Posted on 10/22/2021 9:28:10 AM PDT by Red Badger
When and why did human brains decrease in size 3,000 years ago? New study may have found clues within ants.
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The brain is the most complex organ in the human body. Now, a new study has brought us closer to understanding some of its evolution. It shows that human brains decreased in size approximately 3,000 years ago. By studying ants as models to illustrate why brains may increase or decrease in size, the researchers hypothesize that brain shrinkage parallels the expansion of collective intelligence in human societies.
Studying and understanding the causes and consequences of brain evolution helps us understand the nature of humanity. It is well documented that human brains have increased in size over the course of our evolutionary history. Less appreciated is the fact that human brains have decreased in size since the Pleistocene. When exactly these changes happened, or why, was not well known.
“A surprising fact about humans today is that our brains are smaller compared to the brains of our Pleistocene ancestors. Why our brains have reduced in size has been a big mystery for anthropologists,” explained co-author Dr. Jeremy DeSilva, from Dartmouth College.
To disentangle this mystery, a team of researchers from different academic fields set out to study the historical patterns of human brain evolution, comparing their findings with what is known in ant societies to offer broad insights.
“A biological anthropologist and a behavioral ecologist and evolutionary neurobiologist began sharing their thoughts on brain evolution and found bridging research on humans and ants might help identify what is possible in nature,” said co-author Dr. James Traniello, from Boston University.
Their paper, published in Frontiers in Ecology and Evolution, sheds new light on the evolution of our brain.
A recent size decrease The researchers applied a change-point analysis to a dataset of 985 fossil and modern human crania. They found that human brains increased in size 2.1m years ago and 1.5m years ago, during the Pleistocene, but decreased in size around 3,000 years ago (Holocene), which is more recent than previous estimates.
“Most people are aware that humans have unusually large brains – significantly larger than predicted from our body size. In our deep evolutionary history, human brain size dramatically increased,” said Traniello. “The reduction in human brain size 3,000 years ago was unexpected.”
The timing of size increase coincides with what is previously known about the early evolution of Homo and the technical advancements that led to, for example, better diet and nutrition and larger social groups.
As for the decrease in brain size, the interdisciplinary team of researchers propose a new hypothesis, finding clues within ant societies.
What could ants teach us about human brain evolution? “We propose that ants can provide diverse models to understand why brains may increase or decrease in size due to social life. Understanding why brains increase or decrease is difficult to study using only fossils,” explained Traniello.
Studying computational models and patterns of worker ant brain size, structure, and energy use in some ant clades, such as the Oecophylla weaver ant, Atta leafcutter ants, or the common garden ant Formica, showed that group-level cognition and division of labor may select for adaptive brain size variation. This means that within a social group where knowledge is shared or individuals are specialists at certain tasks, brains may adapt to become more efficient, such as decreasing in size.
“Ant and human societies are very different and have taken different routes in social evolution,” Traniello said. “Nevertheless, ants also share with humans important aspects of social life such as group decision-making and division of labor, as well as the production of their own food (agriculture). These similarities can broadly inform us of the factors that may influence changes in human brain size.”
Brains use up a lot of energy, and smaller brains use less energy. The externalization of knowledge in human societies, thus needing less energy to store a lot of information as individuals, may have favored a decrease in brain size.
“We propose that this decrease was due to increased reliance on collective intelligence, the idea that a group of people is smarter than the smartest person in the group, often called the ‘wisdom of the crowds’”, added Traniello.
DeSilva concluded:
“We look forward to having our hypothesis tested as additional data become available.”
Reference: 22 October 2021, Frontiers in Ecology and Evolution.
DOI: 10.3389/fevo.2021.742639
Reverse evolution: Atrophy that which is not used or necessary for survival.................
In the year 2525...............................
Learning to do more , .. with less brain size
It's what Socialism teaches us !
True.....................
beer goes back some 4500 years in Iran, etc.
the reason brains shrunk was the founding of the Demo party
Beer is the reason for civilization.
So maybe civilization or a more sedentary lifestyle caused it.
.....OUR FUTURE?......................
To sum it up, civilization will eventually render the great mass of humanity into mindless drones.
Beer, bacon and beans?
Pork, potatos and pudding?
Or Moore’s law?
Now I’m hungry.
5.56mm
It took 1500 years to have a societal effect................
We are damn near there now....................
ok
but frankly alcoholic beverages have impact on me much faster than that
Agriculture is what made our brains shrunk. When you can stay in one place and provide for yourself, you don’t need to remember topography or weather patterns like you do as a nomadic hunter.
Quality vs quantity
Maybe our modern brains are fabricated using a more highly advanced, yet smaller brain cells. Similar to developments in integrated circuits.
Your post #27 and photo
I think I saw him in "BeetleJuice", the movie.
Agriculture is what made our brains shrunk. When you can stay in one place and provide for yourself, you don’t need to remember topography or weather patterns like you do as a nomadic hunter.
~~~
Yes, not that agriculture itself didn’t make people dumb, but the more consistent availability of calories allow for specialization and trades. In essence “civilization” as we know it is about collective specialization. You give up jack-of-all-trades for laborers, artisans and professionals. They still need to use their cerebral cortex, but once they have their jobs down pat, I’m going to bet their EEG readings flatten out a lot.
“The premise of this hypothesis is very intriguing. “
It has been around for a long time. For a fun read, look up C.M. Kornbluth’s The Marching Morons, a short story from 1959. It is the precursor to the movie, Idocracy. The logic of both is inescapable.
Liberals on welfare, free medical care, food stamps, lodging, watching ABCNNBCBS and being told, and who to vote for, don’t really need a big brain.
Their some what elected Resident even tells them when to get vaccinated, and who to hate.
Having a brain big enough to protest what your child is or isn’t being taught at public school is now a dangerous terrorist activity as per our AG!.
Then, regular daily drug use shrinks their unused brains even more each day.
So liberals don’t need a normal IQ or big brain.
So liberals have been around for a while now. Who knew?
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