Paranormality: Why we see what isn't there (9 page)

Ramachandran’s work has important practical, as well as theoretical, implications. The majority of people who have had an arm or leg amputated often continue to feel excruciating levels of pain from their phantom limb. Ramachandran wondered whether this pain was due, in part, to their brains becoming disoriented because they were continuing to send signals to move the missing limb but then not seeing the expected movement. To test his theory, Ramachandran and his colleagues ran an unusual experiment with a group of amputees who had lost an arm
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The research team built a two-foot-square cardboard box that was open on the top and front. They then placed a vertical mirror along the middle of the box, thus separating it into two compartments. Each participant was asked to place their arm into one of the compartments, and then orient themselves so that they could see a reflection of their arm in the mirror. From the amputee’s perspective it appeared as if they were seeing both their actual, and missing, arm. The amputee was then asked to carry out a simple movement with both of their hands at the same time, such as clenching their fists or wriggling their fingers. In short, Ramachandran’s box created the illusion of movement in their missing limb. Amazingly, the majority of the participants reported a reduction in the pain associated with their phantom limb, with some of them even asking if they could take the box home with them.

It is one thing to convince people that part of them inhabits a dummy hand or tabletop, but is it possible to use the same idea to move a person out of their entire body? Neuroscientist Bigna Lenggenhager, from the École Polytechnique Fédérale de Lausanne in Switzerland, decided to investigate
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If you were to take part in one of Lenggenhager’s studies you would be taken into her laboratory, asked to stand in the centre of the room and fitted with a pair of virtual reality goggles. A researcher would then place a camera a few feet behind you and feed the output into your goggles, causing you to see an image of your own back standing a few feet in front of you. Next an animated stick would appear on the image in front of you and slowly stroke your virtual back. At the same time the researchers would sneak up behind the real you and slowly stroke your back with a highlighter pen, being careful to ensure that the actual stroking matched the virtual stroking. The experimental set-up is identical to the dummy hand and paintbrush study, but with the ‘virtual you’ taking the place of the dummy hand and a highlighter pen replacing the paintbrush. In the same way that stroking the dummy hand produced the strange sensation that part of you inhabited the hand, so Lenggenhager’s set-up resulted in people feeling as if their entire body was actually standing a few feet in front of themselves.
 

The dummy hand and virtual reality experiments demonstrate that the everyday feeling of being inside your body is constructed by the brain from sensory information. Alter that information and it is relatively easy to get people to feel as if they are outside of their bodies. Of course, people don’t have access to rubber hands and aren’t wired into virtual reality systems when they have out-of-body experiences. However, many researchers now think that this strangely counter-intuitive idea is essential to understanding the nature of these episodes.
 

BOX

MIRROR, MIRROR ON THE WALL

Neuroscientist Vilayanur Ramachandran and his colleagues have created a simple way of replicating Lenggenhager’s experiment without the need for a complicated and expensive virtual reality system
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In fact, you just need two large mirrors and your finger. Arrange the two mirrors so that they are facing one another and a few feet apart. Next, angle one of the mirrors so that when you look into one mirror you see the reflection of the back of your head (see photograph). Finally, gently stroke your cheek with your finger and look at the image in the mirror.
 

This rather unusual set-up replicates the illusion created by Lenggenhager’s virtual reality system. Your brain ‘feels’ your cheek being stroked, ‘sees’ a person standing in front of you being subjected to simultaneous stroking, concludes that ‘you’ must therefore be standing there, and constructs a sense of self that is consistent with this idea.
 

When he took part in the demonstration, Ramachandran felt as if he was touching an alien or android body that was outside his own body. Many of his colleagues felt similar sensations, with some of them reporting that they wanted to say ‘hello’ to the person in the mirror.
 

Set-up for the mirror experiment.

END BOX

At the start of this book I described how seeing psychologist Sue Blackmore on television made me realise how studying the supernatural could reveal important insights into our brains, behaviour and beliefs. Blackmore has investigated many aspects of the paranormal over the years, but much of her work has focused on the secret science behind out-of-body experiences.
 

Witchcraft, LSD and Tarot Cards
 

Sue Blackmore’s interest in the paranormal dates back to 1970 when she was a student at Oxford University and had a dramatic out-of-body experience. After several hours experimenting with the Ouija board and then relaxing with some marijuana, Sue felt herself rise out of her body, float up to the ceiling, fly across England, travel over the Atlantic, and hover around New York. Eventually she travelled back to Oxford, entered her body through her neck and finally expanded to fill the entire universe. Other than that it was a quiet night.

