Answer:
Gage's case (1848) served as one of the first sources of evidence that the frontal lobe influenced personality, which became a great breakthrough during the early days of neurology. Seeing that Gage´s personality changed so much after his brain injury, helped neuroscientists understand the impact that damage to the brain could have on behavior.
Step-by-step explanation:
Gage´s case supported emerging theories at the time about certain bodily functions being associated with distinct areas of the brain. In the present, the frontal cortex has been proven as a key element of higher-order functions such as reasoning, language, and social cognition. The frontal lobes, then, hold the essence of humanity. And severe damage to the frontal lobes can change essential traits from people's personalities.