I highly doubt our common ancestors lived in social Altruism. It is easy to look at the past through rose coloured glasses to pick and choose what we like.
Tribes are an interesting choice of example. Internally very supportive, externally very opportunistic. There is a very clear division of Us and Them and very clear rules for dealing with the two.
"Our evolved brains empower us to rebel against our selfish genes"-Richard Dawkins
Hmm... but what do we do with that empowerment. How many people even think about this stuff?
Back to you Huxley.
