Like the subject of pet psychics, the subject of dowsing is one I never thought it would be necessary to write about. This form of divination, like casting rune stones or knuckle bones and examining the entrails of sacrificial animals, is so clearly superstitious nonsense incompatible with science that it is hard to imagine even the most extreme advocates of alternative medicine taking it seriously.
Sadly, my ability to imagine the credulity of others has proven insufficient. A recent article in the Journal of the Royal Society of Medicine has chosen to treat dowsing, as employed by practitioners of another bit of folk magic, homeopathy, as a proper subject for serious scientific inquiry. (The paper is in the April issue, so I still secretly hope it was intended as an April Fool’s joke)
The authors describe dowsing this way.
Dowsing is a method of problem-solving that uses a motor automatism, amplified through a pendulum or similar device. In a homeopathic context, it is used as an aid to prescribing and as a tool to identify miasm or toxin load….Dowsing, also known as divining, water witching or rhabdomancy, has been defined as a ‘problem solving technique which apparently utilizes a motor automatism in conjunction with a mechanical instrument to obtain information otherwise unknown to the dowser’
I prefer this definition, from the Skeptic’s Dictionary:
Dowsing is the action of a person–called the dowser–using a rod, stick or other device–called a dowsing rod, dowsing stick, doodlebug (when used to locate oil), or divining rod–to locate such things as underground water, hidden metal, buried treasure, oil, lost persons or golf balls, etc. Since dowsing is not based upon any known scientific or empirical laws or forces of nature, it should be considered a type of divination and an example of magical thinking.
The authors of the dowsing study list several theories for how dowsing “works:”
Theories on dowsing come into three categories. Normal inference theory suggests that the dowser processes a large amount of information pertinent to the scenario at a subconscious level and moves the instrument accordingly. The physical theory sees the movement in the device being due to the amplification of minute reactions in the human body, with the precise nature of the reaction being unclear. It could be an electromagnetic field, or some form of vibrational energy.
According to the theory of psionic medicine, every living thing and inanimate object is continuously vibrating at a molecular level. This vibration is sensed subconsciously by the dowser, and it is then amplified through the pendulum or other dowsing device. Some proponents of this explanation suggest that this sense originally developed as a survival tool because it enabled individuals to find water. As the vibrational pattern can change with disease, it is purported to be a useful tool for clinical practice.
Finally there is the psychical theory which suggests the dowser employs some form of extrasensory perception.
They have, however, omitted one very important theory:
The ideomotor effect refers to the influence of suggestion or expectation on involuntary and unconscious motor behavior. The movement of pointers on Ouija boards, of a facilitator’s hands in facilitated communication, of hands and arms in applied kinesiology, and of some behaviors attributed to hypnotic suggestion, are due to ideomotor action… The term “ideomotor action” was coined by William B. Carpenter in 1852 in his explanation for the movements of rods and pendulums by dowsers, and some table turning or lifting by spirit mediums (the ones that weren’t accomplished by cheating). Carpenter argued that muscular movement can be initiated by the mind independently of volition or emotions. We may not be aware of it, but suggestions can be made to the mind by others or by observations. Those suggestions can influence the mind and affect motor behavior.
In other words, dowsing is yet another example of people fooling themselves into believing that outside forces are accomplishing actions which, in fact, they are generating through their own unconscious need to see what they want and expect to see.
Dowsing has been studied a number of times, in as scientific a way as it is possible to study magic. The studies have pretty consistently shown that with any reasonable controls for bias (such as blinding of the dowsers), dowsing doesn’t work. Dowsers have not demonstrated the ability to find anything with an accuracy better than chance if they don’t know in advance where it is.
Naturally, dowsers often complain that this failure is due to the effects of the testing situation, which in some undefinable way muddies the psychic waters so they can’t perform. In the current study, this concern was accommodated.
In discussions before the study began, dowsers expressed concern that the pressure of an experimental situation might be detrimental to the dowsing sense. For this reason the study packs were mailed to the volunteers for evaluation in their own time in relaxed conditions…there was generally a high level of confidence in the responses (n=99, 63.5%), which suggests that we were successful in making the dowsers feel relaxed about the study.
So how was the study conducted? Well, six registered homeopaths with experience in the medical applications of dowsing were sent 26 pairs of unlabeled bottles containing either a homeopathic solution (a 12C preparation of Bryonia which, as the authors put it, “is ‘ultramolecular’…a dilution of 10-24…very unlikely to contain any molecule of the starting material”) and a placebo (prepared in an identical way except from distilled water instead of the Bryonia mother tincture).
In other words, they received two bottles of water one with magic powers and one without. They also received a pair of labeled bottles to practice on. They were then instructed to identify the magic water (I mean the homeopathic remedy) by magic (I mean dowsing).
And how did they do? Of 156 selections between pairs of bottles,
48.1% responded correctly (n=156; 95% confidence interval 40.2%, 56.0%; P=0.689)….percentage of correct responses ranged from 34.6% (n=26; 95% CI 15.77%, 53.4%; P=0.170) to 61.5% (n=26; 95% CI 42.4%, 80.6%; P=0.327). Of responses given with high confidence, 45.0% were correct (n=99; 95% CI 35.6%, 55.3%; P=0.421).
So, almost eerily close to perfect chance levels, with performance no better for those who were confident in their choices versus those who knew they were guessing. In fact, “High confidence was slightly more associated with an incorrect response.”
Since this is science, the authors made some comments about the potentially inappropriate application of statistics (using a method which assumes independent samples for samples that are actually associated), but as they put it,
The data were in fact so far from showing any type of effect of dowsing that the assumption of independence was probably met, so the more appropriate clustered analysis is unlikely to show a different effect.
So does this close the book on “medical dowsing?” Undoubtedly not. It does serve, however, as an excellent illustration of the premise of this blog. The application of scientific study to the highly implausible only seems justifiable if resources are unlimited or if the results, when negative, will influence peoples belief in implausible practices. Neither of these conditions is met in the real world.
In an ideal world, it might make sense to study every idea no matter how unlikely to be truth based on established knowledge, since once in a great while crazy ideas actually turn out to be right. But in the real world, they usually don’t. Since we have to conserve our resources and use them as efficiently as possible in investigating potential therapies, and since scientific evidence against magic does little to reduce people’s belief in magic, conducting and publishing studies like this seems a pointless and unconscionable waste of time and effort which only conveys an inappropriate sense of legitimacy to the hypotheses being studied. On the other hand, it is entertaining.