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Why psi tells us nothing about Consciousness

Presented at Tucson II, 13 April 1996
In the plenary session "Current directions in parapsychology"

Also published in 1998 in S.R.Hameroff, A.W.Kaszniak and .C.Scott (Eds) Toward a Science of Consciousness II. MIT Press. 701-707.
Note that there were problems with the editing of this volume and there are some misprints. This version is correct.

I wish to ask two questions about the relationship between consciousness and psi.

1. Are there any paranormal phenomena? and

2. If there are, do they help us to understand consciousness?

For the first I would like to be able to provide a fair and unbiased assessment of the evidence for psi, however briefly. This is simply impossible. Many people have tried and failed. In some of the best debates in parapsychology the proponents and critics have ended up simply agreeing to differ - for the evidence can be read either way (e.g. Hyman and Honorton, 1986). The only truly scientific position seems to be to remain on the fence, and yet to do science in practice you have to decide which avenues are worth pursuing. I do not think psi is.

My reasons are not an objective evaluation of the evidence but more than twenty years of working in, and observing, the field of parapsychology. During that time various experimental paradigms have been claimed as providing a repeatable demonstration of psi and several have been shown to be false. For example, it took more than thirty years to show that Soal had cheated in his famous experiments with the special subject Basil Shackleton (Markwick, 1978). The promising animal precognition experiments were blighted by the discovery of fraud (Rhine, 1974) and the early remote viewing experiments were found to be susceptible to subtle cues which could have produced the positive results (Marks and Kammann, 1980).

The most successful paradigm during that time, and the one I shall concentrate on, has undoubtedly been the ganzfeld. Subjects in a ganzfeld experiment lie comfortably, listening to white noise or sea-shore sounds through headphones, and wear half ping-pong balls over their eyes seeing nothing but a uniform white or pink field (the ganzfeld). Meanwhile a sender in a distant room views a picture or video clip. After half an hour or so the subject is shown four such pictures or videos and is asked to choose which was the target. It is claimed that they can do this far better than would expected by chance.

The first ganzfeld experiment was published in 1974 (Honorton and Harper, 1974). Other researchers tried to replicate the findings and there followed many years of argument and of improving techniques, including the "Great Ganzfeld Debate" between Honorton (1985) (one of the originators of the method) and Hyman (1985) (a well-known critic). By this time several other researchers claimed positive results, often with quite large effect sizes. Both Hyman and Honorton carried out meta-analyses combining the results of all the available experiments but they came to opposite conclusions. While Hyman argued that the results could all be due to methodological errors and multiple analyses, Honorton claimed that the effect size did not depend on the number of flaws in the experiments and that the results were consistent, did not depend on any one experimenter, and revealed certain regular features of ESP.

The ganzfeld reached scientific respectability in 1994 when Bem and Honorton published a report in the prestigious journal, Psychological Bulletin. They reviewed Honorton’s earlier meta-analysis and reported impressive new results with a fully automated ganzfeld procedure, claiming finally to have demonstrated a repeatable experiment. So had they?

My own conclusion is biased by my personal experience. I tried my first ganzfeld experiment in 1978, when the procedure was new. Failing to get results myself I went to visit the laboratory in Cambridge where some of the best results were being obtained. What I found there had a profound effect on my confidence in the whole field and in published claims of successful experiments.

These experiments, which looked so beautifully designed in print, were in fact open to fraud or error in several ways, and indeed I detected several errors and failures to follow the protocol while I was there. I concluded that the published papers gave an unfair impression of the experiments and that the results could not be relied upon as evidence for psi. Eventually the experimenters and I all published our different views of the affair (Blackmore, 1987; Harley and Matthews, 1987; Sargent, 1987), and the main experimenter left the field altogether. I turned to other experiments.

