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


Why should we worry? Humans adopt, just like animals, so maybe shrinking what we don't nee everyday and vv, is a normal process. 

Just look around in a bus in the early mornings. All those bent heads apping away like crazy, checking facebook.  Just try and see how many of the younger generation don't think an original thought all day. Too much work.  I'm a teacher I should know.

They don't need to think, they function on automatic pilot, there's no need to think. 

Also for most of us there is  no need to be alert all day, life is easy and safe. 

So  brain parts shrink.

Wen needed over a long period of time, the necessary parts will grow again.


Sunny Young

Brain is Shrinking due to Domestication of Brain.

Read this article one more time on with coments think about what you've read and then post comments. Size Matters: Scientists Prove People With Big Heads Are Smarter ~- "brain size has to do with the size of the organism. This is stupid, Especially when he says things like " unequivocal proof " followed by "couldn't review enough brain scans to obtain definitive results" ... yeah no kidding, cuz there is a vast amount of evidence that correlates brain size to body size. It's observable in mammals and you can trace it archaeologically looking at hominin evolution. A huge portion of your brain runs autonomic functions" Whats more there is this one flawed study against many which claim opposite.

Size Matters: Scientists Prove People With Big Heads Are Smarter ~
The science on big heads is out, and size matters. Big heads lead to big developed brains in the cranial cavity that equate to more often than not, Secrets of the Pyramid Brain Image1 Size Matters : Scientists Prove People With Big Heads Are Smartera higher intelligence. This does not mean that all people who have a large head are very smart or that the smaller your head and smaller you brain, the less intelligent you are. Please keep in mind that there are exceptions to this rule as there are with almost all rules of life. But the scientific facts are that brain size is a factor in how smart an animal or mammal is, and if people with big heads are able to tap more of that brain matter than that of their smaller headed cousins, then they can become more intelligent.

Specific Genes Linked to Big Brains and Intelligence

Brain size and smarts are, to some extent, genetic — and now, a team of more than 200 researchers has uncovered specific genes that are linked to both brain volume and IQ.

Though scientists have suggested bigger brains are “smarter,” this study is the strongest case yet for a genetic connection to brain size and to IQ. Of course, brain size is not 100 percent correlated with a person’s intelligence, and other factors, including connections between brain cells and even a person’s experiences play a role.

“We found fairly unequivocal proof supporting a genetic link to brain function and intelligence. For the first time, we have watertight evidence of how these genes affect the brain,” said lead researcher Paul Thompson, a neurologist at the University of California, Los Angeles, School of Medicine.

I always have wondered if my gigantic head could be a genetic physical trait passed to me from my ancestors, and now I think my intuition has led me to the light.When I say my head is gigantic, I really mean it, in which it has caused me some problems while I was growing up. From being a top head heavy kid- who has actually cracked open his skull numerous times, to never having helmets fit my head correctly, and to currently having to buy my hats from

What I had thought was some sort of birth defect is actually a genetic trait passed down to me by my ancestors. For example: A relative of mine Charles Joseph Bonaparte, the grandnephew of Napoleon who first organized the “detective force of special agents” of the Department of Justice- now known as G-men, who was also Secretary of the Navy and later, Attorney General in the cabinet of Theodore Roosevelt. Charles Bonaparte was described as “A vast round, rugged head; a double-decker head; a cannon ball head, like a warrior’s, with room for two sets of brains, bald and shiny.” His hair and eyes were jet black, his hands and feet small. He had the clear ruddy complexion of an outdoorsman. He constantly wore black, carried an umbrella – not a cane – and looked like a “studious professor.” He did much of his thinking on the street, striding briskly along, his massive head-“with curious rises over the temples”-swaying from side to side.


However, the findings of the new study conducted in China are not consistent with these theories because the results indicated that it was not.... and why with first theory this is not consistent ? they dont say about about part but all brain. "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"

What more there was some study in 2011 we have shrunk brain indeed but have better conectivity. The authors of a study published in 2012 maintained t - link you give here denies " Instead, removing the pressure for everyone to be a superb hunter or gatherer may have allowed us to evolve a more diverse population with different types of smarts, he said."


Next article