by Ian Leslie
Joan Vickers, a cognitive scientist who studies the eye movements of sportspeople, hypothesises that Fitzgerald is using ‘predictive control’, a skill we all have, but one that Fitzgerald has honed through years of experience of the game. As the ball approaches him, he takes a mental snapshot of it, which his subconscious then instantly compares to a vast library of memories drawn from years of playing and observation. As a teenager Fitzgerald worked as a ballboy for six seasons, and Vickers thinks that the thousands of passes he witnessed from the sidelines left him with a catalogue of impressions most athletes take years to accumulate. By matching his snapshot with the memory of all these other passes, Fitzgerald’s brain is able to conjure up a picture of where the ball will go. He can then work out how to put himself in position to catch it – without looking.10
Though Fitzgerald has an exceptionally refined skill in this regard, he’s using a feature of the brain that we all share. In the words of Chris Frith, a cognitive neuroscientist, the brain ‘actively creates pictures of the world’. Rather than trying to interpret every new thing it sees as if encountering it for the first time, the brain makes a series of working assumptions about what a chair looks like, or a person, and where that ball is going to be, then makes predictions – best guesses – about what’s before us. It compares its expectations with the new information coming in, checks for mistakes, and revises accordingly. The result, in Frith’s striking formulation, is ‘a fantasy that collides with reality’.
Our pro-active, interventionist cognitive system works extremely well most of the time – it has to, otherwise we couldn’t have survived as a species. But it can be fooled. The cognitive psychologist Gustav Kuhn recorded people’s eye movements while they watched a video of a magician performing the Vanishing Ball illusion, in which a ball thrown into the air seems to disappear mid-flight. The magician tosses the ball straight up into the air and catches it a few times. On the final throw, he only pretends to toss the ball, secreting it in the palm of his hand. As he does so, he looks to the sky, as if tracking the rise of the ball into thin air. This last detail is significant. Half the spectators were shown a version of the trick in which the magician looked at his hand instead of skyward on the final throw, and most of them spotted the trick. The spectators who succumbed to the illusion were being led by the movement of the magician’s head and eyes. These participants reported that they’d actually seen the ball leave the top of the screen. The eye-tracking analysis, however, showed that on that final, deceptive throw, their eyes didn’t even go to the top of the screen but stayed fixed on the ball. In other words, they had such strong expectations of where the ball was going to be that they hallucinated it.
Magicians, architects and artists have known about how to exploit the quirks of our perceptual system for millennia. The platform on which the mighty pillars of the Parthenon stand is not straight, but curved; its architects knew this is the only way to obtain the effect of a straight line. When magicians misdirect us away from their method and towards their effect, it’s our attention they’re manipulating, not our gaze. These bugs can occasionally cause disasters, when the brain directs our attention to the wrong things, overriding the reports of the senses. Time and again, under conditions of high visibility, and with no evidence of mechanical failure, drivers and pilots crash into obvious obstacles. In an experiment using a flight simulator, commercial airline pilots were asked to land a Boeing 727. On some approaches, the image of a small aircraft was unexpectedly superimposed onto the runway. Two out of eight pilots blithely continued with the landing manoeuvre as if the runway was clear.
So far we’ve talked only about vision, but the principles of cognitive self-deception apply elsewhere. We are deceived about our own bodies, for instance. Although we’re rarely aware of it, we are constantly monitoring information about the position of our bodies, and unconsciously making adjustments. When you lift your left arm you subtly shift some weight to the right side of your body to maintain balance and avoid listing to one side. The sensory feedback we receive about our muscles, joints and skin is known as proprioception, but most of us barely know it exists, because the brain makes our normal movements feel effortless.11 We vastly underestimate the mental sophistication and effort required just to stand still, or pick up a fork, let alone walk along a crowded street without colliding with people.
