Believing Bullshit: How Not to Get Sucked into an Intellectual Black Hole (22 page)

By using a combination of hot and cold reading, professional magicians can fake everything that supposedly genuine psychics can apparently do—often fooling audiences into believing they are genuinely psychic before revealing the truth. In fact, it is striking how often the methods of many supposedly genuine psychics resemble those of honest cheats.

However, it would be a mistake to conclude that everyone
who believes they are psychic—and who presents himself or herself as a psychic—is a deceiver. Several years ago, a friend and I played a simple mind-reading trick on another friend of ours. It's a simple trick you can try yourself. One person holds up a playing card and then mentally “transmits” the color of the card to the other person, who has to guess the color. To the amazement of onlookers, the guesser keeps getting it right. It looks like they are “mind reading,” but actually they are using a simple code: when the person holding the card says “OK,” the card is black, and when they say “Right,” it's red. It's a fairly obvious deception, and it's astonishing that people fall for it. But many do, especially if you set up the trick so that it seems to emerge as a bit of spontaneous larking about. Throw in a few misses to give the scenario credibility, and the trick works better still.

What was interesting on this occasion was that, after impressing our victim with our psychic powers, we decided to test her to see if she, too, could read the mind of the card holder. She found, to her astonishment, that she could. She got more and more excited about her amazing psychic ability, until we finally had to disappoint her by revealing the truth—that she was merely subliminally picking up on the OK/Right code.

Just like my friend, some psychics lacking any genuine psychic ability may nevertheless sincerely believe they are psychic. They may be picking up on all sorts of entirely natural signals and clues without realizing they are doing so.

We may also unwittingly provide psychics with information through our body language. Consider the strange case of Clever Hans, a horse that could apparently perform mathematical calculations—tapping out the answers with his hoof. In 1907, psychologist Oskar Pfungst conducted an investigation into the horse's alleged mathematical abilities and discovered that the horse was not doing math but picking up on the very subtle reactions of his human trainer. The trainer was, without realizing it, cueing the horse when to stop tapping. When the trainer did not know the answer, it turned out that the horse didn't either. The
Clever Hans effect, as it became known, illustrates how we can “leak” information without realizing it.

“TELL ME A STORY”

We have conducted a brief survey of some of the main ways anecdotal evidence for the existence of psychic powers, ghosts, alien abduction, monsters and so on can be generated. It indicates why such evidence is almost entirely worthless. You will remember in “
But It Fits!
” that we said evidence supports a hypothesis to the extent that
the evidence is to be expected if the hypothesis is true, but not particularly expected otherwise.
The evidence has to be, in a certain sense, “surprising.”

The problem with anecdotal evidence for such extraordinary claims is that, knowing what we do about how such testimony tends to be generated, a great deal of it is to be expected
anyway
, whether or not the claims happen to be true. The existence of quantities of such anecdotal evidence is not, then, good evidence for the truth of such extraordinary claims.

Anecdotal evidence may be largely worthless as evidence, but it can be highly persuasive. Humans love a story, especially if it's shocking, weird, or emotionally arresting. We enjoy comedies, tragedies, stories of wrongs righted, of revenge, of ghosts, of aliens. One reason we find such stories appealing is that they tap into our tendency to feel empathy with others. We enjoy imaginatively putting ourselves in the subject's position, imagining how it must have felt to exact that bloody revenge, to see a ghost, or to be abducted by aliens. The more emotional impact the story has, the more memorable it is.

As a consequence, a juicy story can psychologically trump a dry statistic, even when the statistic is rather more informative. The result of a double-blind clinical study of the efficacy of prayer is a dull set of figures easily forgotten, whereas a handful of emotionally arresting anecdotes about prayers answered may resonate with us for a long time.

THE AMAZINGLY PERSUASIVE POWER OF ACCUMULATED ANECDOTES

Pulling several anecdotes together can be particularly persuasive. A shower of anecdotes often explains why people become convinced that certain medical treatments are effective when they are not.

Bloodletting, popular from antiquity until the late nineteenth century, was used to treat almost every disease. In 1799, George Washington asked to be bled after he developed a throat infection. He died after large quantities of blood were removed. Benjamin Rush, a physician and one of signatories to the Declaration of Independence, was, like most of his contemporaries, entirely convinced that removing significant quantities of blood from patients helped cure many ailments. Rush, like other physicians, believed in the efficacy of bloodletting entirely on the basis of anecdotes about people being bled and then recovering. Here he cites two examples:

I bled a young man James Cameron, in the autumn of 1794, four times between the 20th and 30th days of a chronic fever, in consequence of a pain in the side, accompanied by a tense pulse, which suddenly came on after the 20th day of his disease. His blood was sizy. His pain and tense pulse were subdued by the bleeding and he recovered. I bled the late Dr. Prowl twelve times, in a fever which continued thirty days, in the autumn of the year 1800. I wish these cases to be attended by young practitioners.
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It was not until Parisian doctor Pierre Louis conducted a controlled experiment in 1836—treating one group of patients with pneumonia with aggressive bloodletting, and another group with modest bloodletting—that the truth began to be revealed. The number of patients who died after aggressive bloodletting turned out to be greater.

Consider homeopathy. In their book
Trick or Treatment
, Simon Singh and Edzard Ernst (the latter is both a professor of
medicine and a trained homeopathic practitioner) conclude of their assessment of the scientific evidence regarding homeopathy that “it would be fair to say that there is a mountain of evidence to suggest that homeopathic remedies do not work.”
¹⁰
So why do people
think
they work? Because of numerous anecdotes about the efficacy of homeopathy. These anecdotes are, in reality, a result of people just getting better anyway, the placebo effect, and other factors such as conventional medicines also having an effect, subjects not wanting to disappoint those interviewing them, and so on.

