The intelligence of the ancestors of man cannot be judged by the size of the skull

Anthropologists have studied the development of the human mind for decades, exploring the tools found during the archaeological excavations, evidence of fire use, etc. change the size of the brain , scientists have produced fossil skulls. Recently, however, scientists from the University of Witwatersrand in South Africa have discovered a new way of assessing intelligence of our ancestors. Studying the fossil skull, the researchers determined how much blood and how much energy was required the brain of ancient hominids, to continue to work.

The speed of blood flow in the brain — an indicator of cognitive abilities

In the past, scientists believed that the brain size of human ancestors testified about the level of intellectual development of hominids. However, in the course of the work, published in the journal Proceedings of the Royal Society. B researchers found that blood flow in the brain may be a better indicator of cognitive abilities than brain size. The results obtained conclude that the intelligence of ancient people is directly dependent on the size of the brain is untenable. The thing is, for the living of primates the number of nerve cells in the brain almost in proportion to the volume of the brain. Other studies of mammals in General show that the rate of metabolism of the brain — the amount of energy required for work — is almost proportional to its size.

Information processing in the brain involves the nerve cells (neurons) and connections between them (synapses). The human brain contains over 80 billion neurons and 1000 trillion occupies only two percent of the body, the brain consumes about 20% of the energy when the person is at rest. The remaining 70% of the energy used by the synapses for the production awash with neurochemicals that transmit information between neurons.

To understand how much energy is used the brains of our ancestors, scientists have focused on the speed of the blood flow to the brain. Since blood supplies the brain with necessary oxygen, it is closely connected with the use of synaptic energy. Every second, the brain requires about 10 ml of blood. This number varies from person is awake, sleeping, training or solve complex mathematical problems.

In this regard, the researchers propose to consider the brain as a rather energy-intensive supercomputer. The more capacity the computer has, the more energy he needs for the job — and the greater must be the electrical power cables. Same thing with the brain: higher cognitive functions, the higher the rate of metabolism, the greater the blood flow and the more of the arteries that supply blood to the brain. Scientists have found that the circulatory system regulates the size of blood vessels to match the speed of blood flow in them. Flow velocity, in turn, depends on how much oxygen is required by the body.