Techniques to Study the Brain and Localization of Function

The biological approach in psychology rests on a foundational assumption: that behavior, cognition, and emotion have physical origins in the brain and body. To defend this assumption, psychologists need ways to observe the living brain in action. This lesson examines the major techniques used to study brain structure and function, and the closely related idea of localization of function, the theory that specific mental processes are carried out by specific brain regions.

The oldest evidence for localization comes not from technology but from clinical case studies of brain damage. In the 1860s, the French physician Paul Broca examined a patient nicknamed "Tan," so called because that syllable was almost the only sound he could produce. Tan understood language but could not speak fluently. A