Our experience of when things are happening is partly illusory too. If you’re touched on your nose and your toe at precisely the same moment, the signal from the toe will reach your brain one tenth of a second after the signal from the nose, because it has further to travel along the body’s nerve fibres to the brain. But you will experience the touches as simultaneous, because the brain puts the first signal – from the nose – on hold while it waits for any other signals to arrive. When the toe signal arrives, you get the feeling of ‘now’. We all live at a slight lag from reality, and tall people experience a slightly longer lag from reality than short people, simply because the distance from toe to head is greater, which means the brain takes longer to check on all the signals. David Eagleman recounts that in the early days of television broadcasting, engineers worried about the problem of keeping audio and video signals synchronised. Then they accidentally discovered that they had around a tenth of a second’s grace; as long as the signals arrived within this window, viewers wouldn’t notice a thing. Their brains would automatically resynchronise the signals.
The world we perceive is also shaped by our desires. In 1947 Jerome Bruner and Cecile Goodman found that children consistently judged coins to be bigger than identically sized cardboard circles. The monetary value of the coins was influencing how big they perceived the dimensions to be. Tellingly, children from poor families perceived the coins to be bigger than children from affluent families. In a more recent study, psychologists from New York University asked students to estimate the distance between their own position and a full bottle of water on the table at which they were sitting. Beforehand, they fed some of the students a diet of pretzels to make them thirsty. The thirsty students judged the bottle to be closer than the other students did. Another study revealed that hills appear steeper to us than they actually are, and that this tendency is exaggerated when the observer is old, unhealthy, or wearing a backpack. This is self-deception rather than simple misjudgement. When participants in these studies are asked to judge the hill’s incline by adjusting the slant of a movable board with their hands (without looking at their hands) they got it right. Psychologists call this phenomenon ‘wishful seeing’.
Imagination, said Coleridge, is ‘the living power and prime agent of all human perception’, a sentiment echoed by Charles Darwin when he asserted that there could be no true observation of the world without speculation. Beginning at the most fundamental level, we are engaged in a continual negotiation between our expectations and desires about the world, and the world itself, between imagination and reality. Why does our brain deceive us about so much? Partly because it needs to fill in the gaps left by our sensory organs, but also because without an automatic ability to interpret and organise the incoming chaos of signals we would drown in them, becoming slaves to our impulses. Some brain-damaged people cannot help but act on everything they see. If they see a glass they must drink from it; if they see a pen they must write with it. Through the use of what Frith calls ‘controlled fantasy’ our brain screens out what it deems irrelevant and helps us to establish what’s important to us – amidst all the noise and chatter at a party your name leaps out at you.
For the brain, truthfully depicting reality accurately comes second to survival. Of course, the two objectives are very much aligned, but not completely. We’re less likely to kill ourselves attempting that hill if we think it’s steeper than it is, and we’re more likely to make an effort to reach something desirable if it seems nearer than it is.
Choice Lies
In 1983, Benjamin Libet of the University of California asked participants in an e
xperiment to make a movement at an arbitrary moment decided by them (they were instructed to flex their wrist ‘freely and capriciously’), and to note the precise time, using a specially designed clock, at which they decided to make their move. As they did so, Libet monitored their brain activity. He found that the brain prepares the body to move several hundred milliseconds before the person consciously decides to move. The person’s conscious intention seemed to be, literally, an afterthought.12 We like to think that we deliberate about what to do, then do it. But Libet’s experiment, and others that followed, suggest that most of the time we act first and invent reasons, feelings and motivations afterwards.
In another, rather eerie experiment, designed by the psychologist Daniel Wegner, you participate with a companion who is apparently doing the same experiment but who is actually an assistant of the experimenter. You and your companion sit at a computer screen and both of you place a finger on a shared, specially designed mouse. There are lots of objects on the screen, and through earphones someone tells you to move the on-screen pointer towards one of them. You have the thought, and then you move the mouse. If your companion moves the mouse as you are having the thought, but before you have actually moved your arm, then you will believe that you moved the mouse. You’ll feel as if you chose to do something that somebody else did for you (this illusion works if the interval between having the thought and the mouse moving is about one and a fifth seconds or less).
