The dope on dowsing
Greg Spearritt considers a commonly-held contemporary claim to highlight the peril inherent in sidelining science and reason.
I’d never heard of Criss Angel until someone in one of our local SOFiA meetings made an extraordinary claim. As I recall, I had made a flippant statement to the effect that people can’t levitate. “With one exception”, said this person. They were serious.
That took me, inevitably, to the internet where I did indeed find Criss Angel levitating. (Watch for yourself.) It became clear, however – a matter of seconds later – that far from claiming to be able to genuinely levitate, Criss Angel was in fact a magician, aka a performer of magic tricks. He can also walk on water, bring stuffed animals to life, swap the (live) torsos of a man and woman on a park bench… and much more.
Extraordinary claims, as they say, require extraordinary evidence – and not a little critical thought.
That dowsing (‘water divining’, ‘water witching’ or radiesthesia) works is one extraordinary claim that is particularly widely believed even in contemporary Australian society. When current CSIRO CEO Larry Marshall won his position in 2014 he created controversy by suggesting the organisation spend money investigating dowsing. (It won him the Australian Skeptics Bent Spoon Award.) I personally know many, intelligent people all, who swear by dowsing. In all cases their belief is based on knowing someone they trust who claims to be able to do it, or on having seen someone do it.
Most commonly, dowsing is used to find subterranean water. Some dowsers also believe they can divine gold and other minerals, and some tackle illness, graves, bombs and even guilt – the Dowsing Society of Victoria claims dowsing has “an unlimited range of uses” – but I’ll restrict myself to the water version here.
Stereotypically, a forked stick or bent wire/s is used by dowsers. These move (downwards, or outwards, or they cross over) when the presence of underground water is detected, without the dowser consciously exerting control.
Usually no attempt is made by dowsing practitioners to explain this movement and its connection with what it purports to detect, leaving the mechanism in the realm of the paranormal or even the spiritual.
The movement of the dowsing rods is genuine. In the opinion of many scientists, however, it arises from a category of muscle movement that science has long recognised: ideomotor activity. The Dictionary of the American Psychological Association describes it this way:
“movement, in some cases elaborate, related to ongoing thoughts but produced without volition. Ideomotor activity explains a variety of phenomena, including gestures during conversations.”
Ideomotor activity was fingered by famous English scientist Michael Faraday as the cause of ‘table tilting’, a craze in Victorian times whereby tables during seances would move around the room. It’s also been posited as the cause of automatic writing and the mechanism behind Ouija board messages.
It seems that whether you ‘believe’ or not, dowsing rods can indeed move in your hands. So let’s assess the evidence for the effectiveness of dowsing.
Evidence vs anecdote
An axiom among the scientifically-minded is that anecdote is not evidence. I subscribe to that view. If anecdote were substantive evidence, we would have to credit a bewildering array of ideas which are demonstrably false. Received wisdom when I was a child was that sunburn was best dealt with by standing under the hottest shower you could stand. I can attest that you definitely felt better when you turned off the shower! Health professionals now recommend cooling the skin as soon as possible.
We’re currently witnessing an outbreak of strongly-held bad (wrong) ideas about COVID and its treatments, often based on anecdote, but that’s nothing new. Miracle stories have been with us forever, and personal accounts abound about alien abduction, ghosts and the power of pyramids (though this last seems unaccountably out of vogue since von Däniken faded from the scene).
This is not to say someone’s personal story should be ignored or that it’s necessarily got the facts wrong. Personal experience is powerful. It’s just that it’s low on the reliability scale when it comes to avoiding false conclusions. We humans are particularly skilled at fooling ourselves.
Hence science. If a significant idea can be tested in a scientific manner, in my opinion it should be. The fewer false things we believe, the better.
There’s a great deal of evidence from field reports and trials of dowsing.
The strongest evidence in favour is from two German studies. One is a report from 1995 of field work in a number of countries over a ten-year period and makes much of a success rate of 96% for drillings in Sri Lanka. The report’s author, University of Munich physicist Hans-Dieter Betz, says this is far above the rate to be expected by conventional techniques and concludes: “Provided that certain conditions are met, the results obtained show the dowsing technique to be a serious alternative for ground-water prospecting”.
Difficulties with this report are discussed by skeptic and philosopher Robert Todd Carroll. He notes that Betz ruled out chance and the use of landscape and geological features by dowsers as explanations for their success. We have no idea, therefore, whether the dowsers were doing something amazing or simply looking for low spots and where the grass was greener (as, Carroll notes, the late pseudo-science buster James Randi has pointed out). In any case, Sri Lanka is a country which receives up to 5m of rainfall annually. Carroll observes, further:
“There are some puzzling elements to Betz’s conclusions… Most of his claims concern a single dowser named Schröter. Who observed this dowser or what conditions he worked under remain unknown. Betz is a physicist and what knowledge he has of hydrogeology is unknown.”
