Why We Lie: The Source of our Disasters

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That is, if your brain did not already contain a picture of what an apple was and how it could be eaten, you would not create motor plans to snatch the fruit, unless, perhaps, you had no knowledge of good manners and were so overcome with curiosity that you planned to seize and examine this strange thing.

What I had been taught all those years ago is now called the sensory-motor model of human action, whereas now we have the ideomotor model which ‘assumes that the starting point of actions are the intentions associated with them, and that actions should be mostly considered as means to achieve those intentions’.

If you want to understand another person (or yourself) you need to know not just what that person does but why he does it.

In short, our brain interprets the world, and our interpretations become our intentions in acting on the world. But, if our interpretations are only guesses about our world, how can we assess whether our actions are likely to be successful? Answer: with our Bayesian brains.

Thomas Bayes was an eighteenth-century Presbyterian minister and mathematician. He created a mathematical theorem concerning the probability of an event occurring changing as more information is accumulated. A famous example of Bayesian brains at work is that scene where people are looking up into the sky and asking, ‘Is it a bird? A plane? No, it’s Superman.’ In this case, the Bayesian brain is working out the probability of the hypotheses of, first, a bird, then, a plane, and, with the best evidence, Superman himself, a conclusion, all without conscious effort on the part of the observers. Computers can use Bayesian methods of calculating the probabilities that arise in very complex data. As a Presbyterian, Bayes would have been pleased that his statistical method is used in computers to filter out immoral spam. My computer manages to identify all those email offers of Viagra and penis extension, but, unfortunately, it cannot distinguish these from the emails from that very august establishment The Sydney Institute in the city of that name. My Bayesian brain knows the difference, but my Bayesian computer does not.

We can make grave errors in deciding the probability of a particular event, but, according to Chris Frith,

Our brains are ideal observers when it comes to making use of the evidence from our senses. For example, one problem our brain has to solve is how to combine evidence from our different senses. When we are listening to someone, our brain combines the evidence from our eyes – the sight of their lips moving – and from our ears – the sound of their voice. When we pick something up, our brain combines the evidence from our eyes – what the object looks like – and from our sense of touch – what the object feels like. When combining this evidence, our brain behaves just like the ideal Bayesian observer. Weak evidence is ignored; strong evidence is emphasized. When I am speaking to the Professor of English at a very noisy party, I will find myself staring intently at her lips, because in this situation the evidence coming through my eyes is better than the evidence coming through my ears.

When I am lecturing, I make constant assessments of the probability that my audience is interested in what I am saying. When I am talking about how we operate in the world, the response from most people suggests that they have not encountered the idea that they cannot see reality directly, or that the brain calculates probabilities in making a guess about what might be going on. I find that my audiences listen with a degree of attentiveness that they do not show when I am talking about matters with which they are familiar. I found this even in an audience comprised of highly educated people who placed great value on education. These were the parents of students at a famous public school. I had been asked to talk about communication between parents and their children. To explain why communication so often failed I needed to begin by explaining how we operate as human beings.

I have given this part of my lecture many times. I usually begin with something which I acquired from Ian Stewart, the Professor of Mathematics at Warwick University, but which I now pass off as my own.

Standing in front of my audience and with appropriate gestures, I say, ‘As I stand here everything seems totally real. I’m here, you’re over there, and beyond you are the walls, and beyond that what I can see through the windows. But actually, that isn’t what is happening. I have no idea what is actually here. What is happening is that my brain has created a picture of what might be here, and then it has played a clever trick on me. It has persuaded me that, instead of the picture being inside my head and I’m all around it, I’m in the middle and the picture is all around me. The same thing is happening to you. What you’re seeing is a picture inside your head, but your brain has tricked you into thinking that you’re in the middle and the picture is all around you.’

I go on, ‘If we could take these pictures out of our heads like a photo out of a camera and hang our pictures on the wall so that we can all walk around and look at them, we would find that no two pictures were the same.’

The next part of what I say reveals in the audience’s reaction how little biology is taught in our schools, or taught in such a way that the students do not see the implications of what they have learnt. Most of my audience – even when they are medically trained – find what I say next amazing. I run through all the features of the pictures where there would be differences. In the structuring of the depth and distances in each picture there would be differences which relate to the environment in which the person had spent the first few months of his life when he was learning how to see. Babies do not just open their eyes and see. They have to learn how to see. The baby’s brain has to set up connections between the reactions of the baby’s retinas when light strikes them and those parts of the baby’s brain which can become the visual cortex. If this learning does not take place at the precise time when it needs to take place, the baby does not learn to see, and what would have been the visual cortex is taken over by some other cortical function. Just what connections are set up in learning to see depend on the environment the baby is in. Those of us who spent our early months in rectangular rooms learned to structure depth and distance differently from those babies who were in round rooms, like kraals or yurts, or those irregularly shaped spaces that some babies, like those of refugees in Darfur, spend their first months. The paintings by Australian aboriginal artists who grew up in the Outback pay little attention to parallel lines, right angles or perspective that dominate the structure of space by those of us who were put into rectangular rooms when we were born.

