Based on his analysis of the relationship between brain size and hominin group size, he concluded that because archaic humans had large brains, they must have lived in groups of over 120 individuals.
Baseándose na análise das relacións entre o tamaño da masa encefálica e o tamaño do grupo de homínidos, conclúe que os humanos arcaicos tiñan cerebros amplos xa que tiñan que convivir en grupos de ata 120 individuos.