Confirmation Bias and Evolutionary Psychology

20 September 2011


William Blake (28 November 1757 – 12 August 1827)

If the Sun and Moon should doubt,
They’d immediately Go out.

William Blake, Auguries of Innocence

I was thinking about confirmation bias today and what a perfect topic of study this would be for evolutionary psychology. It is one thing to get at exactly what confirmation bias is in itself, and how it functions in distorting our thinking, but it is quite another matter to get to the root of confirmation bias and understand it in an Aristotelian sense, i.e., in terms of its causes.

As soon as I started to think about confirmation bias in the context of evolutionary psychology, it immediately made sense and revealed connections to other things that I’ve thought about.

What survival benefit could possibly derive from self-deception? At first thought this seems counter-intuitive. The persistence of discredited beliefs would seem to have a negative survival value. That is to say, stubbornly persisting in believing something to be true when it is not ought to land an agent in a good deal of trouble.

Coming at this from a different perspective, however, one can easily imagine the survival value of believing in oneself. There are many situations in which the difference between believing in oneself and not believing in oneself could mean the difference between survival and death. If this is true, then confirmation bias may lead to differential survival, and differential survival is the conditio sine qua non of differential reproduction.

In the Afterword to my Political Economy of Globalization I attempted to investigate what I called the “naturalistic basis of hope.” What does this mean? Hope has traditionally been treated as one of the three “theological virtues”: faith, hope, and charity. I wanted to investigate the phenomenon of hope from a naturalistic perspective; I would like to see hope understood in a non-theological sense, i.e., as a cardinal virtue rather than a theological virtue. (I made some remarks about hope in Very Short Treatise on Hope, Perfection, Utopia, and Progress, and continued in the naturalistic project with The Structure of Hope.)

I continue to believe that this naturalistic understanding of hope is an important undertaking, but when I wrote this Afterword about the naturalistic basis of hope, I didn’t make any connection between hope and evolutionary psychology. Hope comes in many forms, and one of these forms is a hope against all rational odds that things will go well for oneself. This kind of hope is a belief in oneself that would have survival value. (There are also forms of hope that are more explicitly supernaturalistic, and which nevertheless may also have survival value.)

This not only anthropocentric but also egocentric conception of hope has obvious limitations, but it stands in relation to other forms of hope that are less anthropocentric and less egocentric. In a more general sense than a belief in oneself that might give an advantage in survival, hope is an affirmation of one’s life not only in the present moment of struggle, but also throughout the course of one’s life — past, present, and future — and, in an even larger sense, one’s life taken on the whole, must be seen in the context of one’s life in the community taken on the whole. There is a sense, then, in which an egocentric hope is an affirmation of a wider community; this sense of hope may play a role in self-sacrifice, and the role of self-sacrifice in kin selection.

To live is to engage in an existential gamble. Pascal knew this, and this is why he framed his Christian (actually, Jansenist) apologetics in terms of a wager. The existential choices that we make that shape our lives (and shape the life of the community, to the extent that we are able to use our lives to shape the larger world) are bets that we place, and, when we act, we bet that the world is one way, and not another way.

If you place your bets unwisely, and invest your existential choices in dead ends, your life is wasted for all intents and purposes. To believe this to be the case — especially with a social species whose members need each other for cooperative survival — would be debilitating. To believe that one’s life was wasted because one believed the wrong thing would constitute a kind of spiritual suicide. I can’t imagine that many persons could keep this sense of wasted effort in mind and at the same time fully invest themselves in the business of furthering personal and communal survival.

To believe in one’s existential choices is probably a condition for optimal exertion in the struggle for life. In so far as confirmation bias makes it easier to believe in the rightness and righteousness of one’s existential choices, even in the face of conflicting evidence, it would have a substantial survival value, not only for the individual, but perhaps especially in regard to kin selection.

. . . . .

