part0012

What harm can it do? People ask skeptics this all the time about all kinds of beliefs. When you're talking about astrology or spoon-bending, maybe it's reasonable to claim that skeptics are just being purist intellectual snobs to carp. Many, maybe even most, paranormal beliefs are mostly harmless, other than creating a sort of background noise that Simon Hoggart has called 'interference with the truth'. But the consequences of some claims are too serious to take lightly. Most of these are in the medical field: even a treatment as simple as faith healing can cost lives if believers favour it over medical care. Just as serious in their impact on families and the social fabric are false memory syndrome and memories of child abuse 'recovered' under hypnosis .

John Diamond (1953-2001) was a well-known Sunday Times columnist and broadcaster married to writer and TV cook Nigella Lawson when, in 1997, be was diagnosed with throat cancer. He wrote frequently about his cancer and his experiences in treatment in his column and also in his 1998 book, C: Because Cowards Get Cancer, Too. As his situation worsened, readers' convictions that simple cures rejected by medicine could fix it poured ever faster into his mailbag. At his death he left behind a half-finished, scathing, and well-researched book on alternative medicine; it was published posthumously filled out with a smattering of columns and essays as Snake Oil and Other Preoccupations. In that book he wrote a simple summary of alternative medicine: 'It's not a question of alternative medicine not working, but of the classification not actually existing. There are interventions one can make which have some effect on illness and there are interventions one can make which have no effect at all. The former count as medicine, the latter don't.' Appeared in XVIII.3-4.

For three years now I've been writing about me and my tumour in the Times magazine each Saturday. As the cancer has degraded from easy-peasey treatable through the various surgeon-confusing stages to its current apparently terminal state, so the number of readers who have written in with alternative cures has increased. I've had the lot: Girson therapy, naturopathy, megavitamin diets, laetrile, Essiac - any and every therapy listed in the Questionable Cancer Therapies section of the Web's invaluable Quackwatch site has been offered to me as a cure.

None of them work, of course. I'm no particular fan of the free market in general, but if coffee enemas really did work the wonders that Dr Girson's followers claim for them then every cancer patient would be using them. And, of course, every cancer doctor would be prescribing them. The single belief shared by almost all my correspondents is that there's a conspiracy among all those egotistical, money-grubbing doctors to keep these cures away from the suffering public. The truth is, of course, that it's precisely because so many doctors are egotistical and money-grubbing that if any one of them found a way of curing currently incurable cancers they'd use it tomorrow, claim their position as saviour of mankind, and never mind what the drug companies –their partners in the conspiracy according to my correspondents – said

I don't deny that my correspondents have the best and kindest of intentions. They really do want me to be well. But what is remarkable is not that they believe in these cures but the extent to which they're willing to go to delude themselves in order to maintain that belief. What's equally remarkable is just how often the same phrases appear again and again in their letters .

This is always in the preamble to a story of a miracle recovery as in 'Two years ago my aunt's doctor said she had only three months to live ...' Except that doctors never quite say that. A year or so ago I was told that my cancer was probably incurable but that a particular form of chemotherapy might put it into remission. How long did I have? Well, the doctor said, it was hard to say. Possibly three months, possibly longer. If the chemo worked then possibly a year or two. Subsequently friends asked me the same question I'd asked the doctors: how long? For a while I told them what I'd been told: I had three months to live. But, of course, I hadn't been told that. It was a possible interpretation of what I'd heard, but then so was 'a year' or 'two years' or 'who knows?'

If I, so resolutely opposed to alternativism, found it easy to translate the prognosis so dramatically, how much more likely is somebody who has embarked on some last-ditch cure or another to make the same translation and thus prove the efficacy of whatever snake oil they're dosing themselves with?

Which always sounds impressive and invariably comes at the end of a story about somebody who'd been sent off home to die. The last time I got an email with this announcement in it I emailed back: if the patient had been sent home to die how come they were given the scan which showed that the tumour had shrunk? Scans are expensive and are generally given only to those the doctors think they can help.

It turned out, as it always does, that the patient had been using the treatment – Girson therapy in this case - alongside high-dose radiotherapy. She hadn't been sent home to die at all but had been told that if the radiotherapy didn't work then her time was limited. And indeed whenever I've bothered to check on one of these miracle cures which seems to have given remission or, rarely, a cure, it turns out that the patient has been taking it at the same time as some orthodox therapy. Why they should believe that it's the mad diet that works and that the radio- or chemotherapy has had no effect is beyond me.

