Interesting, however this is basically just a link article. If it was properly labeled and novel that would be ok. However, it is not labeled [link], and the psmag article has been linked to in discussion before.
They shared with their kin but rarely traded with outside groups. [...]
[In the Ultimatum game] the Machiguenga rarely refused even the lowest possible amount. “It just seemed ridiculous to the Machiguenga that you would reject an offer of free money,” says Henrich. “They just didn’t understand why anyone would sacrifice money to punish someone who had the good luck of getting to play the other role in the game.”
Um, so, people who rarely engage in trade, are not so keen to establish a reputation as someone who will not be taken advantage of. Even to my capitalist American ears, that seems just plain natural.
Not our typical cognitive biases, but does raise the question of universality - I am aware of much stronger evidence for the universality of emotions and facial expression. Skimming the paper looks like a lot of fun.
http://www.psmag.com/magazines/pacific-standard-cover-story/joe-henrich-weird-ultimatum-game-shaking-up-psychology-economics-53135
Actual paper:
http://www2.psych.ubc.ca/~henrich/pdfs/Weird_People_BBS_final02.pdf