To the child, Nature gives various means of rectifying any mistakes he may commit respecting the salutary or hurtful qualities of the objects which surround him. On every occasion, his judgments are corrected by experience ... In the study and practice of the sciences it is quite different; the false judgments we form neither affect our existence nor our welfare; and we are not forced by any physical necessity to correct them. Imagination, on the contrary, which is ever wandering beyond the bounds of truth, joined to self-love and that self-confidence we are so apt to indulge, prompt us to draw conclusions that are not immediately derived from facts ... Antoine Lavoisier (1743-1794)
Clothes are both "functional" and "social". Functionally, clothes keep us warm and cool and dry, protect us from injury, maintain privacy, and help us carry things. But since they are usually visible to others, clothes also allow us to identify with various groups, to demonstrate our independence and creativity, and to signal our wealth, profession, and social status. The milder the environment, the more we expect the social role of clothes to dominate their functional role. (Of course social roles are also "functions" in a sense; by "functional" I mean serving individual/personal functions.)
Beliefs are also both functional and social. Functionally, beliefs inform us when we choose our actions, given our preferences. But many of our beliefs are also social, in that others see and react to our beliefs. So beliefs can also allow us to identify with groups, to demonstrate our independence and creativity, and to signal our wealth, profession, and social status.
For example, a belief that the local sports team will do well can help me associate with my locality. A belief that my future looks bright can help me attract a mate. A belief that UFOs are aliens could help me signal that I'm an independent thinker, while a belief that UFOs are bunk could help me signal my scientific education. A belief that a Democrat would make a better president could help me signal my caring and concern about others.
For subjects where there is little social monitoring and strong personal penalties for incorrect beliefs, we expect the functional role of beliefs to dominate. Beliefs about military missions or engineering projects come to mind. But for subjects with high social interest and little personal penalty for mistakes, we expect the social role of beliefs to dominate. Consider beliefs about large elections or beliefs addressing abstract philosophical, religious, or scientific questions.
If people could wear a parka undetected underneath a bikini, bikinis might be in fashion in the Arctic, and Arctic folks wouldn't need to trade off the functional and social roles of clothes. Similarly, if people could choose their external behavior independently of their internal beliefs, then internal beliefs would never need to be anything but a person's best computationally-feasible estimate of the way things really are. But since it is typically hard to say one think and believe another, the functional and social roles of beliefs do conflict.
Assuming this story is valid, what do we do? I think it is a mistake to assume that the solution is to educate people about how to better construct more individually-functional beliefs. It is not obvious that, given typical preferences over functional vs. social outcomes, people are biased toward the social role of beliefs. Of course more education on either role can help people get better results without hurting the other role. But more education costs more, and it is not obvious that people are biased against such educational spending.
The conflict between the functional and social roles of clothes seems less of a concern with the invention of new materials and designs, and as we have become rich enough to move to milder climates. Similarly, the conflict between the personal and social roles of beliefs may be reduced as we invent new belief complexes, and as we come to better understand both roles, especially the academically-neglected social role of beliefs.
Just as it seems that teenage smoking can't be reduced much without giving teenagers good substitute ways to show their independence and worldliness, the social costs of mistaken beliefs about politics and UFOs probably can't be reduced much without giving people good substitute ways to show their concern and independence. But it is hard to create substitutes for things before you understand in some detail the functions they now perform.
Also, the conflict between the individual and social role of beliefs can be muted by the invention of better social institutions, such as political parties or academic journals, to which people can delegate their actions. Within such institutions, social relations may be structured so that social pressures are better aligned with individual pressures on beliefs, at least regarding the delegated actions. But, again, it is hard to design better institutions with only a fuzzy understanding of these pressures.
Fortunately, innovation in clothes long proceeded without a deep understanding of either fabrics or the social and functional roles of clothes. Similarly, belief complexes and social institutions have evolved even without a deep understanding of the nature of belief and computation and of the social and functional roles of beliefs. But there is reason to hope that, as with clothes, such evolution may proceed faster with a deeper understanding of these issues.