I usually follow this with an account of how we have to learn how to distinguish small things close up from large things far away. If in our first year or so we spend some time in large open spaces we learn how to make fairly good guesses about an object’s size and distance from us. From then on we can look down a long road and see a car in the distance coming towards us. However, few of us as small children spend much time looking down from the top of a tall building to the street below, and so, when as adults we go to the top of a tall building and look down to the street below, what we see are toy cars and not full-sized automobiles.

The next feature where there would be differences between our pictures is in colour. The world is not a colourful place. Colour is in the eye of the beholder, in the array of cones in the retina of the eye. There is no way of knowing whether what you call blue is the same as what I call blue. Some people, usually men, cannot see colour, or they confuse red with green. In my lectures I might refer briefly to the fact that there are not only huge variations in individual perceptions of colour but in the words we use when we talk about colour. The linguist Annie Mollard-Desfour is compiling Dictionnaire des mots et expressions de couleur (Dictionary of Words and Expressions of Colour). The first volume, Le Bleu (Blue) appeared in 1998, and the fifth Le Blanc (White) in 2007 with another six to come. In an interview with Laura Spinney for New Scientist she said,

There is no objective reality of colour. It’s an impression, a sensation which forms in the brain based on information sent to it by the visual apparatus. To label that sensation, to transmit it to others, we revert to familiar symbols. Colour words, perhaps more than any others, reflect a society: its values, its practices, its history. In Benin in west Africa, for example, men and women have different colour vocabularies. Searching for colour words in literature, the press or slang, as I do, you are forced to confront the enormous diversity in the way different cultures, different symbolic systems, view the world.

Not only do different cultures identify and name colours differently but the connotations of each colour differ markedly. For the French white means purity, cleanliness and honesty but to the Chinese it is the colour of mourning. To the French someone who is just beginning to learn a skill is blue, but to the English a novice is green. For the English a pornographic film is blue but for the French it is pink.

The biggest differences among the pictures we took out of our heads and hung on the walls would be in what each of us has noticed. No one ever walks into a room and sees everything. What we notice are those things that are significant to us. They are full of meaning. We notice the people we know, or the person we wish to avoid. We might notice an object that is strikingly different from anything we have ever seen, or something familiar but unexpectedly present. As Chris Frith wrote, ‘The brain constructs a map of the world. This is essentially a map of value. The map locates the objects of high value where I am likely to be rewarded and the objects of low value where I am not likely to be rewarded.’

What we happen to notice is determined by our past experience, and, since no two people ever have exactly the same experience, no two people ever see anything in exactly the same way.

When we look around we see a world that is appropriate to our size, a human-sized world. Mice move in a mice-sized world, and elephants in an elephant-sized world. Mice see what is important to mice, and elephants see what is important to elephants. The human-sized world we see appears to be very solid. Our body seems to be quite solid. However, we are made up of atoms, and atoms are not solid at all. There is a solid central core which is tiny. Far from the core are masses of electrons orbiting around the core. In his explanation of electricity in a booklet for non-scientists, David Bodanis explained how an atom is mainly empty space. The booklet we were holding would not slip from our hands because the electrons on the surface of our hands were shooting a powerful force field upwards, hitting the force field coming down from the electrons on the bottom of the booklet. This means that, although we think we are holding the booklet, it is actually hovering a small fraction of an inch above our skin.

Presumably, if our brain were capable of seeing reality directly, this is what we would see, along with all those elementary particles with the curious names like charm, strange, tau and gluon. When physicists talk of discovering such particles, what they have actually seen is not the particle itself, but a trace that the particle has left behind. From this, the physicists conclude that a particle has whizzed by. In much the same way, when we see a straight line of gently dispersing cloud in the blue sky above us, we conclude that a plane high up in the stratosphere has flown by. We live in a human-sized world. To see particles directly we would have to be in a particle in a particle-sized world. Then the Large Hadron Collider at Cern would be unnecessary for us to establish whether the Higgs boson actually exists, but, whatever we were, we would not be human beings.

