through his head, from the jaw through the top of his skull. Gage lost vision in one eye, but surprisingly recovered and survived for another 13 years. Scientists who studied Gage's case learned enough to begin removing brain tumors and performing lobotomies. But Gage had trouble holding a job because of changes in his personality. He would drink, fight, gamble, and consort with prostitutes. Scientists called this "disinhibition," and attributed it to his brain injury. It became a theory that his damaged frontal lobe was the center of inhibition that kept most people from doing things they shouldn't. Gage became patient zero for the science of personality by brain mapping.
Another case of a personality change after a brain injury involves Eadweard Muybridge. Muybridge became both eccentric and creatively productive after a brain injury, but he also shot and killed a guy. Was this frontal lobe disinhibition? The case of Muybridge is not so clear-cut, because it was much better documented. That brings up the question of whether Gage's personality really did change. The actual evidence is scant, and what is there could be explained by the life-changing trauma of his accident. And Gage's and Muybridge's behaviors were ultimately judged by different scales. Read about science's new look at the case of Phineas Gage at Aeon, or here if you're out of free articles. -via Metafilter
(Image credit: Originally from the collection of Jack and Beverly Wilgus, and now in the Warren Anatomical Museum, Harvard Medical School)