an autodidact meets a dilettante…

‘Rise above yourself and grasp the world’ Archimedes – attribution

Posts Tagged ‘reason

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…

Reference

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

Written by stewart henderson

January 29, 2020 at 1:44 pm

preliminary thoughts on reasoning and reputation

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In my youth I learned about syllogisms and modus ponens and modus tollens and the invalidity of arguments ad hominem and reductio ad absurdum, and valid but unsound arguments and deduction and induction and all the rest, and even wrote pages filled with ps and qs to get myself clear about it all, and then forgot about it. All that stuff was only rarely applied to everyday life, where, it seemed, our reasoning, though important, was more implicit and intuitive. What I did notice though – being a bit of a loner – was that when I did have a disagreement with someone which left a bitter taste in my mouth, I would afterwards go over the argument in my head to make it stronger, more comprehensive, more convincing and bullet-proof (and of course I would rarely get the chance to present this new and improved version). But interestingly, as part of this process, I would generally make my opponent’s argument stronger as well, even to the point of conceding some ground to her and coming to a reconciliation, out of which both of us would be reputationally enhanced.

In fact, I have to say I spend quite a bit of time having these imaginary to-and-fros, not only with ‘real people’, but often with TV pundits or politicians who’ll never know of my existence. To take another example, when many years ago I was accused of a heinous crime by a young lad to whom I was a foster-carer, I spent excessive amounts of time arguing my defence against imaginary prosecutors of fiendish trickiness, but the case was actually thrown out without my ever having, or being allowed, to say a word in a court-house, other than ‘not guilty’.

So, is all this just so much wasted energy? Well, of course not. For example, I’ve used all that reflection on the court case to give, from my perspective, a comprehensive account of what happened and why, of my view of the foster-care system and its deficiencies, of the failings of the police in the matter and so forth, to friends and interested parties, as well as in writing on my blog. And it’s the same with all the other conversations with myself – they’ve sharpened my view of the matter in hand, of people’s motivations for holding different views (or my view of their motivations), they’ve caused me to engage in research which has tightened or modified my position, and sometimes to change it altogether.

All of this is preliminary to my response to reading The enigma of reason, by Dan Sperber and Hugo Mercier, which I’m around halfway through. One of the factors they emphasise is this reputational aspect of reason. My work to justify myself in the face of a false allegation was all about restoring or shoring up my reputation, which involved not just explaining why I could not have done what I was accused of doing, but explaining why person x would accuse me of doing it, knowing I would have to contend with ‘where there’s smoke there’s fire’ views that could be put, even if nobody actually put them.

So because we’re concerned, as highly socialised creatures, with our reputations, we engage in a lot of post-hoc reasoning, which is not quite to say post-hoc rationalisation, which we tend to think of as making excuses after the fact (something we do a lot of as well). A major point that Sperber and Mercier are keen to emphasise is that we largely negotiate our way through life via pretty reliable unconscious inferences and intuitions, built up over years of experience, which we only give thought to when they’re challenged or when they fail us in some way. But of course there’s much more to their ‘new theory of human understanding’ than this. In any case much of what the book has to say makes very good sense to me, and I’ll explore this further in future posts.

Written by stewart henderson

January 20, 2020 at 2:05 pm

What is inference?

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Don’t believe everything you read

What are you inferring?

So am I to infer from this you’re not interested?

What does inferring actually mean? What is it to ‘infer’? Does it require language? Can the birds and the bees do it? We traditionally associate inference with philosophy, which talks of deductive inference. For example, here’s a quote from Blackwell’s dictionary of cognitive science:

Inferences are made when a person (or machine) goes beyond available evidence to form a conclusion. With a deductive inference, this conclusion always follows the stated premises. In other words, if the premises are true, then the conclusion is valid. Studies of human efficiency in deductive inference involves conditional reasoning problems which follow the “if A, then B” format.

So according to this definition, only people, and machines constructed by people, can do it, deductively or otherwise. However, psychologists have pretty thoroughly demolished this view in recent years. In ‘Understanding Inference’, section 2 of their book The enigma of reason, cognitive psychologists Hugo Mercier and Dan Sperber explore our developing view of the concept.