In this country cancer doctors have to spend 50 percent of their time telling patients that they're going to check out earlier than they'd imagined. It must be a pretty depressing way to earn your living. No wonder, then, that when there's good news so many of them tend to hop and skip with pleasure. The chemotherapy I finished last year had a 33 percent chance of working and about a 25 percent chance, if it worked, of keeping me going longer than three months after it finished. When I started turning up at the various clinics some months after the three-month point, the doctors gambolled like beaming lambs. How marvellous this was! How remarkable! How clever I was! How clever they were! Quick: let's take some pictures for the academic press!

It was hard for me to remember in all of this that terminal still meant terminal. I can well imagine that if I'd been taking the snake-oil diet at the same time as the chemotherapy I'd have walked out of the clinic believing that something miraculous and rare had been achieved.

The remedy I most often hear this about is damned Essiac. Essiac is an ancient American Indian recipe which was touted by a now-dead Canadian nurse and is the pride of Canadian alternative medicine. Despite the fact that the Canadian Health Board has found it lacking in certain curative essentials –like curing, for instance – it seems to be a generally held belief that Essiac is some sort of 'official' cure in Canada. I put this to one Canadian doctor who said that yes: hospitals in Canada do offer it. But only in the same sort of way that hospitals in Britain offer a chapel to pray in.

This is usually given as evidence of the general petulance of the medical profession when faced with a miracle cure not of their causing. What it invariably means is that the patient is in remission – which is something entirely different from a cure. So often proponents of alternative medicine use the same arguments for their own beliefs that they use against those of the medical orthodoxy. Thus, for instance, a single paper which suggests that homoeopathy might possibly have some effect on some minor ailment or another is taken as proof that homoeopathy works in all eventualities while a single paper suggesting that some orthodox cancer therapy might not be all it's cracked up to be is taken by them as equal proof that no orthodox medicine is worth considering.

It's the same with remission and cure. Tell an alternativist that the cure rate for cancer using entirely orthodox methods has quintupled since the turn of the century and you might well hear that this is a scam perpetrated by the orthodoxy because when they say 'cured' what they really mean is 'hasn't returned for five years'. Which is true enough: generally speaking that is the definition. But then, as it was the definition all those decades ago it seems a pretty fair comparison to make. On the other hand, those same complainants are usually pretty happy to see a year or two years' remission effected, as they believe it, by some nonce remedy or another as evidence of a complete cure.

So do I tell my correspondents all of this? Usually no. And for the same reason their doctors don't tell them it either. Being in the situation they're in isn't much fun. After all, I'm in it too. And while there's part of me which thinks the honest thing would be to tell the truth, why should I make things worse than they already are? If they're happy believing what they believe then that's fine by me. When these particular chips are down, you take what succour you can get. And in any case I'm pretty certain that if I told them otherwise they wouldn't believe me.

John Diamond presented the point of view of a patient. Presenting the point of view of a doctor is Thurstan Brewin (1921-2001), an oncologist, Fellow of the Royal College of Physicians and Surgeons, and a former chair of Health Watch (www.healthwatch.org.uk). In this talk, presented at the fifth European Skeptics' Conference held in Keele in 1993, he explains the harm misplaced belief in alternative medicine can do and makes the case for 'opting out' of complementary therapies. Appeared in VIII.6.

Taken literally, alternative medicine covers only those therapies recommended instead of mainstream medicine – and complementary medicine only those recommended in addition to mainstream medicine. And this is how some people use the terms. Recently both meanings have been blurred, so that they are almost interchangeable, but with 'complementary' the preferred umbrella expression, though 'natural' and 'holistic' are by no means forgotten – until someone comes up with yet another name. Fringe is the most useful term because it covers everything that is not mainstream, without attempting to describe it in any other way. It was the term advocated in the book of that name by Brian Inglis, editor of The Spectator and a great admirer of fringe medicine, so nobody should object to it, but it seems that many now do.

Similarly, the neutral term 'mainstream' is a better name than 'conventional', 'orthodox', or 'scientific'. Orthodox is especially misleading as it suggests that some particular belief or system is followed. This is what is often claimed by critics, but it's not true and never has been. The fact is that mainstream medicine is more pragmatic than fringe medicine, less tied to beliefs and theories. In my view the best of it is also actually more, not less, holistic (not in the mystical sense, but in terms of treating the patient, not just the disease) for it aims to help both the patient's physical problems, taking full advantage of all that has been discovered this century, and at the same time every problem that the patient has, physical or psychological, with maximum encouragement, relaxation, and peace of mind. Moreover, mainstream medicine, since it is not tied to any system or belief, is free to incorporate any really effective remedy at any time, whether or not its mechanism is understood.