Wegner believes that our feeling of free will is nothing but a trick of perspective – a deception practised by the brain. A conscious ‘decision’ is merely a story we tell ourselves to explain what has happened to us, or what our bodies have already executed. This is a deeply contentious position, although many neuroscientists agree with him. There is certainly a huge amount of experimental evidence that our unconscious brain guides and determines many of the everyday decisions we think of as conscious ones. When you choose a brand of toothpaste or reject someone for a job you may be doing so for reasons of which you’re completely unaware – the unconscious associations you have with a brand name, the job candidate’s gender. What’s certain is that you’ll spontaneously come up with a plausible reason: the toothpaste’s plaque-reduction system, the interviewee’s lack of experience.
Two cognitive scientists from Sweden named Lars Hall and Petter Johansson devised an experiment that relies on a card trick they were taught by a professional magician. The researcher holds up two photographs, each with a different face on it, and asks the subject to choose the one she finds more attractive. The researcher lays both pictures face down and slides the chosen photograph over to the subject – except he doesn’t. Using a sleight-of-hand technique he covertly swaps one picture for the other, so that the picture the participant ends up with is the one she didn’t choose.13 You might expect the subject to take one glance at the photo in her hand and protest to the researcher that this isn’t the man she chose, and indeed in some cases that’s exactly what happened. But in most trials, the participants didn’t appear to notice. This alone would make the experiment interesting. The most telling part, however, came when the subjects who had accepted the ‘wrong’ card were asked how they had made their ‘choice’. They unhesitatingly offered up elaborate explanations of what had attracted them to that person’s eyes, hair, or bone structure.
One classic experiment was conducted in a park in British Columbia, Canada. A female assistant with a clipboard approached young men in the park and asked them to take part in a survey on creativity. After writing down their answers, she suggested that maybe they might like to discuss the results with her later, and wrote down her number for them. The researchers tallied how many of the men called her later and asked her out. The clever part of the experiment was that the researchers varied the situation the men were in when approached. Half of them were on a terrifying footbridge spanning a deep gorge. As these men talked to the woman they were holding tight to the flimsy handrail as the bridge swayed in the breeze. The other group of men were sitting safely on a park bench. The question the researchers were interested in was, which group of men would be more attracted to the woman?
You might wonder why on earth it should make a difference whether they were approached on the bridge or the bench; after all, it’s the same woman. Yet sixty-five per cent of the men on the bridge called to ask the woman on a date, compared to thirty percent of the men on the bench. The reason for this is that the brain can pursue its mission to explain with a little too much zeal. When the men on the bridge took the woman’s number, their hearts were pumping rapidly, they were perspiring, and a little short of breath. They would have recognised to some extent that these symptoms were down to their physical situation, but even so, they misattributed some of their arousal to attraction to the woman. The sense-making part of their brains had gone into overdrive and created a surfeit of explanation for what was going on. As a result the men became much more likely to tell themselves they had a crush on the woman, and more likely to call her afterwards. So there you are: if you want to ask a stranger out, wait until they’re in physical danger and seize your moment.
Like our perception of the physical world, our perception of why we do things is a fantasy that collides with reality. This description would have made sense to Freud, of course, who believed that we are deceived about the nature of reality because we fundamentally deceive ourselves about who we are. We fantasise that we know what we want out of life when in reality we are divided into warring factions, each wanting something different. Amongst academic psychologists at least, Freud’s ideas fell deeply out of fashion after he died. His arguments were based more on intuition than evidence, and his gothic vision of the unconscious as a realm of repressed sexual desires remains deeply idiosyncratic. But in recent decades, neuroscientists have concluded that he got at least two very important things right: our psyche is deeply divided, and our conscious actions are deeply influenced by sophisticated mental processes of which we remain unaware, day by day. All of us are engaged in an act of creative self-deception to maintain the fiction that we know why we do the things we do.
