Sleights of Mind
What The Neuroscience of Illusions Reveals About Our Everyday DeceptionsStephen Macknik and Susana Martinez-Conde
Husband and wife neuroscientists trying to make a name for themselves so came up with a contest for Best Illusion of the Year.
illusion website here
Went to a conference in Las Vegas and came across all the stage magicians there. Magicians basically do cognitive science experiments for audiences, manipulating attention and cognition. Magic tricks work because humans have a hard-wired process of attention and awareness that is hackable. These hacks are available for marketers, negotiators and students of interpersonal relationships.
Our brain constructs reality. What you see hear feel and think is based on what you expect to see hear feel and think. And your expectations are based on all yr prior experiences and memories. as long as everything chugs along as expected, with no surprises, your visual system will miss much of what is going on around you.
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Describes a neat trick magician on stage with beautiful girl in a wisp of a white dress. Says he's going to change it to a red dress. Drumroll then stage lights go red and everything white is now red. Anticlimax letdown. "Well, I said I would make it go red" Audience groans. Then flash of light and voila! she is wearing a red dress. What happens is attention diverted back to magician, then few sec blindness from flash. As that happens, a trapdoor opens and cables rip the dress, which is only held on by velcro, off the model, exposing another dress underneath.
Make a coin disappear: guy just pretends to transfer; the coin is shiny and flashed in lights to leave an after-image, which our brain then uses to fill in the image - we expect to see a coin in left hand so we see it there; uses a whole lot of cues to reinforce the suggestion. The right hand holding the coin relaxes, the left hand which supposedly getting the coin tenses. Eyes follow the movement. Subtly shifts body as if taking up the weight of a coin on left side.
Magician 'Magic Tony' wears a dorky red fish tie ("I just wear it for the halibut") and leopard print shoes ("It took two leopards to make these but it's ok because they were babies.") Basic lesson: magic is about entertaining the audience - methodology comes second. Does a trick where apparently puts a card in middle of the deck, but marks spot with little finger and a cut brings it back to top. Our eyes are very bad at resolving detail unless it's right in centre of your vision. So all magician has to do is distract your attention for a second and you don't notice fine detail. A variation of this is where he pushes card into middle of deck, pushing surrounding cards towards you, strongly reinforcing your impression that the card is going in there. But in fact he tilts deck slightly, disguising fact that is lifting the top card and sticking your target card beneath that. Then you don't discern a 'double lift' where top 2 cards lifted as if one, and again your brain doesn't see enough detail to realize there are 2 cards there. This then leads to another refinement. "Let me show you that again" Drops the double cards back on top of deck. You think your card is on top, and he puts that card into middle of deck, which leaves target card on top.
How does magician saw a woman in half? Exploits our brain compulsion to fill in details. We 'see' head and feet of one woman lying flat, the illusion emphasised by outline of woman painted on the box, but it's really two separate women.
MC Escher's paintings of impossible staircases etc show how our eye can only concentrate on one small area at a time. Peripheral areas blur. Our mind constructs a reality by sewing together multiple local perceptions.
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Also see this with Mona Lisa. When you look directly at her mouth, there is no smile. You can only perceive it when you look away from her mouth. This is because each eye has 2 distinct regions for seeing the world. The central area, the fovea, is where you read fine print and pick out details. The peripheral area surrounding the fovea, is where you see gross details, motion and shadows. When you look at Mona Lisa's eyes (which is where we normally look when we look at another person) peripheral vision picks up the cheek shadows which enhance her smile. But if you concentrate on the mouth, you don't get the shadow effect.
We have a 'spotlight of attention', restricting how much information you can take in. When you attend to something, it is as if your mind aims a spotlight on it, and you actively ignore everything happening around your spotlight. Also have 'joint attention' where you point at something either directly with finger or indirectly by gaze, to indicate to someone else. Babies older than 14 months can understand this, as can dogs, but not chimpanzees. Magicians exploit this by directing your attention away from what their hands might be doing.
In magic show you have a huge task trying to peel away all layers of misdirection and figure out what you should be paying attention to. But the harder you try the harder it gets. The more you concentrate the more your focus is on area magician wants you to look at, where nothing particularly interesting is happening. All the areas around your focus of attention - where all the real action is going on - are conveniently suppressed by your own brain.
Called 'sensory capture' and partic when one object moving, such as Penn and Tellers juggling balls. The one you notice first becomes the salient one, suppressing attention on other. Magician then adds to the confusion with his patter, which sets your brain generating an internal monologue as you try to make sense of what is happening. The patter often includes comedy, laughter, corny puns and jokes. It's hard to watch the details of a trick if you're cringing or rolling your eyes.
