How irrational are we?

Some people think that the human condition is essentially one of “irrationality” – that we are all cognitively flawed in a deep and irredeemable sort of way.

I don’t think we’re quite as bad as that. I have three sorts of reasons for thinking we’re not as irrational as pessimists think. But alas, I also have two sorts of reasons for thinking we’re still far from perfect.

My first sort of reason to think we’re not all that irrational stems from agreement with Hume that reason is “the slave of the passions, and can never pretend to any other office than to serve and obey them”. This means that “the heart wants what the heart wants”, and “the head” works out how best to achieve it. And only “the head” is capable of being rational or irrational. For example, smokers are often treated as if they were making a mistake. But according to Hume’s way of thinking, they have simply made an alternative lifestyle choice. They value their health less highly than non-smokers, of course, but that can’t be regarded as a case of irrationality. They’re doing what they want to do, and wants aren’t capable of being irrational.

By dividing the activities of the mind into volition and cognition, this approach effectively insulates the first “half” of them from rational criticism. Rationality doesn’t apply to the having of desires as it does apply to the formation of beliefs.

My second sort of reason to think we aren’t all that irrational draws on the ideas of recent philosophers like Dennett and Davidson. According to their variety of pragmatism, the content of a belief is a matter of interpretation. That is, a belief is about whatever a fully-informed interpreter would say it is about. To see how this works, consider an ultra-simple rudimentary agent such as a thermostat. Suppose it keeps the room at a steady 70 degrees. Then, as interpreters, we would say its (rudimentary) goal or “desire” is to keep the room at 70 degrees, and that its (rudimentary) “belief” is that the room is either hot enough or else not hot enough, depending on whether or not its bimetal strip is distorted enough to break the circuit to the heater. Even if the bimetal strip is permanently bent with age, and the dial “says” the thermostat should be keeping the room at 80 rather than 70 degrees, what counts is not what the dial “says” but what it actually does.

This is relevant, because much human irrationality is supposed to emerge when belief and action have become “decoupled”. For example, suppose someone looks up at the sky and says, “oh dear – I think it’s going to snow!” But then he puts on Wellington boots and a raincoat, grabs an umbrella, and so on. On the face of it, that seems like irrational behaviour. But let’s look more closely. If his behaviour is consistent with someone who thinks it is going to rain rather than snow, interpretation leads us to assign the belief that it is going to rain rather the belief that it is going to snow. We simply override his own report of what he thinks. He is probably using the word ‘snow’ in an aberrant way, much as the thermostat’s dial “said” – inaccurately – that its goal was to keep the room at 80 degrees. That is a linguistic misunderstanding rather than a case of irrational action or irrational belief. We are obliged to re-interpret the contents of the agent’s mind so as to maximize the rationality of his actions and beliefs, and when we do so, we find far less “decoupling” than we originally feared.

My third sort of reason to think we aren’t all that irrational comes from evolutionary theory. Like other creatures, we evolved to survive at least to the point where we have successfully reared offspring. This entails that as far as everyday beliefs that guide behaviour are concerned, most are probably true or approximately true. It also entails that they can’t contradict each other very much. Imagining a creature with a lot of false or contradictory beliefs is like imagining a creature that walks into closed doors, doesn’t avoid cliff edges, and so on. And that is to imagine a creature that can’t survive long enough to reproduce, like a soluble fish, as Dennett remarked.

So much for three sorts of reason for thinking we’re not as irrational as we might fear. All of them are consistent we the idea that we are “survival machines” for our genes. For that, we have to be reasonably efficient vehicles for their passage into future generations, and for that, we have to do our cognitive work reasonably well. I see the pessimistic alternative as being inspired by more traditional “takes” on the human condition. The idea that we are cursed from birth with the madness of irrationality is reminiscent of the doctrine of Original Sin. The idea that our minds are not subject to fine-tuning through constant interaction with the physical world is reminiscent of mind-body dualism. The idea that cognitively speaking we are in a place of “darkness” is reminiscent of radical Cartesian scepticism.

We can avoid those sources of pessimism by moving beyond our religious traditions. But the alternative evolutionary perspective brings its own brands of pessimism with it. I can see two sorts of reason for thinking we aren’t quite as rational as we might hope.

The first stems from the fact that we are a social animal. Much of our thought is guided by moral concerns, and by empathy for members of our own group (which is often not at all “moral” in any obvious sense, as it discriminates against members of other groups).

