The article doesn't mention that when this game is played with American children (using pieces of candy instead of money) they usually offer the least amount of candy and accept whatever's offered, say, a 9-1 split. This is seen as "rational" by both sides, because the giver should give as little as possible and the receiver should be happy to have something rather than nothing.
This behavior changes as people grow up. As teenagers, people generally won't accept a split worse than 70/30, which implies that it's worth it to lose out on the 30 in order to send a message to the stingy giver. Also, men are more likely to engage in this sort of justice-driven behavior than women, which is all considered economically irrational. But when the stakes get very high they tend to outweigh people's ethical notions of fairness.
This behavior changes as people grow up. As teenagers, people generally won't accept a split worse than 70/30, which implies that it's worth it to lose out on the 30 in order to send a message to the stingy giver. Also, men are more likely to engage in this sort of justice-driven behavior than women, which is all considered economically irrational. But when the stakes get very high they tend to outweigh people's ethical notions of fairness.