I would not be bringing up this depressing incident again but for one fact. The Cambridge data are all there in the Bem and Honorton review. Indeed, out of 28 studies included, 9 came from the Cambridge lab, more than any other single laboratory, and they had the second highest effect size after Honorton’s own studies. Bem and Honorton point out that one of the laboratories contributed nine of the studies but they do not say which one. Not a word of doubt is expressed, no references are given, and no casual reader could guess there was such controversy over a third of the studies in the database.

Of course the new auto-ganzfeld results appear even better. Perhaps errors from the past do not matter if there really is a repeatable experiment. The problem is that my personal experience conflicts with the successes I read about in the literature and I cannot ignore either side. I cannot ignore other people’s work because science is a collective enterprise and publication the main way of sharing our findings. On the other hand I cannot ignore my own findings - there would be no point in doing science at all if I did. The only honest reaction is to say "I don’t know".

Since then the CIA have released details of more than twenty years of research into remote viewing (Hyman, 1995; Utts, 1995), and the spotlight has left the ganzfeld. Perhaps the ganzfeld will go down in history as evidence for psi - but I am left with my personal doubts about this, as about other paranormal claims. I have had many experiences of hearing about a new finding, spending a lot of time and effort investigating it, and ending up disappointed - whether it be an experiment, a haunting, an incredible coincidence or a new psychic claimant. Of course that is no proof that psi is not there. I might really be a "psi-inhibitory experimenter" and so be unable to observe the psi that is there, or I might just have been looking in the wrong places.

This is why I cannot give a definitive and unbiased answer to my question "Are there any paranormal phenomena?" I can only give a personal and biased answer - that is, probably not.

But what if I am wrong and psi does really exist? What would this tell us about consciousness?

The popular view seems to be something like this - if ESP exists it proves that mental phenomena are non-local, or independent of space and time - and that information can get "directly into consciousness" without all that nasty messing about with sensory transduction and perceptual processing. If PK (psycho-kinesis) exists it proves that mind can reach out beyond the brain to affect things at a distance - that consciousness has a power of its own.

I suspect that it is a desire for this "power of consciousness" that fuels much enthusiasm for the paranormal. Parapsychologists have often been accused of wanting to prove the existence of the soul, and convincingly denied it (Alcock, 1987). I will instead accuse them of wanting to prove the power of consciousness. In Dennett’s terms you might say they are looking for skyhooks rather than cranes. They want to find that consciousness can do things all by itself, without dependence on that complicated and highly evolved brain.

I have two reasons for doubting that they will succeed. First, parapsychologists have yet to demonstrate that psi has anything to do with consciousness, and second, there are theoretical reasons why I believe the attempt is doomed. But note that by consciousness I am referring to the really interesting aspects of consciousness, that is subjectivity, or the "what it is like" to be something.

First, to make their case that psi effects actually involve consciousness, experiments rather different from those commonly done will be needed. Let’s consider the ganzfeld. Do the results show that consciousness, in the sense of subjectivity or subjective experience, is involved in any way?

I would say no. There are several ways in which consciousness might, arguably, be involved in the ganzfeld, but there appears to be no direct evidence that it is. For example, even in a very successful experiment the hits are mixed with many misses and the subjects themselves cannot say which is which (if they could the successful trials could be separated out and even better results obtained). In other words, the subject is unaware of the ESP even when it is occurring.

The ganzfeld does involve a kind of mild altered state of consciousness. Indeed Honorton first used the technique as a way of deliberately inducing a "psi conducive state". However, it has never been shown that this is a necessary concomitant of ESP in the ganzfeld. Experiments to do this might, for example, compare the scores of subjects who reported entering a deep altered state with those who did not. Or they might vary the ganzfeld conditions to be more or less effective at inducing altered states and compare the results. These kinds of experiments have not been done. In the absence of appropriate control conditions we have no idea what it is about the ganzfeld that is the source of its success. It might be consciousness, it might be the time spent in the session, the personality of the experimenter, the colour of the light shining on the subject’s eyes, or any of a huge number of untested variables. There is simply no evidence that consciousness is involved in any way.