The second German study – also involving Betz – tested over 500 dowsers in more than 10,000 double-blind trials. It was set up by physicists in a barn near Munich in 1987 and 1988. Although the researchers concluded that they had discovered “a real dowsing phenomenon”, it turns out that the performances of a mere handful of the 500 dowsers were considered significant, and even they couldn’t reliably reproduce their success. Indeed, one close assessment of the Munich barn experiments concludes they “can and should be considered a decisive failure”. (An instructive video demonstrates the results.)
I could locate a third study claiming to be favourable to dowsing as a means of finding leaks in hydraulic networks. It includes the information that “first the location of the leak is determined using Reynolds’ theorem, [and] finally, the existence of the leak is corroborated with the rods”. The idea that dowsing rods tend to move where a diviner expects to find water is discussed below (‘So what’s going on?’). This study would have much more force if the ‘rods’ were used (successfully) to determine the leak locations in the first place.
Evidence against – tests
Trials, studies and field reports showing no evidence of the effectiveness of dowsing – beyond what would be expected by chance – are legion.1.
This is not new information. In a foreword to a 1917 paper published by the United States Geological Survey, one O. E. Meinzer stated, “It is doubtful whether so much investigation and discussion have been bestowed on any other subject with such absolute lack of positive results.”
In more modern times, carefully controlled double-blind tests have been held involving pipes, often buried, through which water is randomly run. Dowsers inspect the apparatus beforehand and agree they will be 80-100% accurate in determining where the water is.
There has long been on offer (from skeptics in Australia and from the James Randi Foundation in America) large cash prizes for anyone who can successfully demonstrate dowsing under rigorous test conditions. Many have tried, but no-one has ever won the money.
In spite of dowsers (initially) claiming confidence in their abilities in controlled tests, it has been argued that such trials are artificial, and therefore don’t allow for whatever might actually be operating in real-world dowsing situations. So what is the (non-anecdotal) evidence in the field?
Evidence against – field reports
Individual reports of failure to divine water are difficult to come by. There isn’t much incentive, of course, for dowsers themselves to own up, and landowners who’ve paid for such a service may be reluctant to admit failure. Exactly what constitutes failure is another relevant question:
If the search is not successful he [sic] tries again and again on other ground. Should a ‘find’, be the final result, the whole countryside bears witness to his magical powers; should failure attend all the excavations made by his indications, the ready explanation is to hand that his employers did not excavate deeply enough – that they lost patience and faith when on the verge of success.
Perhaps, though, complete failures aren’t all that common. It’s a fact that in many places not striking water may be harder than finding it.2. Indeed, it’s been compared to hiring someone to find which window to open to locate some air. To boot, when a dowsing rod is used, presumably bores are not drilled where it doesn’t indicate water – even though there may be good water at those sites.3.
You might also expect it would be widely employed for military purposes. A review of British military hydrogeology in World War II tells us that, while not official policy, dowsing was indeed sometimes used to site wells in the Middle East. The results? Major-General Tickell, Director of Works for Middle East Forces, said it plainly in 1942:
Our experience has been, without one shadow of a doubt, that the water diviners’ assistance has been absolutely worthless. Not only in their percentage of successes below what would have been expected by mere chance, but their ability to distinguish between saline and non-saline water does not exist. They have been given a fair trial and we have come to the conclusion that they should be prohibited from even offering gratuitous advice.
Tickell wryly notes that, in spite of official policy, “It is… impossible to prevent individuals… wandering about with hazel twigs”. 4.
To quantify the matter, he tells us:
During the last 2.5 years some 20 miles [32 km] of boreholes have been drilled in [the] Middle East. Of these drilled in search of water 60% were successful in an area remarkable for its lack of drinking water…. The first point that has emerged is that water diviners should on no account be employed. From time to time Officers, Members of Dowsing Societies, have managed, by virtue of their position, to influence the siting of boreholes, particularly where geological advice was not obtainable. The percentage of successes in these cases is only 13, i.e. 87% failures. 5.
Further, it’s reported that the US 5th Army in Italy obtained the services of a water diviner in 1945 to locate groundwater. At the end of the dowser’s task it was reported that ‘Conclusive results on water divination have not been attained. Adequate water was not found’. 6.
Perhaps the clincher of all the evidence on dowsing comes from data collected between 1918 and 1945 in NSW. At that time, the then NSW Water Conservation & Irrigation Commission was obliged to sink a bore wherever a landholder wanted. Detailed data was kept on the 3,638 bores drilled in those years. Some landowners, inevitably, used dowsers to pinpoint the drilling location. W. H. Williamson in ‘The history of hydrogeology in Australia’ presents the data. About half of the bores, he says, “were on divined sites, and in spite of the ‘advantage’ of having been divined, there were twice as many failure bores on such sites than on sites not divined.”
