All reasoning is in service of winning arguments? I knew it all along! It's hard for me to express any skepticism of the study cited in this New York Times article without going all meta, so I'll just let the article speak for itself:
Now some researchers are suggesting that reason evolved for a completely different purpose: to win arguments. Rationality. . . is nothing more or less than a servant of the hard-wired compulsion to triumph in the debating arena. According to this view, bias, lack of logic and other supposed flaws that pollute the stream of reason are instead social adaptations that enable one group to persuade (and defeat) another. Certitude works, however sharply it may depart from the truth.
The idea, labeled the argumentative theory of reasoning, is the brainchild of French cognitive social scientists, and it has stirred excited discussion (and appalled dissent) among philosophers, political scientists, educators and psychologists, some of whom say it offers profound insight into the way people think and behave.
The Times ran a follow up blog post from one of the researchers cited in the piece, Hugo Mercier, who defends his thesis here:
We do not claim that reasoning has nothing to do with the truth. We claim that reasoning did not evolve to allow the lone reasoner to find the truth. We think it evolved to argue. But arguing is not only about trying to convince other people; it’s also about listening to their arguments. So reasoning is two-sided. On the one hand, it is used to produce arguments. Here its goal is to convince people. Accordingly, it displays a strong confirmation bias — what people see as the “rhetoric” side of reasoning. On the other hand, reasoning is also used to evaluate arguments. Here its goal is to tease out good arguments from bad ones so as to accept warranted conclusions and, if things go well, get better beliefs and make better decisions in the end.
If you'd rather, you can click here to read the study itself, or see a summary located at Hugo Mercier's own website, or listen to Edge.org's interview with him. Viewing the video below is optional; in fact, you probably shouldn't.