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Human Brain Shape Hardly Changed in 160,000 Years

Faces changed, yes, and researchers think diet may have played a role

The changes in human heads over the past 160,000 years were not driven by a changing brain, researchers say. It was the human face that changed, according to a recent article at New Scientist:

Comparing the braincases of early modern human children with adults for the first time allowed the researchers to isolate the brain’s role in the evolution of the skull. The team was surprised to find that while the size and proportions of the skulls of H. sapiens children from 160,000 years ago were largely comparable to children today, the adults looked remarkably different to those of modern adults, with much longer faces and more pronounced features.

Human faces continue to grow until the age of around 20, but the brain reaches around 95 per cent of its adult size by age 6.

Luke Taylor, “Shape of human brain has barely changed in past 160,000 years” at New Scientist (August 1, 2022) The paper is open access.
MRI or magnetic resonance image of head and brain scan. Close up view

Curiously, age 7 is widely considered to be the age of reason, the point at which a child can clearly understand concepts like right and wrong, as well as the difference between reality and make-believe. In any event, the researchers suggest that the change in human faces over time could stem from a different diet (less chewing) or less need for oxygen.

During the same time period — one of spectacular intellectual achievements — human brains shrank in size.

That said, we are always discovering new things about the human brain. Here are three interesting ones to ponder:

What’s inside the brain is immense

“Processing so many kinds of information requires many types of neurons; there may be as many as 10,000 types of them. Processing so much information requires a lot of neurons. How many? Well, “best estimates” indicate that there are around 200 billion neurons in the brain alone! And as each of these neurons is connected to between 5,000 and 200,000 other neurons, the number of ways that information flows among neurons in the brain is so large, it is greater than the number stars in the entire universe!” – The Mind Project

The human brain is said to be the most complex organized thing in the universe and to be similar in organization.

Do you know how many thoughts you have per minute?

One research group tried to work it out: “The average person has about 48.6 thoughts per minute, according to the Laboratory of Neuro Imaging at the University of Southern California. That adds up to a total of 70,000 thoughts per day.” – Reference.com In light of the numbers, we should all hope that not too many of our thoughts were obsessing about stuff that doesn’t really matter.

Health advice your brain will be happy with

From Healthline: “About 75 percent of the brain is made up of water. This means that dehydration, even in small amounts, can have a negative effect on the brain functions.” From Northwestern Medicine: “Sixty percent of the human brain is made of fat. Not only does that make it the fattiest organ in the human body, but these fatty acids are crucial for your brain’s performance. Make sure you’re fueling it appropriately with healthy, brain-boosting nutrients.” (Coffee and chocolate are included). And, from The Healthy: “Exercise is just as good for your brain as it is for your body … Especially when you try a new fitness class or regimen for the first time, your brain is working hard at learning the motions and controlling your muscles. ” Six ways that exercise benefits your brain are offered.

You may also wish to read: Researchers still puzzled: Why did human brains shrink? Human brain volumes decreased by 10% in the last 40,000 years, coinciding with spectacular intellectual achievements. Examples of brain shrinkage among animals are fascinating but have not provided much insight. But perhaps we should ask, how much does brain size even matter?

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Human Brain Shape Hardly Changed in 160,000 Years