Let’s Not Kid Ourselves – We Are All Irrational

March 17, 2010 at 6:44 pm (Miscellaneous) (, , , , , )

Are human beings rational? No. In fact, Stuart Sutherland managed to write an entire book on the Irrationality of people.

Here is a review of Stuart Sutherland’s Irrationality. I think this quote is worth reproducing here:

“First published in 1992, Irrationality proposes, and to any reasonable mind proves, that we are for the most part credulous fools who would do well, in most circumstances, to stop and think before we go and do something stupid; for stupid things are what we often end up doing, however much we congratulate ourselves on being rational animals. The book’s conclusions would appear to be just as valid in 2007 as they were 15 years ago.”[My italics.]

In his introduction, Sutherland writes that his purpose is to “demonstrate that people are very much less rational than is commonly thought and to set out systematically why this is so”. Sutherland points out that no-one (including himself) is exempt. I would suggest that anybody who doubts that people are irrational creatures reads this book.

There are chapters in the book headed Ignoring the Evidence, Distorting the Evidence, Misinterpreting the Evidence, and Mistaken Connections in Medicine. Here are some “morals” suggested at the end of these chapters:

  • Search for evidence against your own beliefs.
  • Don’t distort new evidence: consider carefully whether it could be interpreted as disconfirming your beliefs rather than supporting them.
  • Be wary of your memory: you are likely to recall whatever fits with your current views.
  • Beware of being influenced by any explanations you may have concocted in support of your own beliefs.
  • […] Don’t trust small samples.
  • Beware of biased samples.

These are seemingly simple rules, but they are rules that I sometimes find hard to follow.

The problem, as I see it, is that in order to avoid holding irrational views, one must first recognise that one is being (or has been) irrational in forming these views.

Identifying yourself as a skeptic is no guarantee of rationality. In fact, I wonder if it might in some cases lead to complacency. Perhaps if you see yourself as a skeptic and a critical thinker, you will be more likely than others to see your views as ‘rational’ – and therefore fail to see the irrationality of some of your views?

I suspect that different people will find some of the ‘rules’ I listed above easier to follow than others. They might, say, find it easy to cultivate a healthy skepticism toward small samples – yet trust their memory more than they should.

There is a list of memory biases on Wikipedia which nicely illustrates why we should be wary of the extent to which we trust our memory. You should perhaps put no more faith in your memory than you would in the conclusions drawn from a small (or biased) sample.

The first two ‘rules’ on Sutherland’s list (searching for evidence against your beliefs and avoiding distorting new evidence) are probably rules I break constantly. Perhaps not when reading up on the placebo effect, but certainly in other circumstances.

Here’s where this skeptic has most recently caught himself out: I watch my local football team and found myself complaining bitterly about other teams “bullying” us on the field by committing clear fouls which are ignored by the referee.

Being interested in irrationality, and having previously commented elsewhere on the irrationality of football fans, I wondered for a moment whether my views were coloured by failing to seek out contradictory evidence due to a bias toward the home team.

I set out to consciously look out for examples of home and opposition centre halves fouling opposing players and was a little surprised to find that, actually, the home players committed roughly as many unpunished fouls as the opposition players.

That’s the thing about irrationality – you have to be aware of it in order to guard against it. You have to, for example, force yourself to look for contradictory evidence, and you must ensure that you do not distort it if and when you find it.

My irrationality in this case may have been more “available” to me than it would be in other areas. My being interested in irrationality and aware of the irrationality of sports fans may have made it easier for me to spot my irrational view of events on the field.

What can we do to avoid falling into irrationality so often? I would guess that being more aware of the likelihood of doing so may help. Perhaps we should all read Sutherland’s Irrationality once a year simply to remind ourselves of what irrational creatures we really are?



  1. Uponnothing said,

    Just finished reading this book myself. Every reader of any newspaper should read it.

  2. Michael said,

    Adding some more irrationality into the mix, that is how I interpret the lines “Forgive us our trespasses, as we forgive those who trespass against us” from the Lord’s Prayer in the context of modern knowledge.

    Sutherland’s book duly added to my wish list.

  3. James Cranch said,

    I think the most important thing is to filter things on the way out of our brains, as well as on the way in.

    It’s good to get into the habit, when we make a decision or say something, of asking ourselves how we’d justify it if we had to (and occasionally actually doing so just to check). I think that’s much more helpful than deciding which things to believe when we hear them, then coming to think what what we believe is infallible.

  4. softestpawn said,

    I think many of us could write dozens of rambling books about the irrationality of people, especially those who label themselves as rational (atheists, skeptics…) and so think themselves immune.

    Of course, now that we’ve shown how much we recognise people’s irrationality, we are more aware of it, able to look out for it, and are therefore more rational than anyone else, and by doing so are mostly immune to being irr….


  5. It’s not the PR, It’s the Practice, Stupid « SoftestPawn’s Weblog said,

    […] It includes people who are quite capable of thinking critically. Commercial statisticians, professional software engineers, private practice psychologists and police detectives all have to apply such practices to their work, whether or not we do in general. […]

  6. Woo In Sport « Stuff And Nonsense said,

    […] an offence on the football field, Arsene Wenger “didn’t see it”. But then, we are all irrational. One might be tempted to offer a few words of advice for Arsene to consider next time one of his […]

  7. Beware The Bias Blind Spot « Stuff And Nonsense said,

    […] written previously that we are all irrational, and asserted that you have to be aware of your irrationality in order to guard against it. It […]

  8. The Year In Nonsense. And Stuff. « Stuff And Nonsense said,

    […] March, I wrote about one of my favourite books, Irrationality by Stuart Sutherland: Let’s not kid ourselves – we are all irrational. I also mentioned again one of my unsung heroes of science – Janet Lane-Claypon (this time […]

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