My audience listened to this first part of my lecture with the kind of fierce attention we give to a speaker when we are being told something that we did not know but which we recognize as being of great importance to us. This kind of attention is different from the polite but bored attention we give to something we already know quite well. Later in my lecture I said something about teenagers and drugs, and immediately my audience looked bored. They knew more about drugs than they had ever wanted to know. What they wanted to hear was an account of how we perceive as it related to the difficult business of being a parent.

Why didn’t this group of well-educated people know how they operated as human beings?

Answer: because knowing this is both subversive and frightening, and it can challenge some of your most precious beliefs.

After my lecture I had quite a long discussion with the headmaster. I am sure he knew that what I had said was subversive. He did not charge me with this because he recognized that I had spelled out in detail the dilemma he faced in his work. He wanted his students to think for themselves, but he was expected by the parents and the school governors to foster in the students those ideas which would enable them to fit easily into a society for which the education they were receiving was a necessary qualification. He needed to encourage his students to develop their own ideas, but these ideas should not run counter to the ideas that their parents and the school governors wanted them to hold. He could have done what most parents and teachers do. They make it very clear to the children that their ideas are wrong, stupid and wicked. They have to give up their own ideas and accept those of the adults because the adults’ ideas are right, intelligent and good. When children do this, they become what adults call ‘good children’. As a result, many children grow up believing that, if they think anything which is different from what they have been taught to believe, there is something seriously wrong with them. They feel guilty when one of their own truths creeps into their consciousness, and they look for and follow those leaders who demand uncritical devotion. How else would people like Hitler in Germany in the twentieth century and Kim Jong Il in North Korea in the twenty-first century get such blindly obedient followers?

This was not the kind of education the headmaster wanted to give his students, but his was a high-achieving school. As he told me, the governors expected him to maintain this high standard; parents sent their children to the school in order that they do well, both at school and in their subsequent careers. Most of the children wanted to achieve, but some of the students took the need to achieve too seriously. They worked too hard and worried too much. He wanted to tell these students that such anxious effort was un necessary, and that they should enjoy their schooldays, but would the governors and the parents see this advice as being in the interests of the students?

Small children know that they see things differently from their parents. Some children manage to hang on to this knowledge and to value their own point of view, despite the authoritarian adults they encounter. Some lucky children have parents who take the child’s point of view seriously. When we take another person’s view seriously we are not necessarily agreeing with that person. A parent can say, ‘I appreciate that you have good reasons for staying up late, but I have good reasons to want you to go to bed now. In this particular situation my reasons are going to prevail. Go to bed now.’

When we take other people’s point of view seriously, we are implicitly acknowledging that our different points of view arise from the way we are as human beings. Many religious leaders talk about how important it is that we all accept people of other faiths, and there are many ecumenical gatherings of priests, rabbis, vicars, ministers and imams. In these meetings, are all these clerics saying that their different beliefs are of equal value? Or are they merely being polite to one another while secretly thinking, ‘I’m the only one that is in possession of the absolute truth and the rest of you are going to burn in hell’s fires’?

When the charge of being subversive is levelled at me by believers, I am always told that I am saying that all relative truths are equally valid. I immediately point out that I would not be so stupid as to say this. What I am saying is that we cannot help but have our own individual truths, but to show that our own truths are valid we have to test them by gathering evidence that this is so. This usually brings the discussion to an end, because those ideas which are claimed to be the absolute truths of a religion are usually the kind of ideas for which good evidence is hard to find.

There were no questions about religion after my lecture. Rather, parents wanted to know about their children’s future. My answers were not particularly comforting. I said that no one was in a pos ition to predict what the future of these students would be. The parents’ belief that success at school led to a successful career was based on the parents’ experience. They were assuming that the future would, more or less, be the same as the past. It is unlikely that the students saw the future in the same way as their parents did. Most children learn a good deal about climate change in school, so many of the students would probably know more about climate change than their parents did, and they probably did what all of us do when we hear of some likely but unpleasant outcome of climate change. We calculate what age we will be when it is predicted to occur. It is not so easy for teenagers to comfort themselves with the thought, ‘I’ll be dead by then.’ On the BBC Radio 4 programme Leading Edge the scientist Richard Sellay, talking about how climate change will affect wine production in Britain, said, ‘By 2080 the temperature in summer England is going to increase by 4.5 to 5 °C. So there’ll be Riesling on the slopes of Snowdonia, Manchester Merlot, and Sheffield Shiraz.’

This sounds all very jolly, but, if this prediction is close to being correct, there will be a steady warming of the planet over the students’ lifetime. However, there are so many variables involved that scientists cannot make precise predictions. Most scientists were surprised when, in the summer of 2007, the Northwest Passage became clear enough for shipping to pass through it. That the ice was melting was known, but that it would melt so quickly was not expected.