However, the medical establishment is now, it seems, so anxious not to be thought patronizing or arrogant that it is bending over backwards to be polite and show respect to almost any kind of fringe medicine. It is now in bad taste to speak of quackery, except perhaps in the grossest kind of deliberate fraud. The 1993 report of the British Medical Association (Complementary Medicine – New Approaches to Good Practice) is a good example of this, containing hardly a word of criticism of any branch of fringe medicine, however far-fetched. And hardly a hint of pride in the considerable achievements of mainstream medicine. This to me comes close to a betrayal of all those doctors and scientists today and in the past with just as much desire as anyone else to put the patient first, but with a keen honest intellect and little respect for woolly thinking and flim-flam.

It's much easier to prove that a procedure is bogus when it is used for diagnosis than when it is used for therapy. For example, looking at the eyes (iridology) or feet (reflexology) in order to tell what's wrong with other parts of the body – both methods are politely listed in the BMA report – can fairly easily be exposed as no better than palmistry or astrology. Some people are impressed when the answer turns out to be correct, but this is bound to be so quite frequently and the chance of its happening will further increase if age, or general appearance, or previous illness are taken into account. If the claims made for such tests are shown (perhaps by means of a little judicious deception, as used by the Consumers Association) to be worthless – adding nothing to the rate of successful diagnosis – then their advocates have no choice but to fall back on the old excuse used by some believers in the paranormal – that the mere testing of a remedy by skeptics can in some way inhibit the effect. At this point, further discussion or testing is unlikely to be rewarding.

Meanwhile, as with palmistry, astrology, and the paranormal, it is striking how many people want to believe it, need to believe it, get a thrill out of believing it – and will therefore exaggerate the accuracy of the diagnosis or prognosis given. It seems that part of human nature is in love with magic and that it is sometimes a relief to switch off our powers of reasoning and believe implicitly in such things, rather than just keep an open mind about unlikely possibilities.

As to treatment, one of the most remarkable things about the history of medicine is that until recently scarcely anyone saw that the best way to assess how much was being achieved was to compare results, Why was this basic common-sense approach not always obvious? However (as with 'league tables' purporting to measure the performance of schools, hospitals, and so on) if the groups being compared are not as alike as possible apart from the method of treatment, there is a big danger of coming to false conclusions. Hence – whenever nobody knows which of two treatment policies is best –there is a need to ask patients if they will agree to take part in a careful randomized comparison.

They lose nothing by doing so. On the contrary several studies suggest that they may gain something just from joining a trial. In fact, when doctors and nurses find themselves ill or injured, they should encourage this attitude by asking to be included in such comparisons. This is a very different matter to research aimed at new discoveries; or at a better understanding of mechanisms. It is simply comparing outcomes. It is answering a very practical question: which policy gets the best results?

In Health Watch, we don't see how any reasonable person can argue against this in principle, no matter what the type of remedy, no matter what the theory behind it, and no matter to what extent treatment is individualized. Once you have two groups that are broadly the same apart from how they are treated, you can make any comparison between two policies that you like. All the advantages and all the disadvantages – physical and psychological, short term and long term – can be compared. Anything that anyone wants to compare can be compared. For example, alongside more objective aspects, there is no reason why the percentage of patients who merely feel happier than they did before the treatment cannot be compared. Whichever way you look at it, valid comparison is the key.

Is this approach really, as some critics claim, no more than just the current thinking of Western medicine and Western science? On the contrary, is it not rock-hard, inescapable logic? And is it not the honest, common-sense way to get at the truth? And is it not surprising that for many centuries reasonable human beings worldwide have not urged that it should be done? If 'amazing' results occur after a particular form of treatment, how often do similar results occur (a ) after this treatment, (b ) after other treatments, (c ) after neither? If there is a difference, we want to know which policy gives the patient the best chance of doing well.

To take one very small current example, how many of the thousands of women who take evening primrose oil for pre-menstrual tension are aware that a Swedish double-blind trial has found that this very popular 'alternative' remedy (with a name like that, how could it fail?) had no more effect than ordinary liquid paraffin? Perhaps customers should have a right to this sort of evidence before they decide how to spend their money.

The history of medicine shows all too clearly how easy it is for both doctors and patients to be convinced that a remedy is beneficial when, in fact, it is doing no good – or even doing harm. It has happened many times in mainstream medicine as well as in fringe medicine. There is no 'remedy', however worthless, that does not have its quota of grateful patients. This is due partly, but not entirely, to the placebo effect. In Health Watch (which has an updated position paper on this subject, if anyone is interested), we fully recognize the powerful and vital subjective help that one or more kinds of placebo therapy can give, together with listening, understanding, encouragement, relaxation, and so on. However, though many people long to believe that equally powerful objective effects can occur – including measurable physical healing and cures that would not otherwise have occurred – the evidence for this, though important and interesting, is only slight.

It is often forgotten that there are at least three other explanations, quite apart from the placebo effect, for patients feeling convinced that a treatment has helped them. First, many medical conditions are self-limiting. Those people who always take a remedy of some kind – or always want their doctor to give them one, even if he or she doesn't think it is necessary – fail to appreciate this, because they have so little experience of it. Many, though they talk a lot of natural healing and self-healing, seem surprisingly reluctant to take no remedy in situations where this is appropriate. Ironically they often seem to have less confidence in this policy than do many in mainstream medicine.

Second, in many long-standing conditions spontaneous improvements and remissions – lasting weeks, months, or even years – are common. In fact, nobody is more keenly aware of the self-healing powers of the human body than the men and women who practise mainstream medicine. Third, belief that a remedy has been successful is often based on a false assumption – the assumption that without it there would have been no improvement, or steady deterioration, or perhaps even death. People love to say that they know they would now be dead if it wasn't for some fringe medicine remedy. But this may not be true at all: the same thing happens to patients who have had nothing but standard treatment.

Following the completion of mainstream medicine for a cancer, for example, all trace of the disease may be gone and the patient may now feel completely well (perhaps cured, but with no guarantee of this). Then fringe medicine of some kind is added – and if the patient does exceptionally well, that's great, but no prizes for guessing which treatment then tends to get the credit. 'Living longer than expected' is by itself worthless as evidence, unless it can be shown to happen more often after this extra treatment than without it. It is quite common in mainstream medicine for patients to do not just better than average but far better than average. It happens all the time.

Another reason for misplaced gratitude is when completely healthy people (in so far as any of us are ever completely healthy – it would be very surprising if we were, given the amazing complexity of the ingenious mechanisms that keep our bodies ticking over) are conned into thinking that if they want to stay well they had better have a fringe remedy of some kind. Many people do this for years, the total cost mounting up to large sums, which they can ill afford. Those who stay well would probably have stayed well anyway .

All doctors have been patients at certain times in their life. Though they don't often talk about it ('it's funny to think of the doctor being ill' is still sometimes heard in wards or clinics) some have had more experience of being ill or in pain than have many of their patients. Here are two very ordinary, commonplace experiences of my own that illustrate two of the points I've made.

The first time was when I was recovering from major medical surgery and had a day when I felt very ill, but no cause was evident, so I got nothing for it. No suggested explanation, no reassurance, no hopeful suggestion that I would probably feel better next day, no humour, no mock chiding for feeling sorry for myself (too much sympathy is as bad as too little), and no placebo. A brief word of encouragement, combined with a spoonful of pink peppermint water –something equally cheap and harmless – would have cheered me up. This is an example of modern hospital staff sometimes failing to live up to the traditions of simple old-fashioned common-sense mainstream medicine.

The second time was when after months of severe sciatic nerve root pain (possibly made a little easier by the soothing and comforting hands of a sympathetic masseuse, but that's all – no real change) I was given a very gloomy prognosis by a senior neurosurgeon. However, without any remedy of any kind, it then all cleared up and I had no trouble whatever for the next fifteen years. The point here is that had I visited, say, an osteopath or chiropractor or acupuncturist, what happened would have been regarded by many people as impressive evidence for the effectiveness of alternative medicine.

To return to the 1993 BMA report, many of the dozens and dozens of different types of fringe medicine are based on some all-embracing theory regarding the way in which one part of the body is supposed to influence all other parts; or on some vague idea of imbalance and loss of harmony; or on the need to cleanse the body, or on the importance of unblocking channels of energy. In the past these sorts of theories were popular in mainstream medicine. But as soon as science and reason and hard work solve a problem and the real cause is discovered (of malaria, for example, which used to be thought due to 'bad air', hence its name) is such guesses are no longer needed.

Most fringe theories contradict each other, but the BMA is too polite to point this out in their report, contenting themselves with urging a register of all groups, so that after training they become 'competent' and have the necessary 'good practice'. Not wanting to offend anyone or sound patronizing, they make little or no attempt in this report to demarcate the absurd or the undesirable. Isn't it rather probable that the competent and skilled 'good practice' of nonsense, following a course of thorough training in nonsense, will remain nonsense ?

Some branches of fringe medicine are now behaving in a much more honest and realistic way. Most osteopaths and chiropractors, for example, seem now to have quietly given up the claim that they stuck firmly to for more than a hundred years – that spinal manipulation was capable of curing or alleviating almost any disease in any part of the body. Since half the population suffers from intermittent backache, just sticking to that problem alone can no doubt keep them busy and earn them many grateful patients. Most are also very well trained in anatomy and much else from mainstream medicine, though obviously without as much practical experience of both diagnosed and not-yet diagnosed patients, as they would have if they had been through medical school.

An increasing number of fringe practitioners also now support proper randomized trials. But no single clinical trial can provide complete confirmation (or complete negation) of any theory or belief, and it seems likely that some hold so strongly to their convictions that they will believe only those trials that seem to confirm them. Only a small minority seem to have a reasonably open mind.

