2021-10-22

Scientists have found new clues that the human brain became smaller 3000 years ago

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1b0f3ecaf9adaad - Scientists have found new clues that the human brain became smaller 3000 years ago

“a surprising fact of human beings today is that our brains are smaller than those of our newer ancestors.” Jeremy deSilva, co-author of the paper from Dartmouth College, said, “why our brain has shrunk is a big mystery for anthropologists.”

in order to solve this mystery, a team of researchers from different academic fields began to study the historical model of human brain evolution, Compare their findings with what is known in ant society to provide broad insights

“a biological anthropologist and a behavioral ecologist and evolutionary neurobiologist began to share their ideas on brain evolution and found that bridging the research on humans and ants may help to determine the possibilities of nature,” said Dr. James traniello of Boston University, co-author of the research paper

the researchers analyzed the data sets of 985 fossils and modern human skulls. As a result, they found that the volume of the human brain increased during the Pleistocene 2.1 million years ago and 1.5 million years ago, but decreased about 3000 years ago (Holocene), which was later than previous estimates

“most people know that humans have unusually large brains – significantly larger than predicted from our body size. In our deep evolutionary history, human brain size has increased sharply,” traniello said. “The reduction in human brain size 3000 years ago was unexpected.”

the time of size increase is consistent with the previously known early evolution and technological progress of Homo sapiens, such as leading to better diet and nutrition and larger social groups

as for the reduction of brain size, this interdisciplinary research team put forward a new hypothesis and looked for clues in ant society

what can ants bring us about the evolution of human brain

“we propose that ants can provide diverse models to understand why the brain may increase or decrease due to social life. Understanding why the brain increases or decreases is difficult to study only with fossils,” traniello said

by studying the computational models and patterns of brain size, structure and energy use of worker ants in some ant branches, researchers found that cognition and division of labor at the group level may choose adaptive brain size changes. This means that in a knowledge sharing society or an individual is an expert on some tasks, the brain may adapt and become more efficient, such as reducing size

“ants and human society are very different and take different routes in social evolution,” traniello said. “Nevertheless, ants also share important aspects of social life with humans, such as group decision-making and division of labor, as well as producing their own food (Agriculture) These similarities can broadly tell us the factors that may affect the size change of human brain. ”

the brain consumes a lot of energy, while smaller brains use less energy. Because of the externalization of knowledge in human society, less energy is needed to store a large amount of information, which may be conducive to the reduction of brain size as an individual

“we propose that this decrease is due to the increased dependence on collective wisdom, that is, the idea that a group of people are smarter than the smartest people in the group, which is often called’the wisdom of the masses’,” traniello said

deSilva concluded: “we look forward to testing our hypothesis as more data appear.”