The Lie of ‘I’
In 1960 a young graduate student called Michael Gazzaniga joined the laboratory of the great neurologist Roger Sperry. Gazzaniga was overjoyed to have landed a job under Sperry, who was the first to discover that the brains of some animals, including ours, are split into two systems, left and right, each with different responsibilities. If you stare at a fixed point in space, like a dot on the wall in front of you, everything to the left of the dot is projected to the right half of your brain, and vice versa. Each hemisphere receives nerve transmissions from the opposite leg and arm and picks up sound from the opposite ear. Nobody knows why the signals cross over – the official scientific explanation is pretty much, they just do – and in the normal brain it doesn’t make much difference where the information lands because the connecting pathways between each half-brain are intact.
In 1961 Sperry got a call from a former colleague, the neurosurgeon Joe Bogen, who told him that he was about to perform a radical new operation on a patient suffering from epilepsy. Epileptic seizures always start in one part of the brain and then spread to the surrounding tissue. A minor seizure can spread to the entire brain, causing the person to lose consciousness, fall to the floor and writhe uncontrollably. To stop the seizure spreading from one half of the brain to the other, Bogen proposed a severing of the thick bundle of nerve fibres, known as the corpus callosum, that connects the two hemispheres. Sperry sent his protégé Gazzaniga over to Bogen’s lab, to perform tests on the patient before and after the operation.
Given that nobody was quite sure what the corpus callosum was responsible for, or how the two halves of the brain interacted, Bogen’s proposed operation was risky. But he knew Sperry had performed this operation on animals with no apparent ill effects, and he knew that his patients, some of whom suffered from severe, life-ravaging epilepsy, were desperate to tr
y something. William Jenkins, a smiling, chipper forty-eight-year-old, had volunteered to be first to undergo the operation. Bogen had first met him when Jenkins was admitted to the emergency room of Bogen’s hospital in the middle of a severe fit. Jenkins suffered frequent, punishing convulsions and dangerously sudden losses of motor control, which effectively prevented him from living anything close to a normal life, and he had been told there was no cure for his condition. He knew that Bogen’s solution was something of a leap into the unknown, but he and his wife told the surgeon that they were eager to go ahead. ‘You know,’ said Jenkins, ‘even if it doesn’t help my seizures, if you learn something it will be more worthwhile than anything I’ve been able to do for years.’ In February 1962, after practising the operation half a dozen times in the morgue, Bogen severed Bill Jenkins’s corpus callosum.
It worked. Jenkins recovered strongly from the surgery and was soon feeling something like his old self again, his seizures greatly alleviated. But were there really no side-effects? Gazzaniga asked Jenkins to stare at a spot on a screen while he flashed images just to the right or just to the left of it. The images came and went quickly enough that the patient couldn’t move his gaze, so when a picture of a hat was flashed just to the right of the spot, it was processed by his left hemisphere. When Gazzaniga asked, ‘What did you see?’ Jenkins had no difficulty in identifying the hat. But if the same image was flashed on the left side of the spot, he didn’t know what to say. The image was being processed by the right hemisphere, which doesn’t have the power of speech.
It’s not as if the right brain hadn’t seen anything. Gazzaniga showed Jenkins a card with several images on it, and asked him to point with his left hand to the image that he had just flashed up on the screen. He had no difficulty doing so. The right hemisphere knew the answer – it could point – but was unable to communicate verbally. Normally, Gazzaniga realised, it could call out to the left hemisphere via the corpus callosum for help in finding the right word. But without it, nothing emerged from the patient’s mouth. In another experiment, Gazzaniga blindfolded Jenkins and asked him to hold an object like a comb or a coffee cup in his left hand. If he held it in his right hand he had no trouble identifying it. When transferred to the left hand, he was literally at a loss for words.