So does yet another wave of enthusiasm for fringe medicine (there have been many previous ones in history) do any real harm? Mainstream medicine has always believed in curing sometimes, relieving often, and 'comforting always'. This basic, traditional teaching cannot be denied merely because some doctors fail to live up to it. And fringe medicine, even if it is 95 percent placebo therapy (compared with mainstream medicine's equivalent figure of perhaps 60 percent in the early part of this century and perhaps 30 percent now), can at least help with the comforting. So why not let people spend their money this way if they wish? Well, here are a few points that at least should make us pause before we do anything that encourages still further the recent huge expansion of fringe medicine:

The nature of memory is art eternally interesting topic. Speculation about bow memory works took a dangerous turn in the 1990s, however, when the notion that the trauma of child abuse might cause victims to forget the abuse entirely until a therapist helped them 'recover' those memories, usually under hypnosis, gained ground. The problem thus created has a name: false memory syndrome. In tins talk, given at the Remembering Trauma Conference held in London in September 2003, independent scholar Mark Pendergrast (www.nasw.org/users/inarkp), author of Victims of Memory, an investigation of false memory syndrome, describes how people can develop false memories of terrible events. Appeared in XVII. 4.

People can come to believe in extremely traumatic events that never happened. It is quite clear that this does happen in the case of alien abductees or in the cases of medically verified virgins who remember being raped during their childhood. It is also quite clear to me from my research that this has happened in thousands, if not millions, of cases in North America and the UK, but I cannot prove that assertion. Still, some cases of illusory memories are provable. What follows is an explanation of how this is possible.

First, to get someone to remember something horrible that never happened to them in their childhood, they have to be very motivated. There is a common misconception that therapists can 'implant' memories. I do not like the word implant at all. In order to believe in repressed memories, you have to be very motivated, and your motivation usually involves a quest to solve the puzzle of your life. We all want to have explanations for what has happened to us, and we all tend to seek fairly simple explanations, so it is very appealing to say, 'Well, I have trouble with relationships, I have an eating disorder, I have trouble with my self-esteem, and these are symptoms of sexual abuse, so maybe I was abused and repressed the memory.' During the height of the recovered memory movement, in the late 1980s and early 1990s, this was a common belief system, and many still believe it. So, many people –particularly women seeking therapy – were highly motivated to come up with a solution to their life problems.

Secondly, there was secondary gain involved in almost every case I investigated. What I mean by that is that people, by being victims of sexual abuse, got a lot of attention they would not ordinarily have had. They got a lot of sympathy and, not to be harsh about it, they also could avoid a lot of responsibility for things in their lives at various points. This is not to say that this kind of belief system did not also cause extreme suffering, but there is no question that there was secondary gain.

The third point is, you have to have a belief in the theory of massive repression or massive dissociation, and many people did, and many people still do. When I was living in England for two months in the spring of 2003, I did an informal survey of people as I was travelling on trains, or when I was in pubs, or when I was walking up and down the barge canal. I asked people, 'If you were eight years old and you had a terrible, terrible thing happen to you, do you think that you could block that completely out, not have any memory of it, and then remember it later in life?' The vast majority of people said, 'Oh yes, you can do that, that happens.' I then asked, 'Well, how do you know?', and they would answer, 'Well, I just know,' or 'I've seen it on television or in a movie'. So – you have to have a belief that massive repression is something that people can do.

It also helps, although it is not necessary, to have an authority figure you go to who says, 'Oh yes, that's true. I know this is true because I have a PhD [or I'm a psychiatrist or I'm a social worker], and I've seen many people come through my office who had exactly the same symptoms that you do – these troubled relationships, problems with self-esteem and eating disorders – and many of them had these memories come back, that they had not remembered for many years, of being sexually abused, and so I think you may have repressed memories, too.' It really is an encouragement to illusory memories, but I'd like to emphasize that it is not necessary. You don't need an authority figure –illusory memories can be totally self-induced and, in many cases, they are.

A great deal has been said or written about the hazards of hypnosis , but I do want to add other things, and this is primarily what you will find in the chapter on 'How to Believe the Unbelievable' in my book Victims of Memory (1996). In this chapter, I went through tick, tick, tick; these are the ways that you can come to believe things that did not happen. Certainly hypnosis (or guided imagery, visualization, meditation, or prayer, which are all forms of hypnosis or auto-hypnosis if used to try to recall 'repressed' memories) is a very good way to do that, particularly if the authority figure who is leading you in the form of hypnosis has a vested interest in this theory of massive repression and believes that you may very well have been abused. I also want to warn about something called 'inadvertent cueing'. Many therapists are told, 'Don't use leading questions with people, don't lead your clients'. I do not think that anybody does intentionally lead their clients, but I interviewed many, many therapists who believed in repressed memories, and they all did lead their clients. They told me in the next sentence, after they had told me exactly how they had led their clients – 'but you must be very careful never to lead your clients. I always maintain a totally neutral stance', and so on.

