As a neophyte in this subject matter (especially as compared to the vast majority of you) I really appreciate this article/blog. The explanation makes a lot of sense to this mature (not sayin' old) scientist. I had completely forgotten about the diagrams comparing the vertical forehead of us humans to the head of a gorilla (done by Bill Munns) and placed within the broader context of the piece as a whole, makes this helpful and interesting, at least to me. Thanks, Madison, for sharing it!