There is strong selective pressure against the sort of false beliefs that would lead us to walk into closed doors or over the edge of cliffs. But the selective pressure against false beliefs of a more “theoretical” sort – such as beliefs in religion, history, or even science – is much weaker. In fact any selective pressure here is probably negative – that is, the social advantage of having similar beliefs to others outweighs any disadvantage attached to their being false. The positive effects on our gene-propagating potential of having the same beliefs as others spring from the way they help to identify which group we belong to, which hymn sheet we’re singing from, and where our allegiances lie. And above all whom we can turn to for help if we need it. Truth here takes a second place to reciprocal altruism.

If we want to have true beliefs of this theoretical sort, and practically everyone who professes to have a “scientific” outlook does, then we are going to have to control our urge to “belong”. Such urges militate against truth, and given a truth-oriented outlook they are irrational.

I don’t see much effort made to control these “social” urges. Most current academic philosophers’ energies seem to be expended more on saying popular, agreeable things and avoiding any real controversy. Wider attitudes to “denialists” of one sort or another seem not to have advanced one inch beyond the opprobrium traditionally heaped on heretics, infidels, apostates and blasphemers. Just adopting a new word for non-co-religionists does not auger well for our pursuit of truth or for human rationality.

The second sort of reason to think we aren’t as rational as we’d hope has to do with sexual selection. In sexual selection, members of the selected sex exhibit dangerous or expensive ornaments and engage in self-destructive or wasteful behaviour in order to send a “costly signal”. A signal has to be costly to be convincing – hence the length, inconvenience and danger of owning a peacock’s tail.

In humans, as in monogamous birds, each sex is subject to selection by the other sex. Both men and women bear the marks of this process of selection. For example, permanent and cumbersome human breasts signal fertility and youth. Tribalism and earning power signal strength and intelligence. But being well-endowed or getting paid a lot of money doesn’t make anyone more truthful or more competent in their pursuit of truth.

The combination of sociality and sexual selection in humans has given rise to some bizarre social arrangements, including – in some parts of the world and much of history – the segregation of the sexes. In these arrangements women are in effect incarcerated, and men in effect spend their days slapping each other’s asses with wet towels in changing rooms.

None of that is conducive to truth or to human freedom. If we primarily value truth or freedom, promoting the opposite may be a typically wasteful self-handicapping “signal” – but it’s irrational.

So much for human irrationality as I see it. Shall we say: three out of five ain’t bad?

4 thoughts on “How irrational are we?

  1. I’ll have to blog a reply because I agree in some aspects and disagree in others.

    I address one bugbear here though: the sexual selection theory of breasts. It really doesn’t work. Breasts are most impressive while pregnant or lactating – not the best times to mate. On the other hand there are excellent mechanical reasons for breasts when attempting to feed a flat-faced, largely immobile and heavy infant which a chimpanzee does not face with her protruding faced, relatively lighter infant who can cling to her body. The cynic in me suspects that’s a less…sexy hypothesis though.

    • Personally, I think the reasons “for” are more numerous and more compelling than any “against”. The former include:

      (1) Humans are the only animal that has permanent breasts – i.e. breasts that are present even when not lactating. That is a remarkable fact that calls for explanation.

      (2) Fat is an obvious signal of “health and wealth” – especially where food is scarce, as it would have been during most of our evolutionary development. In humans, male sexual interest is drawn by the presence of fat – and therefore fertility – in other parts of the female body such as buttocks, round cheeks, etc.

      (3) Large breasts are a definite “encumbrance”, even for non-athletic activities. This suggests a costly signal that conforms to Zahavi’s handicap principle. They are also dangerous from a health point of view.

      (4) There is much variation in breasts – another classic mark of sexual ornamentation.

      (5) Breasts arouse erotic interest in both men (as object of “gaze”, etc.) and women (as “erogenous zone”).

      I suspect there are political reasons why some people would prefer it if we didn’t think about breasts “that way”. For example, some feminists don’t like the idea that men exercise any sort of sexual selection at all – and promote an image of a “natural” human society as being more like that of deer, with males ignorantly banging their thick skulls against each other impulsively. Meanwhile, nurturing “Bambi’s mother” types use their kindness, intelligence and judgement for the betterment of all!

      For their part, some men quite like that idea of human society too. They fancy themselves to be “the chosen ones” – whose natural role doesn’t involve engaged parenthood. (Surprise?!)

      I hope it’s pretty obvious that humans are essentially a monogamous ape, like gibbons. Human offspring like gibbon offspring normally require the engagement of both parents. This requirement would have been critical during most of our evolutionary past, when food was harder to come by.

