There are three main ‘parts’ of the brain that govern our nervous systems. These parts have developed over our evolution as a species. This ‘three part’ model of the brain was developed by American physician and neuroscientist Paul McLean in the 1960’s.
These three parts of the brain are not in agreement, but also do not operate independently of one another. They instead function interdependently.
The reptilian brain, the oldest of the three brains and governs vital bodily functions such as our heart rate, breathing, body temperature and balance.1
The mammalian (or limbic) brain emerged in the first mammals. It is responsible for emotions in human beings. The main structures of the limbic brain are the hippocampus, the amygdala, and the hypothalamus. The limbic brain is the seat of the value judgments that we make, often unconsciously, that have an influence on our behaviour.2
The human brain (or neocortex) first assumed importance in primates and is considered to be the logical, thinking part of the brain. This part of the brain played a role in the development of human language, abstract thought, imagination, and consciousness.3
1 Thebrain.mcgill.ca. n.d. The Brain From Top To Bottom. [online] Available at:
2 ibid.
3 Thebrain.mcgill.ca. n.d. The Brain From Top To Bottom. [online] Available at:
