We argue that because of a long history of intergroup conflict and competition, humans evolved to be tribal creatures. Tribalism is not inherently bad, but it can lead to ideological thinking and sacred values that distort cognitive processing of putatively objective information in ways that affirm and strengthen the views and well-being of one’s ingroup (and that increase one’s own standing within one’s ingroup). Because of this shared evolutionary history of intergroup conflict, liberals and conservatives likely share the same underlying tribal psychology, which creates the potential for ideologically distorted information processing. Over the past several decades, social scientists have sedulously documented various tribal and ideological psychological tendencies on the political right, and more recent work has documented similar tendencies on the political left. We contend that these tribal tendencies and propensities can lead to ideologically distorted information processing in any group. And this ideological epistemology can become especially problematic for the pursuit of the truth when groups are ideologically homogenous and hold sacred values that might be contradicted by empirical inquiry. Evidence suggests that these conditions might hold for modern social science; therefore, we conclude by exploring potential ideologically driven distortions in the social sciences.