      It’s understandable that breast-feeding mothers would prefer not to attract the attention of sexually-interested men. So some are inclined to “pretend” to themselves that breasts have “nothing to do with sex at all” and a fortiori cannot function as ornaments of sexual selection. It’s also understandable that some gay men (who find breasts uninteresting sexually) would find it more of a stretch of the imagination to see breasts as an ornament. But these aren’t good reasons for rejecting the theory that they are.

      Some puritanically-minded people are uncomfortable with the idea that a single body part could serve more than a single evolutionary purpose, especially if one of those purposes is sexual and the other involves young children. To which I can only reply: that’s life, I’m afraid!

      • Rather amused by that 🙂 No, not a puritanical or squeamish reaction at all. It’s clear that breasts ARE an object of interest to men – why deny it? But I’d also note it’s culturally specific. Societies in which women do not conceal their breasts tend to have men rather less interested in breasts as sexual items (perhaps viewed more like cheeks, your other example).

        If the breast is intended to move the nipple away from the ribcage, then what other way would it be done? Lactating chimps show hardly any change in breast size. Surely storing fat over a long period, and before requiring additional energy to build or feed progeny is a more parsimonious solution?

        Regarding encumbrance – really, it’s not that bad. If women can sustain a hunter-gatherer lifestyle with breasts, I think its unlikely to be a severe handicap. Certainly less so than a peacock tail.

        As for variation, since this is true of a number of human features (hair being the most obvious) I’m not convinced that alone provides a clear case in support.

        It’s not an especially /masculine/ theory in my opinion, just one very bound up in Western culture which has its own hang ups 🙂

        • I don’t think interest in this or that part of the human body is culturally specific. I think that’s a good example of how social cohesion leads us away from truth.

          There are social situations in which “playing it cool” is de rigueur, whether this involves disguising sexual interest or temporarily “turning it off”. For example, consider the legendary Teutonic capacity for “being comfortable with nudity”, or our own ability to suspend ogling for a few hours while on a beach. In both cases, far more flesh is visible than in everyday work situations, say, and – superficially at least – people appear to be “not interested”. But that interest returns, to the same parts of the body, in more “appropriate” situations of greater intimacy. There may be a lower birth rate in Teutonic countries than elsewhere, but there’s no evidence that they’re “less interested in sex” than we are. Nor is there any evidence that they’re uninterested in the parts of the human body that interest us.

          There are big differences between cultures in how revealing clothing can be, but few differences in the social situations in which people are expected to be “cool”. For example, it’s much easier for men and women to “judge” buttocks in Western dress than in much Middle Eastern dress. But the amount of semi-disguised, not-fully-acceptable public ogling seems to be about the same. I’m sure the amount of sexual interest (on the part of both sexes) in buttocks is about the same as well. We all belong to the same species after all. So I’d argue there is little difference between human cultures as to which parts of the human body are “areas of outstanding interest” or “erogenous zones”.

          Regarding encumbrance – really, it’s not that bad. If women can sustain a hunter-gatherer lifestyle with breasts, I think its unlikely to be a severe handicap. Certainly less so than a peacock tail.

          It doesn’t have to be a “severe” handicap, but the theory says it should “cost” enough for its “message” to be convincing. For that, it has to cost something, in other words it should be a burden of some sort, even if in most cases a light one.

          Humans are closely related to (and no doubt descended from) other apes whose mammary glands return to a roughly “male” order of magnitude when not lactating. We are different because a deviation/ development occurred, and these things occur for a “reason”, driven by an evolutionary “purpose”.

          As for variation, since this is true of a number of human features (hair being the most obvious) I’m not convinced that alone provides a clear case in support.

          I’m glad you mentioned hair, because I think hair is another human ornament of sexual selection – for both sexes. Most hair on apes just grows, reaches maturity, then falls out at a regular “turnover” rate. Ours does too – everywhere except on the head. Head hair (or the lack of it – on the chin in women, on the pate in older men) strikes me as another area of human sexual interest. Some societies demand that women’s hair be covered (like breasts). It’s an area where fastidiousness and use of tools such as combs and sharp blades can be judged. It’s often an encumbrance or a liability (lice). Even the lack of it is a liability (think of bald men under the burning sun.) Women would prefer to avoid “male pattern baldness”, just as men would prefer to avoid “moobs”. And so on. This all bespeaks sexual selection to me.

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