If you look at humanity, both today and throughout history, you can’t help but notice that people believe a lot of things that seem stupid and irrational. Pick your favourite example: conspiracy theories, religion, prejudice, ideology, pseudoscience, ancestor myths, people who hold different political opinions from your own, and so on.

This observation provokes a central question for the social sciences. Why do broadly rational people, people who often seem intelligent and competent in most aspects of their lives, sometimes believe highly irrational things?

One classic answer is that people are not disinterested truth seekers. In some contexts, our practical interests conflict with the aim of acquiring accurate, evidence-based beliefs. For example, we might want to believe things that make us feel good, that impose a satisfying order and certainty on a complex world, that help us persuade others that we’re noble and impressive, or that win us status and approval from our friends and allies.

Famously, when our goals come into conflict with the pursuit of truth in this way, the truth often loses out. We lie to ourselves, bury our heads in the sand, and engage in elaborate mental gymnastics. Less colloquially, we engage in what psychologists call “motivated cognition”: we—or our minds, at least—direct cognitive processes toward favoured conclusions, not true ones. For example, we instinctively seek out evidence that confirms those conclusions (confirmation bias), shield ourselves from evidence against them (motivated ignorance), insist on higher standards for arguments we dislike than for those we like (biased evaluation), and remember and forget information in convenient patterns (selective forgetting).

Throughout most of history, scholars had little doubt that this tendency was a central and destructive feature of the human condition.

For Adam Smith, for example, it “is the fatal weakness of mankind” and “the source of half the disorders of human life.” For Socrates in the Cratylus, “the worst of all deceptions is self-deception.” And of course, thinkers such as Freud and Nietzsche placed motivated cognition at the centre of their understanding of human psychology.

Against Motivated Cognition

This consensus continued from the emergence of scientific psychology until relatively recently. In the last decade or so, however, some researchers have become increasingly sceptical that motivated cognition is a significant force in human affairs. There are many reasons for this, including reinterpretations