Jan 07 2008

Looking for ESP in the Brain

A recently published study uses functional MRI to look as brain function in response to possible extra-sensory perception (ESP) stimuli. The study was negative, leading the authors to conclude:

These findings are the strongest evidence yet obtained against the existence of paranormal mental phenomena.

While that might be overstating it a bit, it was an interesting new approach to the question of ESP. Study authors, Samuel Moulton, a graduate student in the department of psychology at Harvard University, and Stephen Kosslyn, also at Harvard, decided to look for ESP in the brain by imaging subjects with fMRI during ESP and non-ESP signals. The ESP signals consisted in one trial of an emotionally close person looking at the target image and attempting to telepathically send the image to the subject, who was also looking at the image. A second trial involved a computer screen in another room with the target image (testing clairvoyance). And a third trial involved displaying the image to the subject again after the trial (testing precognition).

The premise of the study (which is well established) is that the brain responds less to stimuli that it has seen before (even subliminally), and more to stimuli that it anticipates. So the authors hypothesized that if the subjects were exposed to the target stimuli through telepathy or clairvoyance (even if they were not consciously aware of it) their brain should display an increased response. In all the trials there was no difference in brain response between subjects with and without an ESP stimulus.

What does this study actually show? That question cuts to the current difficulty of ESP research – namely that no one knows what ESP is supposed to be, and this cuts both ways. For example, in this study, the authors had to make many assumptions about how ESP works in order to decide what should happen (increased or decreased brain response to stimuli) in response to ESP. Their hypotheses are all reasonable, and the fact that they are negative is one more piece of evidence that casts doubt upon the existence of psi. But it does not, and cannot, rule out any ESP phenomena. That is primarily because ESP is not currently constrained mechanistically.

In other words, there is no scientific model for how ESP can work – no mechanism. Some proponents make hand-waving speculations about quantum entanglement or cosmic consciousness, but these are ultimately meaningless gibberish. There is no proposed mechanism for ESP that amounts to a reductionist model based upon established physics or biology. No one has even established any physical features to ESP – meaning that it displays consistent characteristics, such as decreasing with distance, or being blocked by dense substances, or anything. There has been zero progress in zeroing in on what ESP might be as a physical phenomenon.

The simplest explanation for this utter lack of any progress characterizing a possible mechanism for ESP is that ESP does not exist. This new study mostly just adds to the string of negative studies looking for a possible mechanism or even physical sign of ESP. This, unfortunately, will never give us ultimate closure because it is impossible to prove a negative – that no type of ESP exists anywhere, anytime. But the longer we look with negative results, the more confident we can become in the conclusion that ESP probably does not exist.

The lack of a possible or even hypothetical mechanism for ESP also means that ESP research is limited to anomaly hunting. All studies that propose to look for ESP (for example the research of Dean Radin or Rupert Sheldrake) are not looking for ESP (because no one knows what ESP is) but rather are looking for anomalies. In fact some researchers more honestly label what they are looking for as “anomalous cognition.”

Let’s take the Ganzfeld experiments, for example. This is an automated test for clairvoyance- the ability to remotely view a target. Subjects were given four pictures to choose from, one of which was the target picture, displayed in another room. Random guessing would produce a hit rate of 25%. Some Ganzfeld researchers claimed hit rates much higher – although the Ganzfeld experiments ultimately failed to be replicated and under tight methods eventually the effect size shrunk to near zero.

Without getting into all the details, my reading of the ESP literature is that there is yet to be an experiment that survives the process of peer-review and replication. Even proponents have to admit that ESP researchers have not yet come up with a trial design that produces a reliable signal. Signals over time tends to go away and ultimately fail to be replicated – although there are always new trial designs coming down the pike. So as yet there is not even an anomaly to explain.

But let us say, hypothetically, that an ESP study demonstrates a reliable signal. That would not demonstrate ESP, it would only demonstrate an anomaly. In so-called ESP studies (again, more properly termed “anomalous cognition”) the design essentially is looking for some effect that cannot be explained by known means. So the definition of an ESP signal is always a negative one – an apparent effect that has no other explanation. This, of course, requires absolutely tight methodology (and the smaller the effect size the tighter the methods have to be), because you cannot prove a negative – in this case that there was no other cause for the apparent signal. The conclusion that there is no non-ESP cause is only as good as the degree to which all potential variables in the study were anticipated and controlled for.

Looking for anomalies is a legitimate part of scientific exploration – but it should be considered only the beginning of the process, not the conclusion. You cannot prove the existence of a specific phenomenon simply by pointing to an anomaly – that would constitute an argument from ignorance logical fallacy. In order to establish that ESP exists researchers would need to find a reliable anomaly and then show that the anomaly has certain features. These features would then suggest possible mechanisms, leading to specific hypotheses that can be tested. Eventually an underlying mechanism would come to light that explains the features of the anomaly. Hopefully research would also reveal a signature of ESP – some feature of the anomaly that is unique or at least highly suggestive of ESP and can be used as a positive signal for the presence of ESP.

None of this has happened. ESP researchers are stuck at step one – find an anomaly. They keep claiming that they have succeeded in this step, but so far their claims have not survived adequate review and replication. While proponents are still arguing about step one, the undeniable fact is that there is no research or evidence which takes ESP beyond step one, characterizing a new phenomenon or pointing the way toward a credible mechanism.

Proponents typically argue that the mechanism for ESP is simply too far outside any current scientific paradigm. That may be true (again, one cannot prove a negative) but that is not an argument to accept a claim for ESP. It is just another argument from ignorance. Until ESP is brought within what is known and established, we have nothing.

The history of science has taught us that alleged phenomena that are elusive to demonstrate, have no known mechanism, and display no positive features that can be used as a marker or signature – probably do not exist. That is the conclusion demanded by the principle of parsimony. A century of ESP research has displayed all the features of a non-existent phenomenon. This latest study adds one more strike to this long history.

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