If you look at a Neanderthal skull and a Homo sapiens skull, they're visibly different: Neanderthal skulls are lower and longer, whereas ours tend to be rounder. However, those differences probably don’t say much about the brains within them, according to a recent study, which compared MRI scans of modern people’s brains with casts of the inside of Neanderthal skulls.
The results suggest that there’s more variation in brain size among modern people than between Neanderthals and Pleistocene Homo sapiens. And because brain size is actually a terrible way to predict cognitive capability, Neanderthals could have been a lot more like us than some previous studies have claimed, which definitely fits what the archaeological record tells us about how they lived. It would also mean that our species probably didn't out-compete the Neanderthals by being smarter or more adaptable.
Neanderthal brains fit within the modern human range
Years after you die, the inner vault of your skull will hold the shape of your brain; if future archaeologists make a cast of that inner space, they’ll get a neat resin model of the outer contours of your brain, called an endocast. (Sediment that filled the skull of an Australopithecus africanus child who died 2.8 million years ago did this naturally, creating an endocast that’s half rocky brain-sculpture and half sparkling crystal.) For years, researchers have studied endocasts of Neanderthal skulls, trying to piece together how their brains were different or similar to ours. And that has been a matter of some debate.
