Modern humans are indistinguishable from those early hunter-gather tribes 40,000 years ago in Africa
I think
There's no way you can be certain of this, as your "I think" acknowledges. Besides, even if biologically we are identical, millennia of civilization, however imperfect, have influenced the way we think. Reason can triumph over impulse. Sadly, it can also be put to its service.
I do like that you cite INXS as your authority, though.
By the way, I've now almost finished listening to
I Am Legend (a straight reading of the book, not a dramatization), and after three years Robert Neville's sex drive has become dormant.
P.S. While by no means perfect,
The Last Man on Earth is far truer to the book than either of the other film adaptations.