If you believe in this idea that you can forget years of horrible things and then remember them much later, you are likely to convey that belief to your clients. And so I have told therapists – 'Be careful what you believe!' I think that ultimately this whole thing comes down to something I again want to emphasize, a belief system. It does not really matter what modalities you use. As Harvard Professor of Psychology Richard McNally found in his studies, many people have a very firm belief that they are incest survivors without having any actual memory of anything happening to them. They simply believe it, and once you believe it, I think that it is almost a foregone conclusion that you will come up with something.

For instance, recovered memory therapists use dream analysis. Frequently we dream about things that we are worried about, and if you are in therapy and you think that maybe your father sexually abused you, or that someone else did, you begin to obsess over it, and that is precisely what you will dream about. Consequently, many of these things become self-fulfilling prophecies. The same thing is true of so-called body memories where they tell you that you may have some panic attack or you may have some bodily symptom and then you sort of work yourself up into it, or pay particular attention to it.

Once you come up with a scenario – and I saw this over and over again in this type of misguided therapy – you come up with a fragmentary image. What would happen would be that the therapists would take these fragmentary images and then they would have people rehearse them over and over again. In fact, they would tell them, 'Pretend that you have a movie screen or a television screen in your head and you have to visualize it, and you have to zoom in and freeze frame.' They would literally tell people to do those things – it was all very visual. So people would develop a script, a narrative, and they would have them write the narrative down over and over again, or repeat it in group sessions over and over again. The more you repeat something and the more you rehearse it, the more it becomes true for you. Many retractors who took back their memory beliefs because they decided that they were incorrect still cannot get rid of the intrusive images. They have post-traumatic stress disorder. That would be an interesting thing to study –these people who have gone through this kind of therapy and developed a false belief system, then disbelieved it, but still cannot get rid of the intrusive memories of something they know rationally did not happen to them, such as, say, being in a Satanic cult.

This is a theory that was put forward by Leon Festinger quite a few years ago. It is quite an interesting theory and I think it makes sense, but it is just a theory. The idea is that you cannot have two contradictory ideas in your head at the same time. One of them is going to push the other one out like a cuckoo pushing an egg out from the nest. So if you opt for the idea that daddy did this horrible thing to you, you cannot very well have the idea that daddy was also a loving parent who did all these nice things with you, even though you have these very valid memories that he was a nice guy in many ways. So once you plump down on the side of this new belief system it is almost like a seesaw that goes 'whomp', and to 'unwhomp' it is very, very difficult to do. Once somebody opts for a belief system, and invests in it, and goes public with it, it is extremely difficult to undo.

Many, many times, people have said to me, 'Why would anybody make up something so dreadful? Why would anybody want to make up something so horrible about someone as central in their lives as their parents?' But it is not a matter of wanting – it is a matter of having a seed planted in your mind and having it grow almost inevitably. So it is really a belief system, followed by methods that really are quite suggestive to your memory. Memories are always reconstructive, and they can be changed – sometimes permanently. So I can only hope that you can remember some of what I have said here at least fairly accurately .

"How far can you trust human memory? This question matters greatly when trying to assess a paranormal claim, because most of the time you are trying to assess someone's report of a personal experience rather than witnessing the event directly yourself. The person recounting the incident may be honest, sincere – and yet still make errors of perception or interpretation. In the case of the Knock apparitions, for example, the description of the figures the villagers saw as two-dimensional and unmoving did not stop some from concluding that they had seen the Blessed Virgin Mary with St Joseph and St John the Evangelist. Two related strands of psychological research are relevant to this issue. First, as discussed by Mark Pendergrast in the previous chapter, is the phenomenon of 'memories' that have no basis in fact. Second, with a much longer history within psychology, is the question of the accuracy of eyewitness accounts which over time may become so distorted as to be completely unreliable. Professor Chris French, head of the Anomalistic Psychology Research Unit at Goldsmiths College, University of London, and co-editor of The Skeptic (2001-present), explores the workings of human memory. Appeared in XVII.1."

Textbooks often begin their discussion of memory with the rather obvious observation that memory does not work like a video camera. At first glance, it might strike you that it would be better if it did. Imagine if you could just press the right mental button and be treated to an exact mental replay of events you had witnessed in the past – wouldn't that be fantastic? Well, yes and no. One can think of several situations where it would be advantageous –settling arguments between husbands and wives, for example. But I only have to think about the disorganized state of our video collection at home to realize some obvious problems. How on earth would you ever find the memory that you wanted?

