The average height of early male humans was similar to that of Neanderthals, around 5'6" to 5'7". Both species had comparable brain sizes, but Neanderthals had a larger brain mass that was proportioned differently. Their brain structure favored memory, while early humans had a brain better suited for problem-solving. Neanderthals were generally shorter but heavier and more muscular than early human ancestors. Overall, despite some differences in physique and brain structure, the height and brain mass of both groups were quite similar.