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Posts Tagged ‘confirmation bias

interactional reasoning: cognitive or myside bias?

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In the previous post on this topic, I wrote of surprise as a motivator for questioning what we think we know about our world, a shaking of complacency. In fact we need to pay attention to the unexpected, because of its greater potential for harm (or benefit) than the expected. It follows that expecting the unexpected, or at least being on guard for it, is a reasonable approach. Something which disconfirms our expectations, can teach us a lot – it might be the ugly fact that undermines a beautiful theory. So, it’s in our interest to watch out for, and even seek out, information that undermines our current knowledge – though it might be pointed out that it’s rarely the person who puts forward a theory who discovers the inconvenient data that undermines it. The philosopher Karl Popper promoted ‘falsificationism’ as a way of testing and tightening our knowledge, and it’s interesting that the very title of his influential work Conjectures and refutations speaks to an interactive approach towards reasoning and evaluating ideas. 

In The enigma of reason, Mercier and Sperber argue that confirmation bias can best be explained by the fact that, while most of our initial thinking about a topic is of the heuristic, fast-and-frugal kind, we then spend a great deal more time, when asked about our reasoning re a particular decision, developing post-hoc justifications. Psychological research has borne this out. The authors suggest that this is more a defence of the self, and of our reputation. They suggest that it’s more of a myside bias than a confirmation bias. Here’s an interesting example of the effect:

Deanna Kuhn, a pioneering scholar of argumentation and cognition, asked participants to take a stand on various social issues – unemployment, school failure and recidivism. Once the participants had given their opinion, they were asked to justify it. Nearly all participants obliged, readily producing reasons to support their point of view. But when they were asked to produce counterarguments to their own view, only 14 percent were consistently able to do so, most drawing a blank instead.

Mercier & Sperber, The enigma of reason, pp213-4

The authors give a number of other examples of research confirming this tendency, including one in which the participants were divided into two groups, one with high political knowledge and another with limited knowledge. The low-knowledge group were able to provide twice as many arguments for their view of an issue as arguments against, but the high-knowledge performed even more poorly, being unable to provide any arguments against. ‘Greater political knowledge only amplified their confirmation bias’. Again, the reason for this appears to be reputational. The more justifications you can find for your views and decisions, the more your reputation is enhanced, at least in your own mind. There seems no obvious benefit in finding arguments against yourself.

All of this seems very negative, and even disturbing. And it’s a problem that’s been known about for centuries. The authors quote a great passage from Francis Bacon’s Novum Organum:

The human understanding when it has once adopted an opinion… draws all things else to support and agree with it. And though there be a greater number and weight of instances to be found on the other side, yet these it either neglects and despises, or else by some distinction sets aside and rejects, in order that by this great and pernicious predetermination the authority of its former conclusions may remain inviolate.

Yet it isn’t all bad, as we shall see in future posts…


Hugo Mercier and Dan Sperber, The enigma of reason, 2017

Written by stewart henderson

January 29, 2020 at 1:44 pm

interactional reasoning and confirmation bias – introductory

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I first learned about confirmation bias, and motivated reasoning, through my involvement with skeptical movements and through the Skeptics’ Guide to the Universe (SGU) podcast. As has been pointed out by the SGU and elsewhere, this confirmation bias, this strong tendency to acknowledge and support views, about any topic, that confirm our own, and to dismiss or avoid listening to views from the opposite side, is a feature of liberal and conservative thought in equal measure, as well as being as much a feature of highly credentialed public intellectuals’ thought as it is for the thinking of your average unlearned sot. The problem of confirmation bias, this ‘problem in our heads’, has been blamed for the current social media maladies we supposedly suffer from, creating increasingly partisan echo-chambers in which we allow ourselves, or are ‘driven by clicks’, to be shut off from opposing views and arguments.

But is confirmation bias quite the bogey it’s generally claimed to be? Is it possibly an evolved feature of our reasoning? This raises fundamental questions about the very nature of what we call reason, and how and why it evolved in the first place. Obviously I’m not going to be able to deal with this Big Issue in the space of the short blog pieces I’ve been writing recently, so it’ll be covered by a number of posts. And, just as obviously, my questioning of confirmation bias hasn’t sprung from my own somewhat limited genius – it pains me to admit – but from some current reading material.

The enigma of reason: a new theory of human understanding, by research psychologists Hugo Mercier and Dan Sperber, is a roolly important and timely piece of work, IMHO. So important that I launch into any attempt to summarise it with much trepidation. Anyway, their argument is that reasoning is largely an interactive tool, and evolved as such. They contrast the interactive view of reason with the ‘intellectualist’ view, which begins with Aristotle and his monumentally influential work on logic and logical fallacies. So with that in mind, they tackle the issue of confirmation bias in chapter 11 of their book, entitled ‘Why is reason biased?’

The authors begin the chapter with a cautionary tale, of sorts. Linus Pauling, winner of two Nobel Prizes and regarded by his peers as perhaps the most brilliant biochemist of the 20th century, became notoriously obsessed with the healing powers of vitamin C, in spite of mounting evidence to the contrary, raising the question as to how such a brilliant mind could get it so wrong. And perhaps a more important question – if such a mind could be capable of such bias, what hope is there for the rest of us?

So the authors look more closely at why bias occurs. Often it’s a matter of ‘cutting costs’, that is, the processing costs of cognition. An example is the use of the ‘availability heuristic’, which Daniel Kahneman writes about in Thinking fast and slow, where he also describes it as WYSIWTI (what you see is what there is). If, because you work in a hospital, you see many victims of road accidents, you’re liable to over-estimate the number of road accidents that occur in general. Or, because most of your friends hold x political views, you’ll be biased towards thinking that more people hold x political views than is actually the case. It’s a kind of fast and lazy form of inferential thinking, though not always entirely unreliable. Heuristics in general are described as ‘fast and frugal’ ways of thinking, which save a lot in cognitive cost while losing a little in reliability. In fact, as research has shown (apparently) sometimes heuristics can be more reliable than pains-taking, time-consuming analysis of a problem.

One piece of research illustrative of fast-and-frugal cognitive mechanisms involves bumble-bees and their strategies to avoid predators (I won’t give the details here). Why not? Reasoning as an evolved mechanism is surely directed first and foremost at our individual survival. To be more preservative than right. It follows that some such mechanism, whether we call it reasoning or not, exists in more or less complex form in more or less complex organisms. It also follows from this reasoning-for-survival outlook, that we pay far more attention to something surprising that crops up in our environment than routine stuff. As the authors point out:

Even one-year-old babies expect others to share their surprise. When they see something surprising, they point toward it to share their surprise with nearby adults. And they keep pointing until they obtain the proper reaction or are discouraged by the adults’ lack of reactivity.

Mercier & Sperber, The enigma of reason, p210

Needless to say, the adults’ reactions in such an everyday situation are crucial for the child – she learns that what surprised her is perhaps not so surprising, or is pleasantly surprising, or is dangerous, etc. All of this helps us in fast-and-frugal thinking from the very start.

Surprises – events and information that violates our expectations – are always worth paying attention to, in everyday life, for our survival, but also in our pursuit of accurate knowledge of the world, aka science. More about that, and confirmation bias, in the next post.


The enigma of reason: a new theory of human understanding, by Hugo Mercier & Dan Sperber, 2017

Written by stewart henderson

January 28, 2020 at 2:13 pm