We explained to Mr. Rees that the most probable explanation was the Ideomotor Effect, which allows the human body to adjust very subtly to conditions, especially when the eyes give advance warning of something expected. The Ideomotor Effect can cause slight correcting motions of the muscles under various scenarios, like when using a ouija board, as one example. Mr. Rees seemed to accept the possibility, although he felt that in the past he had tested himself under similar controlled conditions. When asked, it was clear that he had never conducted a double-blinded test himself, and we suggested that subtle clues may have been given off by those that had placed the water for him to dowse. Also, he had only provided four containers for hiding the water during his own testing, thus limiting himself to a 1-in-4 possibility of success during every round strictly by chance.
Mr. Rees was then interviewed by Dr. John Suarez, resident psychiatrist in the IIG, and Mark Edward, a professional magician also of the steering committee. The post—demonstration interview is a standard part of the demonstration, used to determine how the applicant came to believe that they had their power(s), and if IIG's testing them under controlled conditions had made them view their powers any differently.
This test does not prove that dowsing itself is impossible, only that Mr. Rees failed to show dowsing ability under controlled conditions. The IIG remains open to testing other professed dowsers that come forward. As of this writing, Mr. Rees has stated that our group ran a fair test, and that he will continue to dowse as well as test his abilities on his own under more rigorous conditions. At this time, we have no idea if Mr. Rees has performed those tests.