Upon her return to reality, Sue became fascinated with weird experiences, trained as a white witch, and eventually decided to devote herself to parapsychology. She was awarded a doctorate for work examining whether children have telepathic powers (they didn’t), went on several LSD trips to see if they would improve her psychic ability (they didn’t), and learned to read Tarot to discover if the cards could predict the future (they didn’t). After 25 years of such disappointing results Sue finally gave up the ghost and became a
 
sceptic. For many years she examined the psychology of paranormal experiences and beliefs, trying to figure out why people experienced seemingly supernatural sensations and bought into such strange stuff. Most recently she has turned her attention to the mystery of consciousness, focusing on the ways in which the brain creates a sense of self (although, rather disappointingly, the ‘Who Am I’ tab on her website delivers a straight biography).
 

Interview with Sue Blackmore

http://www.richardwiseman.com/paranormality/SueBlackmore.html

One of Blackmore’s early investigations tackled a question that comes up frequently when I speak about the paranormal – why do identical twins often appear to have a strange psychic bond with one another? Many proponents of psychic ability believe that this odd bond is due to telepathy. In contrast, sceptics argue that twins will often think in very similar ways because they have been raised in the same environment and have the same genetic makeup, and that such similarity will cause to them to make the same decisions and thus appear to read each other’s minds.
 

To help settle the issue, Blackmore brought together six sets of twins and six pairs of siblings, and conducted a two-part experiment
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The first part was a straightforward test of telepathy. One member of each pair played the role of the ‘sender’ while the other was the ‘receiver’. The sender was presented with various randomly selected stimuli (such as a number between one and ten, an object, or a photograph), and was asked to psychically transmit the information to the receiver. No evidence of telepathy emerged from either the twins or the siblings.
 

In the second part of the experiment, Blackmore asked the senders to transmit the first number that came into their mind, make any drawing that appealed to them, and choose which of four photographs to send. The results suddenly changed. As predicted by the ‘twin telepathy is due to similarity’ hypothesis, there was a sudden surge in the twins’ performance. For example, when asked to think of a number between one and ten, 20 per cent of the trials involving twins produced the same number compared to just 5 per cent of those with the siblings. For the drawings, the twins again scored well, exhibiting a 21 per cent success rate compared to the siblings’ 8 per cent.
 

 
      
In short, the evidence indicates that twin telepathy is due to the highly similar ways in which they think and behave, and not extra-sensory perception.
 

However, Blackmore is perhaps best known in
 
sceptical circles for her work explaining out-of-body experiences. She took as her starting point the notion that the feeling of being located inside your body is an illusion created by your brain on the basis of incoming sensory information. Then, in the same way that a rather weird set of circumstances involving a dummy hand or a virtual reality system can cause people to believe that they are elsewhere, Blackmore wondered whether an equally strange set of circumstances might cause people to think that they had floated away from their bodies. Sue focused her attention on two elements that were central to most OBEs.

The first principle can be illustrated with the help of the image below.
 

Fix your eyes on the black dot in the centre of the image and stare at it. Providing that you are able to keep your eyes and head relatively still you will find that after about 30 seconds or so the grey area around the dot will slowly fade away. Move your head or eyes and it will jump right back again. What is going on here? It is all about a phenomenon referred to as ‘sensory habituation’. Present someone with a constant sound, image, or smell and something very peculiar happens. They slowly get more and more used to it, until eventually it vanishes from their awareness. For example, if you walk into a room that smells of freshly ground coffee, you quickly detect the rather pleasant aroma. However, stay in the room for a few minutes, and the smell will seem to disappear. In fact, the only way to re-awaken it is to walk out of the room and back in again. In the case of the illustration above your eyes slowly became blind to the grey area because it was unchanging. This exactly same concept can result in the so-called ‘hedonistic treadmill’, with people quickly getting used to their new house or car, and feeling the need to buy an even bigger house or better car.
 

Blackmore speculated that this process was also central to OBEs. People tend to experience OBEs when they are in situations in which their brains are receiving a small amount of unchanging information from the senses. They are often robbed of any visual information because they have their eyes shut or are in the dark. In addition, they usually don’t have any tactile information because they are lying in bed, relaxing in the bath, or are on certain drugs. Under these circumstances the brain quickly becomes ‘blind’ to the small amount of information that is coming in, and so struggles to produce a coherent image of where ‘you’ are.