We use mirror neurons to understand the actions and intentions of others. You mimic other's actions and use that simulation to see what you would feel when doing that. Your brain makes a prediction and runs a simulation, usually completely subconsciously. But a magician can fake an action he isn't really performing, and your mirror neurons feed you false assumptions. Magician raises a glass to his lips - you assume he's taking a drink, but is he transferring an object from hand to mouth or vv? Or the magician may turn his head and body toward some object, prompting you to follow the gaze.
Multi-tasking is a myth. Dan Simons 'Gorillas In Our Midst' video showed that we can look right at something, and even though our retinas take in the information, if the brain is paying attention to something else, we aren't aware of it. Further experiments with people walking, talking on cell phone, didn't notice a clown on a unicycle pedal up to them, circle around them and ride off. Research shows that you can't simultaneously give full attention to the visual task of driving, and the auditory task of talking and listening, even when using a hands free device. Same thing doesn't happen when talking to a passenger in car because they see what you see and adjust talk volume and level to what is happening outside. We have evolved to focus. Magicians exploit this divide-and-conquer by forcing you to split your attention so that you cannot concentrate fully on any one part of what is going on.
Rubber hand illusion. Get a fake hand from Halloween shop. Put it on table,put your left hand up on table beside it and put your real right hand in your lap. Then get a friend to brush gently on both hands on the table. You will quickly start to believe that you are feeling the brushing motion on both hands. Then when someone hits the fake hand with a hammer you will feel real fright and sometimes pain.
Using semantics to create false memory: Magic Tony calls 2 people onstage. He explains that before lecture started he got them to help him with a trick. Told the audience that he'd asked the man to think of a card and hold the memory of that card in his head until asked. And he'd got the woman to take a card from the deck and put it in her pocket unseen. Now, onstage, he asks guy what the card was he was thinking of? Jack of Spades. Asks woman to take card from pocket; sure enough it's the Jack of Spades. (This was at a psychology conference where magician lecturing, and the 2 helpers were other scientists, so not set-up stooges). All looks quite amazing. But, Magic Tony reveals what he actually said and did. To the guy, he showed the Jack of Spades and told him to remember. But once on stage, when Magic Tony omitted that bit, it seemed close enough approximation of what had happened that it became, to the guy, the true story. Similar thing with woman: Magic Tony actually presented deck of cards in a way that forced her to take J of C, but when he gets her on stage he tells the story in a way that implies she had a lot more freedom to pick.
Our mind uses prediction as labour saving device. Brain is constantly comparing incoming information with what it already knows, expects, believes. It's only when something unexpected appears that auto-pilot disengages. You walk down the street expecting the pavement to stay level; it's only when step off into road which is three inches lower, that you get a surprise. That's a trivial example, but auto-pilot can have major drawbacks. NASA put commercial pilots into simulator and had them do a series of boring routine landings. On some of the landings a large passenger aircraft parked on the runway. A quarter of the pilots 'landed' on top of the other plane: they never even saw it because they expected the runway to be clear.
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People easily accept their own assumptions, and they believe information that they have learned for themselves. They don't believe what conjuror tells them because he's here to trick them. Magician James the Amazing Randi goes on stage to illustrate. Audience assumes he is looking at them, but he tells them that they are just a blur of faces, because he needs to wear corrective glasses, and look - there are no lenses in these glasses - as he pokes his fingers through the frame. You assumed that they were normal glasses because that is what you expect.
We do this because thinking is expensive, and our brain takes shortcuts wherever possible. Thinking takes time and attention away from other tasks, like finding food and mates and avoiding cliffs and saber-toothed tigers. The more that you can assume, the more you can concentrate on current goals and interests. So when a magician tosses a coin into the air 3 times with right hand then mimes tossing it to his left hand, closing that hand as if it has caught the coin, our mind assumes that it saw the coin arcing through the air when in fact it never left the magician's right hand. The magician gives you all the cues - his head and eyes follow the expected trajectory - and your mind fills in the gaps with what it expects to see. We do the same thing to a dog, teasing it by pretending to throw a stick - the dog chases after it even though it never left your hand. During the magic trick you are as easily duped as the dog was.
Priming: answer these questions out loud: What color is snow? What color are clouds? What color is whipped cream? What color are polar bears? What do cows drink? If you said cows drink milk, you were primed by your previous answers to choose something white (cows drink water). Experiments confirm: give people jumbled sentences with words about old age, and they walk slower down corridor afterwards. Get Asian American girls to do maths test. Split into 3 groups. Use jumbled sentences to remind first group that they are girls. Remind second group they are asian. First group does worst (girls stereotype that bad at maths). Second group does best, because everyone 'knows' asians are good at maths. Control group scores in the middle.
Simple trick to illustrate. Mind read someone: Start by telling them the trick works best on groups of 3 or 7. This is totally untrue because it is always done 1 on 1, but you want to subconsciously 'prime' them with these 2 numbers. Ask them to choose a number between 1 and 50, but it has to be double digits, both of them odd numbers, and one number larger than the other. (Get them to write it down and check that meets the 3 requirements). That gives 8 possible numbers, but because you primed them at start, almost everyone chooses 37.
