It is helpful to understand some important aspects of the way that our brains work in order to appreciate important aspects of life and science.
Surveys reveal that people neither understand the nature and fallibility of perception, nor of memory and judgement. Most people think that vision works a bit like a video-camera and that memory is like playing back a recording. A modern understanding of perception and the brain demonstrates unequivocally that nothing could be further from the truth.
The failure to understand how perception and memory work has profound and serious implications. It affects the medical and legal professions in ways that can produce disastrous erroneous consequences (1).
For instance, there are undoubtedly many people, in North America especially, but also in other places, who have been jailed on the basis of recovered memories that misguided therapists have presented as evidence in court proceedings of mistreatment, usually of a sexual nature (the “false memory syndrome” (2)). Then there are the many prisoners on death row who have been sentenced to death largely, or solely, because of eye-witness testimony. Of those who have been exonerated prior to execution, because of the power of DNA-derived evidence, most were people who were originally convicted by eyewitness testimony.
In America, any of you could have been on death row, mainly because ignorant judges and ill-educated lawyers did not appreciate the fallibility of people’s senses. That is pretty drastic by any measure. It is still happening, the wheels of justice rotate gold-grindingly slowly. I would argue this is so because most of the legal profession are scientifically illiterate (being arts graduates): watch this TED video of Professor Loftus describing the case of Steve Titus who was accused of rape (posted Sept 2013).
The legal profession have failed to keep up with the evidence of the frightening fallibility of witness evidence. Most legal practitioners probably still think that a reliable witness will give a good account of something they have seen, like someone being assaulted in the street, or a theft from a shop, or a murder. However, scientific investigation demonstrates that is simply not true and that what you think you see/recall is not necessarily what actually happened. Any difficulty in accepting that proposition should be dispelled by considering what happens when you watch a magician do a trick.
“Your Honour, by your leave, I shall call 200 witnesses who were all present in the theatre and will swear on oath that he murdered the woman by sawing her in half in front of their very eyes”.
I have had a lifelong interest in magic tricks, and was taught how to do a few in my youth. I have always been interested in what magic can teach us about how the mind plays tricks on us. This is now a fertile area of study and recently some neuro-psychologists have teamed up with professional magicians (3-5) and, among other things, the neuro-psychologists learned more about how the brain works and the magicians learnt how to do some new tricks. Over the centuries magicians have developed sophisticated ways of fooling our senses, even if, till now, we and they did not always know exactly how they were achieving that.
So, when we consider the reliability and objectivity of what we think we see and remember, it pays to remind ourselves of how easily a magician can deceive us. This is a huge subject and here it is only possible to touch on certain specific aspects in order to develop some appreciation. For instance, the small central part (fovea) of your vision, which provides high-definition and colour, covers an area about the size of a coin held at arm's length (3 cm). The rest of your field of vision is closer to black-and-white and with much less definition of detail (the fovea is only 1% of the total retinal area, yet it has 50% of total number of neurones in the entire eye).
Yet, as you look around, you do not see a tiny area of colour surrounded by a grey blur, you are utterly convinced that you can see your whole visual panorama in detail and in colour: but your brain is deceiving you. Your brain is in fact reconstructing most of the scene the way it expects it to be, or the way it was last time you looked at it in detail. Also, your actual memory for those details, even if they have been recorded, is likely to be highly fallible. For a demonstration of this watch Professor Wiseman’s video
Thus, as soon as the magician has got you to look momentarily away from the key area where the trick is actually happening, and that only needs to be by a hand width or two, then he can do anything he likes outside of that narrow focus of attention/vision and you will almost certainly not be aware of it. A key magic skill is (mis)directing, especially misdirecting your (narrow) focus of attention.
Now let us consider how you subsequently recall the material that has been impressed upon your brain, however deceptively. Readers of an impressionable or delicate disposition may find the following information a little disconcerting. Put simply, what we think we remember is almost always wrong in many details, and quite frequently extremely deceptive. I mentioned above that most people think memory is like replaying a video: it is more like this; every time the video is played it is altered by the thoughts and emotions of that person and those interacting with them at the time, and each time it is subsequently re-played, that process is repeated. A simple illustration of this is the telling of an after-dinner story about some memorable past event. A partner/friend then contradicts the story-teller … “that didn't happen in Spain, that happened in Italy” etc. Indeed, once such stories have been repeated a few times people include recollections from the moods/scenes in which those stories were previously recounted, and after a few re-tellings some people may become convinced that, for example, they in fact participated in the original event, even though they were not even there. This sort of thing is not the exception, it is the rule.
Some years ago I remember filing a research paper that I had found and writing across the top “seminal”. In other words I thought it was ground-breaking. The paper recounted how some researchers in America found, in the basement of the University, some 25 year old taped interviews with adolescents who had been asked many questions about psychologically important events in their life. Things like their first sexual experience and a host of other deep and meaningful things that one might expect psychologists to delve into. It occurred to these researchers that it might be interesting to try to find these people and see what they now thought and remembered about those things. The sample was quite large, and they managed to find a high percentage of them and interview them again, some 25 years later. At the end of their paper they summed it all up by concluding that what the subjects now said about those key events and feelings had such a slight resemblance to what they had said at the time that the agreement between the two was no more than could be expected by chance. They concluded with a phrase that I have never forgotten which was along these lines; “what they now recall should not be regarded as veridical memories but more as existential reconstructions.”
Writing this required me to find and check the reference, which revealed that I did not even have the paper in my database: was this “memory” then itself an “existential reconstruction” of something I wanted to be true! Well, after some considerable effort I have re-found the reference, the authors are Offer et al. (6): and yes, the conclusion actually says, “… accurate memory of one's past is not better than chance in the mentally healthy individual, … . It would be more constructive to treat recollections as existential reconstructions.”
What a relief, I was pretty close, apart from the addition of “veridical”!
Ever since then, when I recall an event which my wife tells me is a mis-representation or exaggeration of what she herself recalls (which is of course always correct) my standard reply is “don't you interfere with my existential reconstructions”.
In part two I shall continue with some other aspects of this fascinating topic including the ground-breaking work of Professor Loftus (2, 7), and other things: meanwhile youtube, has valuable material
1.Wiseman, R, Paranormality: discovering the natural with the supernatural. New Scientist, 2011. 209(2803): p. 48-51.
2.Loftus, EF, Make-believe memories. Am. Psychol., 2003. 58(11): p. 867-73.
3.Macknik, SL, King, M, Randi, J, Robbins, A, et al., Attention and awareness in stage magic: turning tricks into research. Nat Rev Neurosci, 2008. 9(11): p. 871-9.
4.Martinez-Conde, S and Macknik, SL, Windows on the mind. Sci. Am., 2007. 297(2): p. 56-63.
5.Martinez-Conde, S and Macknik, SL, Magic and the brain. Sci. Am., 2008. 299(6): p. 72-9.
6.Offer, D, Kaiz, M, Howard, KI, and Bennett, ES, The altering of reported experiences. J. Am. Acad. Child Adolesc. Psychiatry, 2000. 39(6): p. 735-42.
7.Loftus, EF and Davis, D, Recovered memories. Annu Rev Clin Psychol, 2006. 2: p. 469-98.