Many people also believe in the power of intercessionary prayer to help people through medical crises. In 2006, the
American Heart Journal
published the results of a 2.4 million-dollar experiment involving 1,802 heart-bypass patients, conducted under the leadership of Herbert Benson, a cardiologist who had previously suggested that “the evidence for the efficacy of intercessionary prayer is mounting” (so he was hardly biased against the claim that prayer works). The results were clear-cut: prayer had no beneficial effect on the patients.
¹¹
Another large-scale trial of patients undergoing angioplasty or cardiac catheterization also found prayer had no effect.
¹²
Unsurprisingly, such studies don't convince all those who believe in the power of prayer. After these studies, Bob Barth, spiritual director of a Missouri prayer ministry involved in the Benson prayer experiment, said, “A person of faith would say that this study is interesting, but we've been praying a long time and we've seen prayer work, we know it works, and the research on prayer and spirituality is just getting started.”
¹³

How did Bob Barth “know” prayer works? In the same way Benjamin Rush “knew” that bloodletting worked. On the basis of anecdotal evidence—that's to say, various cases in which the treatment was “seen to work.”

CHRISTIAN SCIENCE

It's often said that “the plural of anecdote is not data.” And yet a pile of anecdotes can be made to
look
very much like solid scientific data. Attempts have even been made to build a science on the basis of anecdotal evidence. I will finish this chapter with a brief look at just such an attempt—Christian Science.

As Caroline Fraser, a former Christian Scientist herself, explains in her book
God's Perfect Child
(on which much of this section is based), Christian Scientists believe that they have rediscovered Christianity by rediscovering the “
exact method and means
by which Jesus healed. Only Christian Scientists believe they can duplicate those healings systematically and repeatedly over a lifetime.”
¹⁴

According to Mary Baker Eddy, the founder of the Christian Science movement, matter does not exist and disease is a product of the mind. A Christian Science practitioner's training typically involves two weeks of religious instruction. Practitioners are not trained to diagnose illness, and in fact they do not even believe in the reality of illness. The treatment carried out by trained practitioners of Christian Science is primarily prayer.

How do Christian Scientists know they have discovered methods that work? Because of the “scientific” evidence they have amassed over the years—tens of thousands of published testimonies of cases in which the methods of Christian Science have been applied and people have subsequently recovered. The “science” in Christian Science is meant literally. The suggestion is that the thousands of testimonies or anecdotes that the movement has accumulated over the years constitutes solid, statistical evidence that Christian Science works.

By 1989, around fifty-three thousand testimonies had been published in Christian Science periodicals. Early on, the cured were allowed to write up their own cases. More recently, Christian Science publications have prefaced such testimonials by saying:

The statements made in testimonies and articles with regard to healing have been verified in writing by those who can vouch for the integrity of the testifier or know of the healing. Three such written verifications or vouchers are required before testimony can be published.
¹⁵

While this might strike some as being very “scientific,” the appearance of scientific rigor is misleading.

Notice, first of all, that the Christian Science movement
ignores all cases of failure.
It counts only its “hits” and ignores all its “misses.” Extraordinarily, there are no records of those who died after having received treatment. In their “Empirical Analysis” conducted by Christian Scientists of over seven thousand treatments, the authors admitted that the study “does not provide comparative cure or mortality rates, nor does it consider cases in which healing prayer has not been effective.”
¹⁶
This fact, all by itself, renders the evidence more or less worthless.

Worse still, many of the testimonials look very dubious indeed. In 1954, the academic R. W. England of the University of Pennsylvania published his analysis of a sample of five hundred letters published in the
Christian Science Journal
testifying to the power of Christian Science to heal. As Fraser notes, England found that the self-diagnoses of Christian Scientists were often unreliable:

The number of cancers, tumors, broken bones, and cases of pneumonia and acute appendicitis which were self-diagnosed by the writers seemed large…. It seems likely that most of the more dramatic cures are due simply to mistaken diagnoses. In scores of letters the writers describe how they broke their skulls, dislocated organs, awoke in the night with pneumonia, decided mysterious lumps were cancers, or found themselves in other ways serious victims of mortal mind. Their next move was to begin divine treatment, with or without a practitioner's aid. Elated and gratified when the skulls mended, their organs returned to place, their pneumonia and cancers vanished, they wrote letters of testimony to the Journal.
¹⁷

Moreover, most letters concerned fairly trivial—sometimes psychosomatic—conditions that tend to get better anyway:

Most conspicuous was an apparent ignorance of or indifference to the natural healing powers of the human body. Thus, a vast number of minor ailments, ranging from athlete's foot to the common cold, were treated and cured by the application of Divine Truth. Furthermore, there is, among the 500 communicants, considerable attention given to types of disorders so insignificant as to be of practically no consequence so far as one's daily life is concerned. Chapped hands, lone warts, a burned fingernail, hangnails, vague fleeting pains, a momentary dizziness were not infrequently the “healings” for which testimony was given.
¹⁸

It should be fairly obvious by now why the “scientific evidence” for the efficacy of Christian Science is no such thing. It's just a vast collection of anecdotes—tens of thousands of them—anecdotes of a sort that we might well expect to be produced by the kind of mechanisms described in this chapter, whether or not Christian Science actually works.

If Christian Science really worked, then that fact could be established by a controlled experiment, as scientist Richard Feynman points out in his book
The Meaning of It All
:

There is, in fact, an entire religion that's respectable, so called, that's called Christian Science, that's based on the idea of faith healing. If it were true, it could be established, not by the anecdotes of a few people but by careful checks.
¹⁹