Another example is recent experiments on remote staring (Braud and Schlitz, 1989). It has long been claimed that people can tell when someone else is looking at them, even from behind their head. Ingenious experiments now use video cameras and isolated subjects to test this claim. Results suggest that the staring and non-staring periods can be distinguished by physiological responses in the person being stared at. In other words, they are able to detect the staring - but not consciously. These experiments may be evidence that something paranormal is going on but whatever it is it appears to be unconscious rather than conscious.

In PK experiments the claim that consciousness is involved is made explicitly. For example, a well-known paper is entitled "The effects of consciousness on physical systems" (Radin and Nelson, 1989). Yet, as far as I can see, there is no justification for this title.

In these experiments a subject typically sits in front of a computer screen and tries to influence the output of some kind of random number generator (RNG), whose output is reflected in the display. Alternatively they might listen to randomly generated tones with the intention of making more of the tones high, or low, as requested, or they might try to affect the fall of randomly scattered balls or various other systems. The direction of aim is usually randomised and appropriate control trials are often run. It is claimed that, in extremely large numbers of trials, subjects are able to influence the output of the RNG. Is this an effect of consciousness on a physical system?

I don't see why. The experiments demonstrate a correlation between the output of the RNG and the direction of aim specified to the subject by the experimenter. This is certainly mysterious, but the leap from this correlation to a causal explanation involving "the effect of consciousness" is so far unjustified. The controls done show that the subject is necessary but in no way identify what it is about the subject’s presence that creates the effect. It might be their unconscious intentions or expectations; it might be some change in behaviour elicited by the instructions given, it might be some hitherto unknown energy given off when subjects are asked to aim high or aim low. It might be some mysterious resonance between the RNG and the subject’s pineal gland. It might be almost anything.

As far as I know, no appropriate tests have been made to find out just what it is. For example, does the subject need to be conscious of the direction of aim at the time? Comments in the published papers suggest that some subjects actually do better when not thinking about the task, or when reading a magazine or being distracted in some other way, suggesting that conscious intent might even be counter-productive.

Perhaps this is not what is meant by consciousness here, but if not, then what is intended? Perhaps it is enough for the person to be conscious at all, or perhaps they have to be in an appropriate state of consciousness. In any case, to identify that the effect is actually due to consciousness, relevant experiments will have to be done. They might compare conditions in which subjects did or did not consciously know the target direction. Subjects might be asked on some trials to think consciously about the target and on others be distracted, or they might be put into different states of consciousness (or even unconsciousness) to see whether this affected the outcome. Such experiments might begin to substantiate the claim that consciousness is involved. Until then, the findings remain an unexplained anomaly.

Some parapsychologists have suggested to me that when they talk about consciousness affecting something they mean to include unconscious mental processes as well. Their claim would then be equivalent to saying that something (anything) about the person’s mind or brain affects it. However, if the term consciousness is broadened so far beyond the subjective then we leave behind the really interesting questions it raises and, indeed, the whole reason why so many psychologists and philosophers are interested in consciousness at all. If we stick to subjectivity then I see no reason at all why paranormal claims, whether true or false, necessarily help us understand consciousness.

The second reason I doubt that the paranormal power of consciousness will ever be proven is more theoretical. As our understanding of conscious experience progresses, the desire to find the "power of consciousness" sets parapsychology ever more against the rest of science (which may, of course, be part of its appeal). The more we look into the workings of the brain the less it looks like a machine run by a conscious self and the more it seems capable of getting on without one. There is no place inside the brain where consciousness resides, where mental images are "viewed" or where instructions are "issued" (Dennett, 1991). There is just massive parallel throughput and no centre.

Then there are Libet’s experiments suggesting that conscious experience takes some time to build up and is much too slow to be responsible for making things happen. For example, in sensory experiments he showed that about half a second of continuous activity in sensory cortex was required for conscious sensation, and in experiments on deliberate spontaneous action he showed that about the same delay occurred between the onset of the readiness potential in motor cortex and the timed decision to act (Libet, 1985) - a long time in neuronal terms. Though these experiments are controversial (see the commentaries on Libet, 1985; and Dennett, 1991) they add to the growing impression that actions and decisions are made rapidly and only later does the brain weave a story about a self who is in charge and is conscious. In other words consciousness comes after the action. It does not cause it.

