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.
Berdasarkan analisisnya terhadap hubungan antara ukuran otak dan besar kelompok hominid, dia menyimpulkan bahwa karena manusia purba memiliki otak yang besar, mereka pastilah hidup di dalam satu kelompok yang lebih dari 120 individu.