Recent research gives us a clue as to why yoga nidra and related meditation techniques are so valuable in relieving us of our mental blockages and allowing us to attain our full potential. These blockages are our old memories and impressions, and the effects they have on our whole personality. We know that memories deep in the mind and the emotions associated with them determine our ongoing mental and mood states and the way we interact with our world, but what can we do about them?
The memories of many of our past experiences - our samskaras - carry with them an unconscious emotional charge. In the animal kingdom this serves the crucial purposes of self-preservation and preservation of the species, and they are very active in us too. How does this work?
Because of the way the animal body and its brain are designed, it experiences pleasure from activities that protect it, such as food, warmth and comfort, and from behaviour that produces more of the species, such as sexual activity. Because these are pleasant the animal is attracted to them, and because memories of such experiences deep in the mind have those pleasant feelings attached to them, when the animal meets up with those things again it is attracted to them.
On the other hand, memories of experiences that threaten the well-being or reproductive urges of the animal, those that have caused pain and other discomfort in the past, such as physical damage by an enemy, or starvation, or a sexual rival, cause it to be repelled by those things when encountered again. Indeed, these memories are so powerful and so important that many are imprinted in the animal at birth in the form of instincts - a kind of species memory.
At the level of our animal body the storing of these emotionally charged memories is a good thing, but they cause us problems too. As human beings we are trying to evolve beyond the mere animal level of our existence and our identification with it. We are spiritual beings and our destiny is to transcend this identification with the body and its roles in life, but the memories and their emotional charges are holding us back. The body and those memories cause us to experience our world in inappropriate ways, to think about our world and the other individuals in inappropriate ways, to have destructive and addictive emotions, to make wrong decisions, and to behave in destructive and addictive ways. If we are to transcend the 'animal' and evolve as we should, we have to do something about them, but what?
What can we do about the power of our memories? What can we do with them that will free us from the animal urges they cause? Yoga is designed to do just this job. The majority of the physical techniques of yoga help to bring our deeply hidden memories with their emotions to the surface of the mind. Then the meditation practices give the memories a 'screen' onto which they are 'projected' so that we can become aware of them. According to the yogis, all we have to do is become aware of them in an unemotional state - the mental position of the drashta, witness or observer - the sakshi position as it is called in Sanskrit - and they lose their effect on us.
How does this happen? Surely they are still the same memories with the same emotions they were before we brought them up into our awareness! After we start to think of something else, don't they remain stuck down there in the unconscious mind? One would think so, but the experiences of the yogis over thousands of years, and of the psychotherapists and psychoanalysts of the recent hundred years tell us that this is not so, that they actually do lose their power to hold us back as soon as they reach the 'light of day' and are realized in a state of neutral emotion.
Until now it has not been clear to us how this happens, and many people have doubted it does. The problem lies in the way we perceive memory. Until recently we have imagined that our deep emotionally charged unconscious memories are fixed, just as these words are fixed on the paper, or as data are stored on the hard disk drive of our computers. But this is not so, the storage of memory is very different, and it's a good thing for us that it is.
John McCrone writing in New Scientist, 3 May 2003, reported on researches that have been done on memory. He wrote:
"Psychologists have long known that our memories are easily embellished. We add imaginary details through wishful thinking, or to make a more logical story. More controversially, memory may be falsified through suggestion and through manipulative questioning, bringing some eyewitness testimony and 'recovered' memories into doubt. And we all forget things too. But despite these flaws it was always presumed that the experiences themselves - the memory traces stamped into the fabric of our brain - were permanent. Look in the right place and we could always dig back to what really happened.
But that's simply not so, according to some surprising new research. A memory is anything but static. Resurrecting a memory trace appears to render it completely fluid, as pliable and unstable as the moment it was first formed, and in need of fixing once again into the brain's circuitry. Any meddling with this fixing process could alter the trace - or even erase it completely. Simply retelling a tale may be enough to change that memory for good. Long-term memory is effectively a myth."
McCrone went on to describe experiments done on rats by Karim Nader and Joseph Le Doux. They trained the animals to fear a box they were in by giving them mild electric shocks to the feet. After that the rats would become panicky if put back in the box, even if there was no electric shock - they remembered the unpleasant experience of the shock. The next thing they did was to give the rats an injection of a drug to stop protein synthesis, because the registering of memories is done by laying down of proteins in the nerve cells. Then when the rats were put near the box they again became panicky. But rats that had also been reminded of the experience by being shown the box immediately before the injection seemed to lose that memory, they were no longer frightened. They just wandered nonchalantly around the box. Now we know that people are not rats, but the nervous systems at the level of frightening memories are very similar between the two species.