This is just what some meditators and spiritual practitioners have been saying for millennia; that our ordinary view of ourselves, as conscious, active agents experiencing a real world, is wrong - an illusion. Now science seems to be coming to the same conclusion.

Parapsychology, meanwhile, is going quite the other way. It is trying to prove that consciousness really does have power; that our minds really can reach out and "do" things, not only within our own bodies but beyond them as well. Odd, then, that so many people think of parapsychology as more "spiritual" than conventional science. I think it could be quite the other way around.

With the welcome upsurge of interest in consciousness, and the number of scientists and philosophers now interested in the field, I look forward to great progress being made out of our present confusion. I hope it will be possible to bring together the spiritual insights with the scientific ones - so that research can reveal what kind of illusion we live in, how it comes about, and perhaps even help us to see our way out of it. As far as this hope is concerned parapsychology seems to be going backwards - hanging onto the idea of consciousness as an agent. This is the second reason why I doubt that evidence for psi, even if it is valid, will help us to understand consciousness.

I will therefore answer my original two questions with "probably not", and definitely "no".


Alcock,J.E. (1987). Parapsychology: Science of the anomalous or search for the soul? Behavioral and Brain Sciences, 10, 553-643 (plus commentaries by other authors).

Bem,D.J. and Honorton,C. (1994) Does psi exist? Replicable evidence for an anomalous process of information transfer. Psychological Bulletin 115 4-18

Blackmore,S.J. 1987 A report of a visit to Carl Sargent's laboratory Journal of the Society for Psychical Research 54 186-198

Braud,W. and Schlitz,M. (1989) A methodology for the objective study of transpersonal imagery. Journal of Scientific Exploration, 3, 43-63

Dennett,D. (1991). Consciousness Explained. Boston, Little, Brown.

Harley,T. and Matthews,G. (1987) Cheating, psi, and the appliance of science: A reply to Blackmore. Journal of the Society for Psychical Research, 54, 199-207

Honorton,C. (1985). Meta-analysis of psi ganzfeld research: A response to Hyman. Journal of Parapsychology, 49, 51-86.

Honorton,C. and Harper, S. (1974) Psi-mediated imagery and ideation in an experimental procedure for regulating perceptual input. Journal of the American Society for Psychical Research, 68, 156-168

Hyman,R. (1985). The ganzfeld psi experiment: A critical appraisal. Journal of Parapsychology, 49 3-49.

Hyman,R. (1995) Evaluation of the program on anomalous mental phenomena. Journal of Parapsychology, 59, 321-351

Hyman,R. and Honorton,C. (1986). A joint communique: The psi ganzfeld controversy Journal of Parapsychology, 50 351-364.

Libet,B. (1985) Unconscious cerebral initiative and the role of conscious will in voluntary action The Behavioral and Brain Sciences 8, 529-539. Commentaries 8, 539-566 and 10, 318-321

Marks, D. & Kamman, R. (1980). The Psychology of the Psychic, New York, Prometheus Books.

Markwick,B. (1978) The Soal-Goldney experiments with Basil Shackleton: new evidence of data manipulation. Proceedings of the Society for Psychical Research, 56, 250-277

Radin,D.I. and Nelson,R.D. (1989). Evidence for consciousness related anomalies in random physical systems. Foundations of physics, 19. 1499-1514.

Rhine,J.B. (1974) Comments: A new case of experimenter unreliability. Journal of Parapsychology, 38, 215-225

Sargent,C. (1987). Sceptical fairytales from Bristol. Journal of the Society for Psychical Research, 54, 208-218.

Utts,J. (1995) An assessment of the evidence for psychic functioning. Journal of Parapsychology, 59, 289-320

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