When we were rational

Stuart Armstrong at OvercomingBias has a good post on my new favorite topic:

In the real world, we could always hope that the march of science could replace superstitious explanations with truer ones. But the truth is already out there in these virtual worlds, and is ignored. If these games are the shape of things to come, it might well be that the zenith of rationality is already in the past.

Here's an exerpt from my recent paper "Overcoming Selfishness: Religion and the Alternatives":

Self-deception and belief go hand in hand. It is likely that self-deception evolved as a means to create and maintain belief, because as I have argued, belief works. In his 2002 Nobel lecture, Vernon Smith discusses some of his experiments involving the trust game. He finds that reciprocity is behind cooperation, not altruism or other-regarding utility. In other words, we achieve cooperation by deluding ourselves about our own altruism.
Immediately preceding the “invisible hand” statement, Adam Smith remarks on how wealth is created through the self-deception of the wealthy:

We are then charmed with the beauty of that accommodation which reigns in the palaces and oeconomy of the great; and admire how everything is adapted to promote their ease, to prevent their wants, to gratify their wishes, and to amuse and entertain their most frivolous desires. If we consider the real satisfaction which all these things are capable of affording, by itself and separated from the beauty of that arrangement which is fitted to promote it, it will always appear in the highest degree contemptible and trifling. But we rarely view it in this abstract and philosophical light. We naturally confound it in our imagination with the order, the regular and harmonious movement of the system, the machine or oeconomy by means of which it is produced. The pleasures of wealth and greatness, when considered in the complex view, strike the imagination as something grand and beautiful and noble, of which the attainment is well worth all the toil and anxiety which we are so apt to bestow upon it.
And it is well that nature imposes upon us in this manner. It is this deception which rouses and keeps in continual motion the industry of mankind. (TMS, IV.1.9-10)

But Adam Smith generally sees self-deception as an irrational and unsocial weakness that should be corrected:

He is a bold surgeon, they say, whose hand does not tremble when he performs an operation upon his own person; and he is often equally bold who does not hesitate to pull off the mysterious veil of self-delusion, which covers from his view the deformities of his own conduct. Rather than see our own behavior under so disagreeable an aspect, we too often, foolishly and weakly, endeavor to exasperate anew those unjust passions which had formerly misled us; we endeavor by artifice to awaken our old hatreds, and irritate afresh our almost forgotten resentments: we even exert ourselves for this miserable purpose, and thus persevere in injustice, merely because we once were unjust, and because we are ashamed and afraid to see that we were so. (TMS, III.4.4)

I think Smith, and most economists who have followed him, have failed to recognize the ecological value of individually irrational self-deception, i.e. its role in facilitating beliefs which benefit the group.
Robert Trivers (2006), the evolutionary sociobiologist, claims that self-deception evolved as a way to better deceive others. But he recognizes there must be a positive side as well, referring to what McCloskey (2006) and myself would call Hope: “Life is intrinsically future oriented and mental operations that keep a positive future orientation at the forefront result in better future outcomes (though perhaps not as good as those projected). The existence of the placebo effect is another example of this principle (though it requires the cooperation of another person ostensibly dispensing medicine). It would be very valuable to integrate our understanding of this kind of positive self-deception into the larger framework of self-deceptions we have been describing.”
Again, the positive side to self-deception is that it facilitates trust. Why else would it survive the selection process, and why would it continue to be so attractive? Despite the Enlightenment, we are drawn more than ever to myth-makers, inspirational speakers, emotional politicians, and thoughtless celebrities, not scientists and skeptics. Libertarians and economists know this from experience.

Addendum: Michael Prescott shows us the superstitions of a skeptic, Susan Blackmore. (Hat tip to commenter M.C.)