This incongruity gives rise to the perennial question: Are humans naturally good or evil?
In the introduction of the book, Wrangham provides his answer: both.
and
Ever since the Enlightenment, as religion gradually fell by the wayside, people have been trying to ground their moral compasses in another prestigious entity—science. Sadly, this hasn’t really worked.
I immediately loose some respect for the author. Just assuming there is an objective definition of good and evil is so... religious? It's all about context, assumptions, models held in minds, zeitgeist, etc. I find Rutger Bregman (Humankind) much more enlightened on this issue.
Imho grounding our moral compasses in science is working, as Rutger Bregman indicates.
Richard Wrangham seems to think there is a one dimensional scale of evil -> good, Nazis -> 'People helping Jews hide from Nazis'. If only it were that simple, if only it were impossible to split twins and have one end up a Nazi and one helping Jews. If only the good and evil never changed over time.