The AVERAGE brain of an adult weighs between 1,300 and 1,400 grams and is about 15 centimeters long. But that was not always the case. A new study reveals that the size of the human brain has decreased significantly in the last 50,000 years.
The study was published in the journal Brain, Behavior and Evolution, and the scientist of the Natural History Museum in Los Angeles, JM Stibel, points out that the size of the human brain in modern people has decreased by more than five percent, compared to our ancestors.
– Changes in body size also seem to explain changes in brain size. With the exception of modern specimens, encephalization levels have remained fairly stable over the last 50,000 years. Although a modern brain sample has shown a relatively low level of encephalization, an increase in BMI (body mass index) appears to be responsible for the change in size, Stibel explains, adding that his research suggests that a relatively recent decrease in brain size is a response to changes in physiology. in relation to body weight and head size.
But he adds that there is strong evidence of a link between brain size and cognitive functions in humans.
– The lack of structural changes that have made the brain efficient and a significant reduction in brain size could lead to a decrease in cognitive functions – warns the author of the study.
The problem, Stibel points out, is that data from other studies show that, in addition to the evolutionary reduction in brain size, cognitive abilities are also reduced.
Namely, numerous researches have shown that during the 20th century, the average IQ of the population increased in industrialized countries. This is explained by better living conditions, education, technology development and environmental conditions. But the data from the last 30 years is not very encouraging.
In the most developed countries of the world, the level of IQ is falling, for which scientists cannot find a complete explanation.
– It is not clear whether physical changes in the brain or genetic predispositions can ultimately lead to a negative impact on a person’s cognitive abilities – Stibel notes at the end, adding that the movement of IQ should be additionally checked in the future, Zimo portal reported.
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