The information is detailed in a study by evolutionary scientist John Hawks. Since the Stone Age, there have been many changes in the human body, most of which are unsurprising. But the revelation that our brains are actually smaller now than they were then could strike some as shocking.
Hawks says over the last 20,000 years, the average male brain has shrunk from 1,500 cubic centimeters to 1,350 cubic centimeters. That’s a chunk about the size of a tennis ball. Hawks also says the same has happened to the female brain, and isn’t limited to any region in the world. There’s little incentive to think we’re getting dumber, though. Brain size, generally speaking, isn’t an accurate indicator of intelligence.
So the big question is why? There is a series of theories about the subject. While some do argue the shrinking of gray matter means we’re getting dumber, others contend that our brains are shrinking because they’re becoming more efficient. If that doesn’t make sense, think of it like new iterations of certain kinds technology that grow smaller with each generation but also more advanced and more powerful.
The most obvious example is probably the ever-thinning various smartphones. Still, many aren’t aware of this, or consider it an insignificant detail. You can read more on the report at the source.