All men are created equal
But some men are more equal then the others
OK, I admit. That was a twist of George Orwell's Animal Farm (which was itself a twist of the Declaration of Independence).
What I want to say is this study argued that some men - those with higher level of testosterone - prefers to be equally poor than being a bit richer while the other men become a lot richer. (If you don't want to see the whole paper, see the Economists' review.)
The researcher run an experiment using a series of ultimatum game, played by some Harvard students who have taken microeconomics. After the experiment, he took saliva samples from the students and compare their testosterone levels. The result: responders who rejected a low final offer had an average testosterone level more than 50% higher than the average of those who accepted.
The implication of this study, is as The Economist wrote:
... what people really strive for is relative rather than absolute prosperity. They would rather accept less themselves than see a rival get ahead. That is likely to be particularly true in individuals with high testosterone levels, since that hormone is correlated with social dominance in many species.
In other words, the more masculine someone is, the less important is money. It's how your position compared to the other.
However, i was informed by Tirta about a very important caveat. Read also the first comment to the post.
Nevertheless, this study was a valuable additional literature to a debate on inequality I encountered somewhere (read my summary here and here, and a relevant discussion here).