But the problem isn't just one of locating the right bit of mental footage. Unlike, material recorded on videotape, memories can and do change over time. A memory is more like a dynamic mosaic than a series of static unchanging frames recorded by a video camera. The very first time that you try to recall an event, you will engage in a constructive process – you will literally build that memory from different bits and pieces. Some of those bits and pieces will correspond to more or less accurate memory traces laid down at the time you witnessed the event, but even then you may not put them together properly. Furthermore, the mosaic you build will be influenced by things that happened to you before the event in question that led you to have particular expectations and a particular way of viewing the world. It will also be influenced by your current view of the world and of yourself. There will also be a general tendency to fill in any gaps in such a way that the whole 'makes sense' .

In general, we do not remember the surface details of events at all well; we remember the gist. We automatically extract the important essence of events and forget the superficial and transitory packaging. This is both the great strength and the great weakness of the way our memories work. It is a strength because we don't process and store all of the minutiae of life. We pay attention to the important stuff and forget the rest. Why lay down in memory a complete verbatim record of every conversation you ever had or every song you've ever heard? But it is a weakness because sometimes we do need that level of detail and it will probably elude us. Or, worse still, we may confidently believe that a memory we hold is a true reflection of an event when in fact it may be distorted beyond recognition.

There are only a few areas where the accuracy of our memories is so important that we make any attempt to assess it. Examples include forensic psychology – it appears that we are probably far more impressed by eyewitness testimony to crimes than we should be. Another area where it becomes important is anomalistic psychology, the psychology of unusual experiences and beliefs. Just how accurate are eyewitness reports of UFOs, ghosts, and the Loch Ness monster? Or even alien abductions? And of course there's always the settling of marital arguments.

Most of the research on eyewitness testimony has been driven by the need to understand factors affecting the reliability of reports from witnesses to crimes. It is now generally accepted that such reports can often be wildly inaccurate, leading to gross miscarriages of justice. The circumstances surrounding crimes are often precisely those that will lead to poor recall. The event is unexpected, often over in seconds, and sometimes extremely frightening. Or it may be that the police need details of events that preceded a crime – events which no one at the time realized would be that important. One obvious reason that we may fail to remember things accurately is simply that we failed to pay attention to the right details at the time. Typically, we pay attention to the information that is relevant to our goals at the time – and it can sometimes be amazing what we miss!

I can illustrate this with a true story of a visit to an estate agent that I made with my wife when we were looking to move house many years ago. As we left the estate agents, having looked at details of various houses, I said to my wife, who is also a psychologist, 'That was very strange. It reminded me of a psychology experiment.' She was rather confused by this and asked me what I meant. I said 'You mean you didn't see it?' 'See what?' she said. I told her to look through the estate agents' window to see if she could see anything a little bit unusual. She did – and could not believe that she had failed to spot a full-size stuffed bison that for some unknown reason was on display in the office! This nicely illustrates the fact that people may vary in terms of what information they encode at any particular moment. My wife was very focused on house buying – what price, where, how many bedrooms – my mind was perhaps not so fully focused on the important task in hand.

Research into what is known as 'change blindness' provides another illustration of our inattention to aspects of our surroundings. In a typical study, people queuing at a library issue desk are handed a form to fill in by the librarian. At one point in the interaction, the librarian disappears from view, as though retrieving a dropped piece of paper, but another completely different person emerges in their place. Around half of the participants simply do not notice the change.

A huge amount of experimental evidence, in addition to our everyday experience, shows us that our memories are poor if we haven't paid attention in the first place. No big surprise there. But what about those situations where it's really important that we pay attention and get things right? Even here, our memory can play cruel tricks. Donald Thomson, a psychologist in Australia, was arrested by the police and forced to take part in a line-up. He assumed he was being harassed in response to his strong views on the unreliability of such line-ups. Things got very serious, however, when he was identified by a very distraught woman and told that he was being charged with rape. It transpired that the rape had taken place with the television on in the room at the time of the attack. The programme being shown was a live debate on the reliability of identity parades, featuring both Thomson and the Assistant Commissioner of Police. The victim had unintentionally based her description of the rapist on Thomson, who was on television at the time. Fortunately, he had a large number of viewers to provide him with a watertight alibi.