It is well known that the memory of a recent event, in people as well as lower animals, is still quite 'fluid' before it is 'fixed' in the memory stores. For instance, if the brain experiences concussion, such as in an accident or a fall, the recent memories (but not the older memories) will disappear because they have not yet been 'fixed' in the memory stores. Nader and Le Doux concluded that, in the same way, when a memory is recalled it becomes 'fluid' again and is no longer fixed in the memory stores. In this case, the lack of ability to synthesize the proteins necessary to fix it in the memory stores led to its complete extinction. However, the implications are much wider than this. Maybe memories, when they are recalled and are 'fluid' again, can be altered in other ways. Maybe we can even turn nasty disturbing memories into 'warm fuzzy' ones. Experiments on humans support this idea.
Recalling memories renders them able to be altered; a lot of experimentation has been done to prove this. For example, McCrone wrote in the article:
"The idea that we enjoy a photographic record of the past is a myth that has also been exploded by experiments such as the 'eyewitness research' of Elizabeth Loftus of the University of California at Irvine. Here, subjects incorporated overheard details about a staged bank robbery or car crash in their own memories of the event (New Scientist, 23 July 1994, p 32). Loftus's work seems clear proof that our memories are fluid creations that can be edited or embroidered."
One of Loftus's experiments was to show people a movie of a traffic accident, then later ask them to recall it. Some of the people were asked, "How fast were the cars going when they hit each other?" The rest were asked, "How fast were the cars going when they smashed into each other?" The people to whom the emotive words 'smashed into' were used, even though they had all seen the same film, were much more likely to remember the cars going much faster and the accident being more destructive. Then a week later they were all asked, "Did you see any broken glass?" The people who had been asked the 'smashed' question were much more likely to remember seeing broken glass, although there was none in the movie. Loftus uses this research to emphasize that eyewitness testimony in legal cases may be unreliable, and even vulnerable to manipulation by examining attorneys, by the words they use. We see it also as an example of just how pliable memories are, once they have again come out of the memory stores.
Loftus' experiment demonstrated that the content of a memory can be changed. We are also interested in the emotional aspects of the memory, and here it becomes even more interesting, because emotional memories are even stored differently from neutral ones. Larry Cahill et al in 1994 (Nature, 371) reported experiments that found that emotional memories of an event involve adrenalin and nor-adrenalin which, in all of us, are increased by the emotional impact of the remembered event. Neutral experiences don't involve these hormones for remembering. The following year (Nature, 377) they used brain scanning techniques while the subjects were undergoing an emotional experience and saw that the amygdala, a structure in the mid-brain, was used in the remembering process. It was not used by those undergoing a neutral experience.
It is interesting to note that we remember the events surrounding an emotional or 'shock' experience better than a neutral one - maybe that's the function of the adrenalin, nor-adrenalin and amygdala. It's almost as if the brain says: "This situation may be important for my future survival, I must remember all about it." Most people can clearly remember where they were and what they were doing when they saw on TV or heard about the destruction of the World Trade Centre on September 11, 2001.
However, if the experience is too traumatic, especially in childhood, the memory is actively repressed and very difficult to remember unless some of the emotion is neutralized. This is why we can remember these experiences when we are in the tranquillity of the pratyahara stage of the meditation practices.
So why is yoga such a mind-purifying process? As we mentioned at the beginning, the memories of many of our past experiences - our samskaras - carry with them an unconscious emotional charge. They block our ability to evolve to our highest potential as well as determining our ongoing mental and mood states, and the way we interact with our world. If we are to grow, we must neutralize their power.
The majority of the physical techniques of yoga help to bring our deeply hidden memories with their emotions to the surface of the mind. Then the meditation practices give the memories a 'screen' onto which they are 'projected' so that we can become aware of them. It seems that what we are doing in the meditation then is to disempower the old samskaras by resurrecting the repressed memories when we are in the deeply relaxed state of the drashta - the witness or sakshi position. The resurrection of the memory then makes it 'pliable' and able to be changed by associating it with the disinterested relaxation rather than the old destructive emotion. It can then be re-remembered, but this time via the relaxed neutral route rather than the stressful adrenalin, nor-adrenalin, amygdala route. Then it ceases to have power over us forever.