It is assumed that every behaviour has its specific place in the brain and is associated with a certain brain area. This idea is known as localization of function. When talking about the brain, we discuss four key areas: the brain stem, the cerebellum, the cerebrum, and the limbic system.

• The brainstem is responsible for regulating KEY life functions, such as breathing, heart rate, and blood pressure.
• The cerebellum plays a key role in balance and motor function, including speech production.
• The cerebral cortex is the largest part of the human brain, associated with higher brain functions such as thought and action.
• The cerebrum is divided into four sections, called lobes. Each of these lobes plays a key role in behaviour. The Frontal Lobe is associated with executive functions, the Occipital Lobe is associated with visual processing, the Parietal Lobe is associated with the perception of stimuli, and the Temporal Lobe is associated with auditory processing and memory.
• The Limbic System - often referred to as the emotional brain - is a major focus of psychological research for its role in memory and emotion.

The hippocampus plays a crucial role in shaping behavior, primarily through its involvement in memory formation, spatial navigation, and emotional regulation. As a key component of the brain's limbic system, the hippocampus is responsible for converting short-term memories into long-term memories, influencing how past experiences guide present actions and decision-making. Its connection to the amygdala allows the hippocampus to influence emotional responses.

One study that supports Localization is the HM case study. The aim of this case study was to better understand the effects that an experimental surgery(where tissue from the medial temporal lobe and hippocampus was removed on both sides of HM’ brain)had on patient HM.

The procedure is as follows. Milner carried out a classic case study of the role of the hippocampus on memory formation. This was a longitudinal case study and different data collection methods were utilised. HM fell off his bicycle when he was aged 7 and sustained a serious head injury. Epileptic attacks began when he was 10. At the age of 27, he had become so incapacitated by his seizures that he could not lead a normal life and medication did not help him. With the approval of the patient and his family, neurosurgeon William Scoville performed an experimental surgery where he removed tissue from the medial temporal lobe (including the hippocampus) on both sides of HM’s brain.

After the operation, HM remembered his childhood very well. His personality appeared largely unchanged. However, HM suffered from anterograde amnesia – he was no longer able to transfer information from short-term memory to long-term memory.

The results showed that HM could not acquire new episodic knowledge (memory for events) and he could not acquire new semantic knowledge (general knowledge about the world). This suggests that the brain structures that were removed from his brain are important for long-term explicit memory and hence this supports localization.

Memories in the form of motor skills, i.e. procedural memories, were well maintained. He also showed improvements in the performance of new skills.

In conclusion the researchers concluded the hippocampus plays a critical role in converting memories of experiences from short-term memory to long-term memory. Since HM was able to retain some memories of events that happened long before his surgery it indicates that the hippocampus is not the site of permanent storage but rather plays a role in the organisation and permanent storage of memories elsewhere in the brain. This supported the theory of localisation rather than distribution since it shows that the hippocampus removal only affected memory conversion and no other skills or functions of the brain.