The neurones making up the human brain have more interconnections than there are atoms in the universe. Winston explains that in the course of human evolution, spanning over two and a half million years, the volume of the brain has increased from half a litre to one and a half litres. This represents an increase of about 150,000 nerve cells in the brain for each generation up to about 100,000 years ago, since which time its size has remained constant. The brain of an adult uses up about one-fifth of the body's energy needs. The cerebellum or lower brain, also known as the reptile brain, is similar in structure in most vertebrate animals.
Humans are able to perform such seemingly basic tasks as running, sitting or standing automatically.
This frees the higher brain or cerebrum for more complex tasks. In humans the main evolutionary development of the brain has taken place in the cerebrum. This resembles the wrinkled bilateral shape of a walnut. The highly convoluted surface permits many more interconnections between neurones which gives the human brain its enormous cognitive power. The programme explained the unique qualities of mankind by showing the diverse elements brought together in humans through the process of biological and social evolution.