19 JUL 2013 by ideonexus

 Hand Axes as an Extended Phenotype

Two and a half million years ago, our small-brained ancestors evolved the ability to knock flakes from rocks to use as cutting edges. By doing so, they could also make the rocks themselves useful as choppers. This basic tool kit of flakes and choppers served the needs of hunting and gathering for a million years. Then, around 1.6 million years ago, a medium-brained African hominid (Homo erectus) evolved the ability to produce an extraordinary object that archeologists call a handaxe. A handax...
  1  notes

If, as the author assumes, handaxes were genetically-informed because they did not change for hundreds of thousands of years, then why do we not still have the instinct for hand axes?