Our priming assumptions can be dangerous. Hunters primed to look for deer mistake a human in bush for the expected quarry. Motorists primed to look for other cars are oblivious to motorbikes and cyclists. The Gorillas in the Midst works because don't expect to see the animal on basketball court.
Magicians find kids very hard to fool or impress, because they haven't built up expectations of how the world works. A coin disappears - so what? Adults have learned to focus, to tune out irrelevant and unimportant, but kids try to pay attention to everything because haven't yet learned what is important. They are impressed by some things, like taking a coin out of someone's ear, because they know that that doesn't happen in their world. But it takes years of constant study for a child to work out what to expect from the world and the people around them.
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Turns out that introspection is a terrible way to figure out 'truth'. Introspection does not provide a way of understanding what is going on in your head. Instead, what it does is rationalise. We 'confabulate' (make things up) to justify what is happening in to us. A lot of studies have shown this. Show guys two pics of women of similar attractiveness and ask which they prefer. Then secretly switch pics and ask them why they prefer that woman, (unaware that it isn't actually their choice). They come up with stacks of reasons - one guy said he preferred blonds, despite fact that woman he chose was brunette. Another said he liked the woman's necklace, although his original choice didn't have one.
We have a (completely unjustified) belief in Free Will. For example in the West we don't have arranged marriages; we find our own mate(s). Yet we are constrained by geography - most people marry either their high school or uni sweethearts.
We feel like we're free. The huge best-seller The Secret with it's "Believe you will get what you want, and it will come" philosophy.
It's cognitive dissonance - our brains suppress info that contradicts our emotional position. We make a sub-optimal (dumb) decision for our kids, then stick to it 'for consistency'. we look down on people who live in another city because they have a competing sports team. History is written by the victors, and this is true within our heads as well.
Harvard psychologist Daniel Wegner The Illusion of Free Will says you look at an apparent causal sequence (magician saws a woman in two) which obscures a real causal sequence (the box is rigged so that the saw blade never touches her). You don't perceive the real thing even though the apparent sequence violates common sense and you know it's impossible. In the same way we look at things that we do and think of a way or reason we could have chosen to do it. Our brains are correlation machines, as magicians prove to us over and over by presenting us with impossible events which nevertheless convince us. Because we have the ability to connect cause and effect there is no evolutionary pressure to expend precious brain resources monitoring every step.
Free will illusion: go to a restaurant, you were going to order a shrimp entree but guy beside you orders it before you. You don't want to look like you're copying him so you change your order.
If you want to expose the illusion of the Ouija board, just blindfold the players - their spelled out messages will be gibberish.
Miser's Dream trick (multiple coins drop loudly into a bucket) illustrates the way our brain cause-and-effect power can be hi-jacked. The magician flashes a coin that he has 'plucked out of the air' and then drops it in bucket. Clunk. Then several more coins do same thing. But he only has one coin concealed in right hand which he repeatedly shows, and it's the many coins hidden in his left hand that drop in bucket. Extreme cases: Aztecs believed human sacrifice necessary for sun to rise each day - for them it worked every time.
We remember the things we do far easier than noticing what others do, so we are easily convinced that we are doing a disproportionate share of work.
"Gambler's fallacy": people have illusion that knowing past helps them predict future - so choose lotto or roulette numbers based on what comes up most, or what is 'due' to come up.
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Suggestion alters brain function. Placebos - a sugar pill will make you feel better, nocebos - a witch doctor can make you feel worse, meditation, magic tricks, hypnosis. Don't cure cancer, but change way brain works. About 10 -15% adults hypnotizable. 20% are totally resistant. Up to about age of 12, 80 - 85% of children are.
Scams bypass our logic circuits: The Pigeon Drop where guy 'finds' a flash looking pearl necklace in toilet of a gas station. Then phone rings: guy says he's lost necklace that he was going to give wife for wedding anniversary. Oh you've found it? Great I'll give you $200 reward. But 'finder' can't wait because has to go to job interview. Tell you what, I'll split the reward with you. So gullible guy takes $100 out of till, 'husband' never turns up, and it turns out the necklace is $2 shop fake. Sports Prediction: you get email from guy offering to predict outcome of game or box match. Not asking for anything, but demonstrating his power. This goes on for several weeks, all predictions correct. Then invites you to share in big bet coup. But turns out that he has started with big pool of email addresses and simply sent A or B predictions to all, each week only sending new predictions to previous winners.
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When you start to learn a complex skill, whether magic trick or dancing, first do it with top level of brain, constantly paying full attention, often losing track. But as learn skill the command sequences move toward automatic, and doesn't have to pay as much conscious attention. For the dancer that means he can chat or improvise while dancing. For a magician, it means difference between success and failure of a trick - if magician has to think about what he's doing he'll draw attention to the bit he's worrying about, and the audience will notice.
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