Inference is largely based on experience. Think of Pavlov and his dogs. In his famous experiment he created an inferential association in the dogs’ minds between a bell and dinner. Hearing the bell thus set off salivation in expectation of food. The bell didn’t cause the salivation (or it wasn’t the ultimate cause), the connection was in the mind of the dog. The hearing of the bell set off a basic thought process which brought on the salivation. The dog inferred from experience, manipulated by the experimenter, that food was coming.

Mercier and Sperber approvingly quote David Hume’s common sense ideas about inference and its widespread application. Inference, he recognised, was a much more basic and universal tool than reason, and it was a necessary part of the toolkit of any sentient being. ‘Animals’, he wrote, ‘are not guided in these inferences by reasoning: Neither are children: Neither are the generality of mankind, in their ordinary actions and conclusions. Neither are philosophers themselves, who, in all the active parts of life, are, in the main, the same with the vulgar…. Nature must have provided some other principle, of more ready, and more general use and application; nor can an operation of such immense consequence in life, as that of inferring effects from causes, be trusted to the uncertain process of reasoning and argumentation’.

This is a lovely example of Humean skepticism, which flies in the face of arid logicalism, and recognises that the largely unconscious process of inference, which we would now recognise as a product of evolution, a basic survival mechanism, is more reliable in everyday life than the most brilliantly constructed logical systems.

The point is that we make inferences more or less constantly, and mostly unconsciously. The split-second decisions made in sport, for example, are all made, if not unconsciously, then with an automaticity not attributable to reason. And most of our life is lived with a similar lack of deep reflection, from inference to inference, like every other animal. Inference, then, to quote Mercier and Sperber’s gloss on Hume, is simply ‘the extraction of new information from information already available, whatever the process’. It’s what helps us slip the defender and score a goal in soccer, or prompts us to check the batteries when the remote stops working, or moves us to look forward to break-time when we smell coffee. It’s also what wags your dog’s tail when she hears familiar footsteps approaching the house.

There’s a lot more to be said, of course…

Written by stewart henderson

December 3, 2019 at 9:53 pm

nothing so simple? the gambler’s fallacy

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Humans are capable of reasoning, but not always or often very well. Daniel Kahneman’s famous book Thinking, fast and slow provides us with many examples, and not being much of a clear thinker myself, where probability and all that Bayesian stuff is concerned, I’ll start with something really simple before ascending, one day, to the simply simple. And not being much of a gambler, I’d never heard of the gambler’s fallacy before. It appears to be a simple and obvious fallacy, but I’m sure I can succeed in making it more confusing than it should be.

The fallacy involves believing that what has occurred before might dictate what happens in the future, in a particular context. It’s best explained by the tossing of a coin. With a fair coin, the probability of it landing tails up, on any toss, is .5, given that, in probability language, absolute certainty is given a value of 1, and no possibility at all is given 0. The key here is what I’ve italicised – the fallacy lies in believing that the coin, as if it’s a thinking being, has an interest in maintaining a result, over many tosses, of 50% tails – so that if results skew towards zero, say after 6 heads results in a row, the probability of the next toss being tails will rise above .5. 

Put another way: assuming a fair coin, the probability of it landing heads on one toss is .5. That should mean that over time, with x number of tosses, assuming x to be a very large number, the result for a heads should approach 50%. So it would seem quite reasonable, if you were keeping count, to bet on a result that brings the average closer to 50%. That’s without imagining that the coin wants to get to 50%. It just should, shouldn’t it?

The clear answer is no. There can be no influence from the past on any new coin toss. How can there be? That would be truly weird if you think about it. The overall results may approach 50%, according to the law of large numbers, but that’s independent of particular tosses. If you look at it this way, creating a dependency, you decide to bet on a pair of tosses. It could be HH, TT, HT or TH. Those are the only four options and the probability of each of them is .25 (i.e .5 x .5). So you might think that, after two heads in a row, it would be wise to bet on tails. But this bet would still have a .5 probability of succeeding, and the result HHT, taken together, would be .5 x .5 x .5, which is .125 or one eighth, the same as all the other seven results of three coin tosses. The probability doesn’t change before each toss, no matter the result of the previous toss. 

So far, so clear, but it would be hard not to be influenced into betting against a run continuing. That’s not irrational, is it? But nor is it rational, considering there’s alway a 50/50 chance with each toss. It’s just a bet. And yet… I’m reminded of Swann in a A la recherche du temps perdu, as my mind clouds over…

Written by stewart henderson

November 17, 2019 at 2:19 pm

Posted in gambling, probability

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