So what’s going on?
If it is indeed the ideomotor effect that moves the dowsing rod, key to the movement is belief itself, and perhaps knowledge, even if it’s not conscious. This idea has some experimental support.
Popular Mechanics reports:
a team at the University of British Columbia found that when subjects did not know an answer to a question like ‘What is the capital of Hungary?’ but had to guess from among multiple choices, their guesses were 50 percent accurate. But when they used a Ouija board to answer, the ideomotor effect kicked in and their answers were 65 percent accurate.
This may explain why so many people believe in dowsing, and why it can work better than chance. If there are cues that you have not noticed consciously, but which have been tagged by your unconscious mind, dowsing may reveal that unconscious insight.
The 1989 dowsing tests by the Australian Skeptics provided evidence that “that the rod moves even when no object is present – as long as the diviner believes it is present.”
A 2013 article in the American journal Teaching of Psychology describes an activity designed to enhance the ability of students to think critically. Students are shown metal rods crossing over when they’re passed over a cup of water, but not reacting when they pass over a cup of sugar. When students themselves try it the same phenomenon results, “even after we covered the cup and surreptitiously replaced it with the cup containing sugar (illustrating ideomotor action)”.
Challenging firmly-held beliefs
Belief in dowsing among the proponents I know seems to be largely a matter of ‘belief-in’: that is, faith in a person who claims this ability, often a relative. That’s very hard to argue against, because suggesting they’re wrong can seem like a slight on that person’s character or honesty. Yet it seems that many or even most who claim they can dowse are actually sincere about it.
It may be argued that I myself have a firmly-held view, and it’s true. My belief that dowsing is not effective, however, is based on evidence. I will readily change it if I am presented with solid evidence and sound argument demonstrating that I’m wrong. As Keynes is sometimes credited with saying, “When the facts change, I change my mind. What do you do?”
I think it fair to say most people don’t adequately understand science. Indeed, a 2010 study in the International Journal of Science Education showed that even many university science students often demonstrate a lack of understanding – including specifically with reference to water divining – about the demarcation between science and pseudo-science.
Why does it matter?
If someone holds a belief – one which can be scientifically tested – so dearly that no amount or quality of evidence will affect it, we are potentially in dangerous waters. Dowsing can cause wastage of time and money and poorer results than scientific methods in seeking water. As noted earlier, however, people dowse for many things. Divining for bombs is in another category altogether. It’s a pseudo-science that has caused considerable loss of life. (See also here and here.)
If you won’t be persuaded by sound evidence on dowsing, why would you listen to the science on Covid-19? Or climate? We’re currently seeing the consequences of ignoring the evidence on both these issues. It has serious consequences, regrettably, for all of us.
Reason is not the be-all and end-all. But I fear for a world that refuses to use it.
- See, for example, R. A. Foulkes (1971) ‘Dowsing experiments,’ Nature, 229, pp.163-168); M. Martin (1983-1984) ‘A new controlled dowsing experiment’, Skeptical Inquirer, 8(2), 138-140; J. Randi (1979) ‘A controlled test of dowsing abilities’, Skeptical Inquirer, 4(1). 16-20; D. Smith (1982) ‘Two tests of divining in Australia’, Skeptical Inquirer, 4(4). 34-37; and Gregory, J. W. (1929) “Water Divining,” Annual Report of the Board of Regents of the Smithsonian Institution, 1928, pp.335-340.
- “In a region of adequate rainfall and favorable geology, it is difficult not to drill and find water!” – U.S Geological Survey (1977) ‘Water Dowsing’ (DOI 10.3133/7000104). See also U.S Geological Survey (1988) ‘Dowsing’.
- As noted by Captain K. D. Nelson (1969), ‘Water Divining: Witchcraft or Fact?’ in ed. C. F. Coady, Army Journal, No. 245, p.50. See also the unpublished report from the Geological Survey of Victoria, 1960.
- Rose, E.P.F. (2012) ‘Groundwater as a military resource: Development of Royal Engineers Boring Sections and British military hydrogeology in World War II’, Geological Society London Special Publications 362(1):105-138, p. 133 (DOI:10.1144/SP362.7)
- Ibid, p. 134
- Ibid, p. 134
Disclaimer: views represented in SOFiA articles are entirely the view of the respective authors and in no way represent an official SOFiA position. They are intended to stimulate thought, rather than present a final word on any topic.
Photo: wikihow.com (CC BY-NC-SA 3.0)