Shrinking Brain in Humans

Scientists are alarmed by shrinking of the human brain

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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: Superscholar.org

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.

Comments

I agree with you our brain is very plastic there are even few case where people have 70% damage from stroke and their brain reorganize and create connection which allow them function normally. What expierience you give brain so you will had a brain. "Film, Television" I will say that contents cause effect there can be highly stimulating programs on tv and I see recently study which shows some benefits to brain from wathing tv. But also dumg programs can be beneficial because our brains must sometimes rest and with little stimulated programs have good opportunity(there are some studies showing correlation with overworking brain and neurodegenerative diseases) We can conclude that average people are less inteligent but this is due to increased borns in families with lower inteligence. Many video games gets attention among rehabilitants. SO as I say contents not device cause stimulation to brain and this organs can adapt to virtualy all situation.

The powers that be are shrinking our brains by giving it less to feed on.  Film, Television, and the rubbish we are fed, tend to dumb us down, and it is working well.  

The human brain has great potential, but if we keep being fed rubbish, we will eventually loose whatever potential we have.

We are not even capable of making good decisitons about our earth.  Instead, we are fed rubbish.

It is time to take back control again, and use our brains in more demanding areas.

Glee

johnblack's picture

Very good points :-)

P.S about We use glasses instead of exercizing our eyes" many refractive errors are due to shape of cornea not muscle only some of them are from using near subject but only small % of all refractive errors. that why you exercise cant do anything and glasses dont cause that your vision will detorate look at studies which research that.

Of course, in a situation like that, we are bound to lose intelligence as much we lose muscle when we don't use it. only you some how lose intelligence, because we have smaller brain with increased intelligence. Your statments We... only show your lack of knowledge.
"We use glasses instead of exercizing our eyes" many refractive errors are due to shape of cornea not muscle only some of them are from using near subject but only small % of all refractive errors.
"We use artificial light instead " from when people use artificial light when fire was invented.
"We use calculators instead of calculating ourselves." again since abacus was invented
"We use maps instead of measuring distances with our eyes and feet" I dont even know how comment this you use map to measuring distances? I use to find location.
"We are far removed from our food and water, it is processed, genetically altered, filled with antibiotics, poisons, products we don't even know enough about." here is true you really " don't even know enough about" but dont think that others also. When you wrote about something read about that firs antibiotics animals are slaughteredafter they detox antibiotics so you will get very low amount iif any. poisons- first rule of toxicology the dose make poison, and lower dose can be beneficial read about hormesis also you think that something natural cannot be toxic in proper dose? look at bella donna and others herbs shrooms etc. "We are far removed from our food and water" read about how many people was poisoned by water in ancient times compared to our times this called by you poisons protect you against this bacterias. "We don't care about the geometry of our houses, offices, temples, as long as it fits our immediate needs, it's fine."you get evil spirit from that....what does this have to do with our brains? "We take medication for everything instead of figuring out the source of our problems" people treat thersefl by herbs which are also medication look at traditional chinese medicine from how long they use herbs to heal. "We are constantly compensating, letting the world change or suffer so that we cease to change and suffer. Of course, in a situation like that, we are bound to lose intelligence as much we lose muscle when we don't use it." the biggest stupidity I read in this month. So compared to you people wich customize environment to their need use magic no inteligence? Thats why our inteligence increase because we use our brains to change world for us, so we use more brains than in past ours body dont evolve because our brains do creating world for us, and smallest brain means that have better connection and can work more effective. Of course you most likely dont use your brain (your comment show that) so you are at risk to lose him. In conclusion you want to show some intelligence but turned out you only shows your incompetence.

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