Explain how one study demonstrates localization of function in the brain.

The brain is seen as the command centre of human activity and therefore, psychologists aim to develop a deeper understanding of its role and how it matures, develops and adapts over lifetime. Prior to the development of modern scanning technology, such as FMRI or EEG, the most common ways of studying brain function and localisation was through the use of case studies which were carried out longitudinally. One of the most famous case studies that demonstrates the localisation of funtion in the brain is that of Phineas Gage in 1848.
Phineas was in a serious accident where due to an explosion, an metal pole entered Gage's left cheek, pierced the base of his skull, and exited through the top of his head. Amazingly, Phineas survived the accident with no noticeable physical problems apart from the loss of vision in his left eye. What was surprising was that after the accident the balance between his intellectual abilities and emotional control had been destroyed. He became highly agitated, irreverent and indulging. Although he could make plans for the future he could rarely follow them. He was described by his doctor (Harlow) as "a child in his intellectual capacity, but with the animal passions of a strong man". Since Gage's brain damage was located in the frontal lobe, his case study offered evidence that the frontal lobe is related to personality, social relations and planning and offered an initial base for further exploration around localisation of brain function and more specifically, on the functions of the frontal lobe.