The Republican Brain by is Mooney

of different views, so that their strengths and weaknesses could be debated—regarding, say, where it would be a good place to hunt today or whether the seasons are changing.
    Considered in this light, reasoning wouldn’t be expected to make us good logicians, but rather, good rhetoricians. And that’s what we are. Not only are we very good at selectively cobbling together evidence to support our own case—aided by motivated reasoning and the ubiquitous confirmation bias—but we’re also good at seeing the flaws in the arguments of others when they get up on top of the soap box, and slicing and dicing their claims (the so-called “disconfirmation bias”).
    When lots of individuals blow holes in one another’s claims and arguments, the reasoning of the group should be better than the reasoning of the individual. But at the same time, the individual—or the individual in a self-affirming group that does not provide adequate challenges—is capable of going very wrong, because of motivated reasoning and confirmation bias. Thanks to these flaws, the sole reasoner rarely sees what’s wrong with his or her logic. Rather, the sole reasoner becomes the equivalent of a crazy hermit in the wilderness—or, to quote the late Frank Zappa, the author of “that tacky little pamphlet in your Daddy’s bottom drawer.” And the unchallenged group member becomes like a cult follower.
    Mercier’s and Sperber’s “argumentative theory of reason” provides a strong case for supporting group reasoning processes like the scientific one, which are built around challenges to any one individual’s beliefs or convictions. These processes may be the only reliable check on our going vastly astray. By the same token, the theory also suggests that if you insulate yourself from belief challenge, you are leaving yourself vulnerable to the worst flaws of reasoning, without deriving any of the benefits of it.

    Humans may be relatively poor reasoners in comparison to some Enlightenment ideal. But that doesn’t mean every human is equally bad at reasoning. Nor does it mean that we’re all equally inflexible and unwilling to set aside our biases, or change our minds based on new evidence.
    At least as it is now constituted, the theory of motivated reasoning does not posit inherent liberal-conservative differences in biased reasoning tendencies. Yet I’ve already discussed a number of motivated reasoning studies—all relating to political or politicized beliefs—in which conservatives seemed to show more bias in favor of their preexisting views (or a stronger rejection of reality) than liberals did. And I also discussed an array of studies in which having more knowledge, or more political expertise, made conservatives’ biases worse, not better. All in all, I showed a lot of conservative wrongness, defensiveness, and overconfidence, in both public opinion studies and controlled psychology experiments.
    But how far can one go with this? It’s important to be cautious, because liberals have also been shown to engage in motivated reasoning—just not always as much as conservatives, or not in the same way. In fact, we’ll even encounter a few studies in later chapters in which liberals’ egalitarian values appeared to make them even more biased than conservatives, at least in key contexts.
    Other motivated reasoning studies, meanwhile, either don’t seem to examine the difference between liberals and conservatives closely, are not designed to do so, or in some cases, find the two groups to be equally biased. And the studies often use different parameters and designs, and focus on different political issues which may excite different emotions—which makes generalizing about them difficult.
    Moreover, it is important to reiterate that these motivated reasoning studies only capture individuals’ one-time reactions to inconvenient