Fallacies and Cognitive Biases

An unnamed principle and an unnamed fallacy

The Truncation Principle

An Illustration of the Truncation Principle

The Gangster’s Fallacy

The Prescriptive Fallacy

The fallacy of state-like expectations

The Moral Horror Fallacy

The Finality Fallacy

Fallacies: Past, Present, Future

Confirmation Bias and Evolutionary Psychology

Metaphysical Fallacies

Metaphysical Biases

Pernicious Metaphysics

Metaphysical Fallacies Again

An Inquiry into Cognitive Bias by way of Memoir

The Appeal to Embargoed Evidence

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Grand Strategy Annex

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4 Responses to “Confirmation Bias and Evolutionary Psychology”

  1. Nick,

    A problem that I have with psychologists is their tendancy to describe common human behaviours as biases simply because they differ from their normative theory, without seeming to consider whether their normative theory is universally correct. I agree with you that we need to look at such things as strategies in the face of bounded rationality and – I suggest – uncertainty.

    Consider a game in which you have to get back to base by one of two routes, on either of which there may be an ambush. You start by assessing all available information and setting off on one route. The psychologists’ normative theory seems to suggest that as new information comes in you should re-assess which route is best. The actual game-theoretic solution is a bit more subtle. In psychological terms it might be like having a randomised degree of commitment to the route, and then discounting contrary evidence in proportion to your commitment. Wouldn’t this seem like confirmation bias or over-confidence? This theory would predict that people ought to have randomised degrees of biases, rather than a constant bias, which ought to be testable. Of course, it could be that slow old evolution has resulted in heuristics that are not currently appropriate, in which case we might strive to change them.


    • geopolicraticus said

      Dear Dave,

      Thanks for your remarkable comment. I have read it through carefully several times, and I can scarcely do justice to it.

      It is perhaps ironic that right after posting a longish piece in which I cited Wittgenstein’s criticism of psychology as conceptually confused that I should then next write a post about psychology. This wasn’t intentional, but I do think that evolutionary psychology offers the promise of cleaning up some of the confusions of traditional psychology.

      The parallel with biology is close. Think of the systematization of biology prior to Darwin, such as in Linnaeus. Biology then was little more than a catalog. Whether or not it could even be called a science is open to question, since it had not central, organizing scientific principle. Pre-Darwinian biology did have a central, organizing theological idea, but that would make it theology rather than science.

      Psychology also began in catalog fashion, but evolutionary psychology gives to psychology a systematic basis on which to build. The evolutionary dimension places things in time and in history, and that gives an over-arching scientific context in which they can be understood.

      That being said, I agree with you in so far as I understand you.

      Certainly the rational reevaluation of action in the light both of new evidence and past degree of confidence can be mistaken for confirmation bias. A subtle and fine-grained account of human behavior would have to incorporate this distinction.

      Certainly also evolution has given us heuristics that are not only inapplicable to life in industrial-technological civilization, but also, in some cases, these evolutionary strategies are disastrous.

      Much of the struggle to establish the legitimacy of scientific knowledge, which can be spectacularly counter-intuitive, is a struggle against our instincts. The fact that science has been as successful as it has been is a tribute to the human ability to disregard intuition and instinct in favor of rational self-interest. This bodes well for us.

      Human beings may seem random in their behavior, but even when they are being irrational, they are rarely truly random. (This fact is an aid to code-breakers everywhere. I once saw a documentary in which a cryptographer explained how the British often deciphered German communications encrypted by the Enigma machine because the operators of the machines were so predictable, i.e., non-random.) Thus any theory which attributes randomness to human behavior is suspect on its face.

      Best wishes,


  2. Nick,

    Another hypothesis would be this: that the normative theories of decision making (relative to which humans have a bias) implicitly presuppose a relative stability and certainty that was lacking in our evolutionary past – and may be lacking in our future. (think financial crisis.)



  3. […] can have  a whole conversation about the validity of evolutionary psychology and its tendency to confirmation bias. And as a person who quoted David Buss repeatedly in her disseration, I’m in no position to […]

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