But size is not the whole story.

The shape of the Neanderthal brain differed from ours in ways that researchers have worked to interpret through endocasts — molds of the interior of the skull that preserve the rough outline of the brain’s surface.

Neanderthal brains were more elongated front to back, while modern human brains are more globular, with expanded parietal and temporal regions.

Those regions are associated, in modern humans, with functions including visuospatial integration, episodic memory, and aspects of symbolic thought.

What that difference in shape means for Neanderthal cognition is an active area of debate.