Neanderthal Brain Size Falls Within Modern Human Range, Challenging Notion of Cognitive Superiority

Context

When archaeologists compare Neanderthal and Homo sapiens skulls, the former appear lower and longer while ours are rounder. Those external differences do not directly reveal brain structure, so researchers rely on endocasts—natural or resin casts of the inner skull—to infer brain shape and size.

Key Facts

A 2018 study led by researchers at the Max Planck Institute for Evolutionary Anthropology and published in the *Journal of Human Evolution* examined endocasts from four Neanderthals and four early Homo sapiens. Using MRI scans of modern human brains as a reference, the team measured the volumes of 13 major brain regions in each cast. They found that modern humans exhibit a brain‑size spread of roughly 150 cubic centimeters, whereas the average difference between Neanderthals and early Homo sapiens is under 50 cubic centimeters. Although Neanderthals had larger overall skulls, their cerebellums were on average about 8% smaller than those of Homo sapiens, a region linked to motor control, attention, and emotional regulation.

What It Means

Because brain size alone is a poor predictor of cognitive ability, the overlap in brain‑size ranges suggests Neanderthals may have possessed cognitive capacities comparable to early modern humans. This challenges older ideas that Homo sapiens out‑competed Neanderthals through superior intelligence. Future work will focus on refining regional brain‑size estimates with larger fossil samples and exploring cerebellar function through comparative neuroanatomy.

Watch for upcoming studies that integrate genetic data with endocast analysis to clarify how brain organization, not just size, influenced Neanderthal behavior.