New research suggests that due to global warming, human brains are getting smaller. The brain volume is decreasing by 10%, which is equivalent to the size of four ping pong balls.
Key points of this article that can be understood in 3 lines
- According to research, the human brain has become 10% smaller since the Ice Age. This could be because of climate stress. It might affect intelligence overall.
- Brain size does not affect IQ, but Americans’ IQ scores have been decreasing according to recent studies.
- Modern technology like smartphones and AI might be responsible for the decrease in mental effort.
Jeff Morgan Stibel, a smart person at the California Museum, wrote an article in July about how climate change affects brain size. The article was published in the Brain, Behavior, and Evolution journal. It talks about how the two things are related.
The team checked 298 old human skulls found within 50,000 years. They took 373 precise volume measurements and discovered that after the last Ice Age, the human brain started to shrink. Since then, it has shrunk by 10%.
The study compared brain volume during warm and cold periods. It found that climate stress caused the decrease in brain volume. Global warming was the main factor, followed by humidity and precipitation.
Have you heard of the concept of 10%? It means a reduction. For example, the average brain volume of modern humans is around 1200-1400ml. If we have a 10% decrease, it means we lose a brain the size of 4 ping-pong balls.
Humans may be affected by the loss of animal brains. Will it cause a decline in human IQ points?
When the brain volume increased four times and then decreased by 10%, what occurred?
Human brains have increased in size throughout our history.
Shah Homo from Chad is the earliest Hominini, appearing 7 million years ago. Their skulls were small with a brain capacity of 350ml, according to fossils.
The first two-legged ape, Australopithecus apes, lived over 3 million years ago. They had a brain size of 500ml.
Scientists think that humans‘ brain size grew as they started living in groups. This kind of living led to bigger brains in later humans.
Over 2 million years ago, Homo habilis had a brain that was about 550-687 ml. When it evolved into Homo erectus, which lived between 1.9 million to 27,000 years ago, the brain size increased to over 1,000 and sometimes up to 1,250 ml.
During Homo sapiens time, brain capacity reached 1,400 ml. Neanderthal man, hundreds of thousands of years ago, had the largest brain capacity of 1,680 ml.
The human brain has grown from 350ml to 1680ml, which is four times the original size. The average brain capacity can reach 1500ml.
Does that mean that our human brains will develop linearly and continue to grow?
Contrary to popular belief, the brain capacity of modern people is not as large as it used to be. I studied the brain capacity of modern people and found that on average, it is now 1350ml. This is a significant decline from the peak brain capacity of 1500ml, where it has decreased by 150ml. To put this in context, this volume is similar to four table tennis balls or a single tennis ball.
Let’s first take a look at why the brain gets bigger?
Evolutionary scientists think that three things make human brains bigger: environment, people, and culture. These three things work together to make brains grow.
Humans live in groups and face challenges like finding food, hunting, and avoiding danger. These challenges put pressure on the brain to grow larger.
People need to work together and sometimes compete, which can help develop bigger brains.
Animals in nature live in groups too, but they don’t have smarter brains. This means culture is important for human brain changes. The ability to learn and teach others is crucial for this process.
Scientists believe that brain shrinkage is actually related to living in groups.
Swarm intelligence lets a group work well without each person needing many skills. If the team works right, some parts of the brain may not be needed anymore and could weaken over time.
The brain shrinks and the IQ decreases
There is no direct connection between brain size and IQ, but a study shows that year by year, Americans’ IQs are decreasing.
Like brain capacity, IQ also experienced rapid increases and then decreases.
Human IQ results have been increasing yearly since the IQ test was developed. This is known as the Flynn effect. The test was created in the 1970s by New Zealand scholar James Flynn.
In the US, Flynn and team discovered that the IQ average was 70 points in 1990. But by 2000, it had gone up to 100 points. Over the last century, IQ has grown by 30 points, roughly 3 points per decade.
A man thinks that our IQ can be better if we live in a nice place. A good education, food, and healthcare make us smart.
New research suggests that the Flynn Effect is stopping and reversing. Experts previously believed this trend would continue.
A study was conducted on the test results of around 400,000 American adults between 2006 and 2018. It showed that over those 12 years, IQ fell by 2 points in three domains except for spatial reasoning, which increased.
Several countries, including the United States, Finland, France, the United Kingdom, Norway, Denmark, Australia, the Netherlands and Sweden have made similar discoveries recently.
According to existing research, in Finland, IQ scores dropped by 2% from 1997 to 2009; in France, IQ scores dropped by 4% from 1999 to 2009.
The reason for the fall in IQ scores is that people have become lazy in thinking, according to researchers.
Everything is easier now than before because of modern technology. Smartphones, artificial intelligence, and social media are some examples. These tools replace many functions of the human brain. Calculators perform calculations, and listening replaces reading. If you have questions, you don’t need to remember anything because you can search for answers with just one click on your smartphone.
Over time, the brain becomes lazy due to these factors. This makes it work less harder than before.
In general, big brain doesn’t always equal high intelligence. Having a large brain only increases the possibility of being intelligent, but it’s not guaranteed.
Intelligence is not linked to IQ scores. These tests only measure specific skills and do not reflect overall intelligence. A low score does not mean you are unintelligent.
Currently, IQ scores in many developed countries are going down. This is a concern and we need to pay attention to it. Technology could be having an impact on our intelligence.
Technology has improved our lives, but it has also caused some problems.
If I use my phone a lot, I sometimes forget how to write. I watch videos more than reading. Is this good or bad?
In the future, we may become “Future Man Mindy”. Scientists are creating an image of this possibility. This may seem scary, but it’s not impossible.