The functioning of the human brain changed with the appearance of Homo erectus roughly 1.7 mya. This marked a bifurcation in the procession of brain development whereby cognitive capacities began to develop at ever accelerating rate. It marked the advent of humans using fire, the transition from the older Olduwan tool technology to the then-modern Auchelain technology, to the use of clothing, the loss of body hair, and an entire panoply of changes that really made us human. What do you guys think precipitated that?