There are, of course, those vivid memories that we just know are right. One example is so-called flashbulb memories. We can all remember with perfect accuracy where we were, what we were doing, who we were with, when we heard about the attack of September 11 – can't we? There seems to be something about such moments that burns the details into our very brain cells. I can still remember, for example, hearing the news of John F. Kennedy's assassination. I was only 7 years old at the time, so when I heard the newsflash on TV, it didn't mean that much to me. But I remember ambling into the kitchen to tell my mum and dad about it anyway. It was from their reaction that I realized that this was news of stupendous importance. I used this example of a flashbulb memory in my lectures for years in my adult life and on one occasion happened to mention this to my mother. She told me that it just didn't happen that way at all. We were not at home and it was not me that broke the news. Interestingly, I had been the victim of a false memory that put me right at the heart of the action! Again, experimental evidence has shown that flashbulb memories – often held with great conviction – are often just plain wrong. American students recorded details of how they heard the news of the Challenger disaster the morning after it happened – who they were with, what they were doing, and so on. A couple of years later, many of them had completely different recollections of that event.

It appears that when we try to recall something, the mosaic memory we bring to consciousness consists of memory traces of the original event plus other memory traces, perhaps relating to other similar events or even to daydreams or fantasies. Gaps in memory will sometimes be effortlessly and automatically filled in to produce our recollection – and we will often have no way of knowing which bits we can trust and which we cannot. Sometimes we may be fooled into thinking that something really happened when in fact we only imagined or even dreamt it. Our ability to distinguish between memories for events that really happened and those memories that are internally generated is known as reality monitoring. An everyday example is trying to decide whether you really did lock the backdoor or just thought about it. At the other extreme is psychotic breakdown in which the sufferer is totally unable to distinguish between mental events and events out there in the real world.

Although psychologists have long recognized that firsthand accounts of witnessed events were unreliable, it is only within the last decade or so that research has been directed at the possibility that people may sometimes have rich and detailed memories for events that they have never actually witnessed at all. The main reason for this explosion of research into false memories was the sudden increase in cases of alleged recovered memories of childhood sexual abuse, especially in the USA. Typically in such cases, adults would enter psychotherapy suffering from a variety of common psychological problems such as depression, low self-esteem, or insomnia. As part of their psychotherapy they would engage in mental exercises such as hypnotic regression and guided visualization, intended to unlock any repressed memories of traumatic childhood events thought to be causing their problems. Many thousands of people who had entered therapy with no conscious memories of being abused as children became convinced that their now-aged parents had indeed inflicted terrible suffering upon them decades earlier. In some cases, these allegations included claims of Satanic ritualized abuse, involving human sacrifice, cannibalism, sexual torture, and forced abortions. Many of these cases went to court and led to convictions even though the cases rested entirely upon verbal testimony. Families were torn apart in the most brutal way imaginable.

Experimental psychologists tended to doubt the accuracy of the memories recovered via hypnosis and related techniques. A huge amount of experimental evidence shows quite convincingly that hypnotic regression does not provide a magic key to unlock the unconscious mind, forcing it to reveal its hidden memories. Instead, the hypnotic regression procedure is such that it provides a context in which individuals often produce an account mixing fantasy with pre-existing knowledge and expectations – and then believe with total conviction that the account reflects events that really took place. Indeed, experimental psychologists have expressed doubts about the very concept of repression itself. The idea that the unconscious mind can somehow automatically take over and hide away memories for traumatic events is not supported by any convincing experimental evidence, although there are many accounts of what appears to be repression occurring outside the laboratory.

In the early days of the controversy, those who believed that recovered memories were largely accurate would sometimes object that, although memory for peripheral details of a witnessed event might be distorted, there was little evidence that people were prone to false memories for episodes that had never actually occurred at all. Things have moved on since then, thanks to the pioneering work of Elizabeth Loftus, amongst others. We now know that it is alarmingly easy to plant false memories in a sizeable minority of the population using well-established experimental techniques. It has been shown, for example, that hypnotic regression is not the only way to induce false memories. Simply getting people to imagine events that did not actually take place is often sufficient to lead people to believe that they did witness or take part in the events in question.

The difficulties of deciding whether a memory reflects a real event or not is illustrated by something that happened to Elizabeth Loft us herself. Loftus's mother had died by committing suicide. She had drowned herself in a swimming pool, but Loftus had never actually seen her mother's body – or so she thought. Many years later, and long after Loftus had established her reputation as the leading psychologist in false memory research and one of the main critics of the concept of repression, she was attending a family get-together when one of her uncles insisted that she had in fact seen her mother's body. He said that Loftus was the person who had found the body floating face down in the pool. An image of her mother's lifeless body immediately filled Loftus's mind. She was flabbergasted – for years, she had questioned the notion that the mind just locks away memories that are too ghastly to face. But it appeared she had done just that. Over the next few days, her memory of that terrible sequence of events become clearer and more detailed as she dwelt upon this horrible revelation. And then she called her brother to tell him – and he said the uncle was wrong, Loftus had not found the body! This was confirmed by other family members. Far from experiencing a recovered memory, Loftus had, in fact, been the victim of a false memory.