Shrinking Brain in Humans

Scientists are alarmed by shrinking of the human brain


A study published earlier this year confirmed what scientists have long believed to be the case – the human brain is shrinking.  For more than 7 million years the hominid brain has grown increasingly bigger, almost tripling in size.  But for the last 10,000 years, the human brain has been shrinking at an alarming rate and no one really knows why. New research has attempted to answer this question by examining size changes in specific regions of the brain.

The study published in the American Journal of Physical Anthropology was carried out by a team of Chinese researchers who looked at over 500 endocasts from the past 7,000 years. Endocasts are moulds of brains created from the imprints on the inside of the skull. They are an invaluable resource when studying human evolution, allowing us to track how our brain has evolved over the past few million years.  The results confirmed what has long been suspected – our brains are getting smaller.


It was in 2010 when researching a skull that belonged to a Cro Magnon man that scientists first discovered the brain of our ancient ancestor was significantly larger than humans today. This has been replicated time and again and it can now be said that the human brain has decreased from 1,500 cubic centimetres (cc) to 1,350cc, irrespective of gender and race.  If we continue on this path, we will end up having the same-sized brain as Homo Erectus, an ancient human species which had a brain of 1,100 cc.

Does a smaller brain mean less intelligence?

Scientists have been debating for many years about whether a smaller brain means less intelligence, and no agreement has been reached.  To clarify, it is not simply the size of the brain that is relevant here, but the size of the brain in relation to body size, referred to as the Encephalization Quotient (EQ).  Research has found a close relationship between intelligence and EQ. 

Over millions of years, the hominid body has been shrinking but the worrying fact is that our brains are shrinking faster than our bodies. Does this mean human beings are getting dumber, or are smaller brains not necessarily bad?

The human brain is shrinking faster than the shrinkage of the body

The human brain is shrinking faster than the shrinkage of the body. Image credit:

Many scientists have argued that bigger doesn’t always mean better.  Duke University anthropologist Brian Hare says "the decrease in brain size is actually an evolutionary advantage" because it could indicate we're evolving into a less aggressive animal. For example, the common chimpanzees have bigger brains than bonobos, but they are less likely to resolve issues through teamwork because they're more aggressive. 

Other proponents of the ‘bigger isn’t better’ hypothesis have argued that our ancestors had a larger visual cortex because good vision was necessary for survival. But as social support increased, vision became less important. Those with smaller visual cortexes had more resources available for social regions of the brain, thus increasing chances of survival.

However, the findings of the new study conducted in China are not consistent with these theories because the results indicated that it was not one particular area of the brain that was shrinking – the whole brain has been getting smaller. If the hypothesis about the visual cortex was correct, we should see shrinkage only in that region of the brain.

The one exception is the frontal lobe, which actually seems to be increasing in size. The frontal lobe is the region of the brain responsible for speaking, comprehending the speech of others, reading and writing. It is possible that we are doing a lot more of that now – at least the reading and writing part – compared to our ancient past.

While plenty of hypotheses have been put forward to justify the shrinking of the human brain, there remain many who are less optimistic. The authors of a study published in 2012 maintained that humans lost the evolutionary pressure to be smart once they formed agricultural settlements. 

"A hunter-gatherer who did not correctly conceive a solution to providing food or shelter probably died, along with his/her progeny, whereas a modern Wall Street executive that made a similar conceptual mistake would receive a substantial bonus and be a more attractive mate. Clearly, extreme selection is a thing of the past," the researchers wrote in the journal article published in the journal Trends in Genetics.

More than 4,000 years ago, great civilizations existed around the world and the ancient inhabitants built incredible buildings and cities with great precision and beauty, often with astronomical alignments that we are only just beginning to realise. Nowadays, technology has taken over, rendering our need to apply skill, creativity, and memory virtually redundant. Instead of memorising navigational routes we switch on our ‘sat navs’ and rather than storing phone numbers and addresses in our memory banks, we have them all to hand on our iPhones and Blackberries.  Our technology is evolving rapidly, but sadly it seems that we are not.

By April Holloway


Peter Harrap's picture

Observe how creatures with small brains do things we are unable to do. Birds fly, bees fly, even though theoretically OUR brainy scientists say they should not be able to! There are insects with dozens of legs, their brains can separately control-think about it!- and creatures who have more sense faculties than us. Can you see a mouse from a mile up in the sky!?

So the idea from our brains that the size of our brains matters is somewhat dickheaded, if you’ll pardon my French, or is it Bulgarian?


Dont you just love reading how creative some of these comments are, such as Aliya's? So free thinking is still very much alive and well despite some of the comments to the contrary.

Once upon a time Earth gravitation was smaller than it is now due to the young age of our planet earth and its higher electric and geomagnetic charge within. Everything was easier than it appears to us now - the walking of the people our ancestors the giants, the stone constructions like the pyramids and the circle sanctuaries built everywhere around the planet.
Even the life of the giants was longer than ours due to the smaller earth gravitation. Our ancestors the Nephilims were granted by their God Father Ra with long life (900 -1000 years) as it is narrated in the Bible.
Our ancestors were very wise enlightened people and they had their intuition and inner senses much more developped than we have them today.
If you want to immagine how life of our ancestors was once upon a time you better see once again the film Avatar. Our ancestors had big and very well developed beautiful bodies, smaller heads and intuitive wisdom of no comparison nowadays.
The changing Earth gravitation is the reason for the cranial trepanation, cranial deformation, blood letting medical practices of the ancient Bulgarians who spread all over the globe after the Bibical flood in Black Sea in around 5500 BC. Ancient ancestors had to coope with the changing earth conditions as well. They are humans with some slight diferences from the today human cranes - instead of three plates on top they had two plates. And this peculiarity has an explanation - they were giants, nephilims and their heads were easier to be born by a giant mother as it is today for mothers to give birth. You remember what the Bible says: after Adam and Eve were thrown out of the paradise woman was sentenced by God to give birth with difficulty.
That explains also why our giant ancestors had to build pyramids and to dig holes in the mountain rocks on special geomagnetic spots on Earth. They used to do that for milenia in Bulgarian mountains as well - our country is famous with its ancient miraculous mountains and their sanctuaries. On these holy spots Ancient Bulgarians used to perform spiritual rituals today called Mysteries and to energise their bodies & minds with the earth geomagnetism.

That's why it's called a "theory."

"psychedelic mushrooms." can increase neurogenesis in hippocampus ("Effects of psilocybin on hippocampal neurogenesis and extinction of trace fear conditioning") like cannabis exersise and many other things. They phased out of our diet cant be significant cause of smaller brain because there are manny substitutes its effects.P.S His theory say mostly that shrooms cause development of language not intelligence per se "The real impact did come at higher doses, according to McKenna’s theory, because it was at the higher doses that man was inspired to use sound to put images into another’s head. Language development saw immense growth during this period, and the Stoned Ape Theory insinuates experiences on mushrooms helped further this development along" He has also other theory
"McKenna theorizes intelligence might have made its way to our planet via spore-bearing intelligent life that traveled to Earth in cosmic radiation, much like what is described in the Crick Theory of Panspermia." So please dont spread misinformation about author who clearly state that this is only assumption nothing else.


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