It may just have to do with the expansion of common intelligence in early human societies.

Our brains have gone through several growth spurts in the distant past. But about 3000 years ago, something remarkable happened. Instead of our brain getting bigger again, it actually decreased in size. Researchers have in a new study attempted to explain this mysterious shrinkage of the human brain. And we succeeded, thanks to a little help from ants.

Brain

The brain is the most complex organ in the human body. Scientists are therefore very interested in studying it. Because it may help us to better understand the nature of humanity.

brain boost

As mentioned, the human brain is known to grow throughout our evolutionary history. “Most people are aware that we have unusually large brains,” said study researcher James Traniello. “Significantly bigger than you might think based on our body size.” This increase can be explained in itself. This coincides with our early evolution and the technical progress that led to, for example, better nutrition and larger social groups.

Brain Reduction

But that growth suddenly came to an end about 3000 years ago, at the time of the Pleistocene. “A surprising fact about humans today is that our brains are smaller compared to the brains of our Pleistocene ancestors,” said study researcher Jeremy DeSilva. “Why our brains have shrunk is a great mystery.” But maybe ants can put us on the right track, the researchers thought. “Understanding why brain size increases or decreases is difficult to study using fossils alone,” explains Traniello. “We started sharing thoughts about brain evolution and discovered bridges between humans and ants.”

ants

That may surprise you. The societies of humans and ants are very different. “At the same time, ants also share important aspects of social life with humans,” Traniello says. “Think, for example, of matters such as group decision-making, division of labor and the production of one’s own food (agriculture). And these similarities could broadly tell us more about the factors that can influence changes in the size of the human brain.”

Study

In the study, the researchers studied the brain size, structure and energy expenditure of several types of worker ants, including the green weaver ant, Atta and the large pangolins. And that leads to an interesting discovery. Ant brains appear to have been modified, allowing knowledge to be shared efficiently in social groups on the one hand, and certain ants becoming specialists in specific tasks on the other. And part of this efficiency is a smaller brain.

Declaration

It leads to an interesting explanation for the mysterious shrinkage of our own brains. The brain uses a lot of energy. But a smaller brain uses less energy, which is of course more beneficial. And at some point in our human history, when we started to live more in groups, it was no longer necessary to store a lot of information in a single head. According to the researchers, this could just be the reason for the decrease in our brain size. “We propose that the decline is due to the expansion of common intelligence,” clarified Traniello. “The idea that a group of people is smarter than the smartest person in the group is often referred to as ‘the wisdom of the crowd’.”

While it’s an interesting theory, it hasn’t actually been proven yet. Follow-up research is already underway. “We look forward to testing our hypothesis as additional data becomes available,” concludes DeSilva.