​In 1868, Phineas Gage, a young foreman on a work crew, had…

​In 1868, Phineas Gage, a young foreman on a work crew, had a 13-pound steel rod impaled into the front of his brain by an explosion of dynamite. Amazingly, he survived the accident; and within two months, Gage could walk, talk, and move normally, but the injury forever changed his personality. Dr. Harlow carefully recorded all details of this accidental frontal lobotomy. Dr. Harlow used which research method in documenting Phineas Gage’s behavior?