Why it Feels Like Dowsing Works

I'm 56, two years ago I discovered I can use a twig and dowse for water. I can prove this, video experiment etc.I wouldn't have believed it myself and still have no idea WHY it works but it does. Don't answer this if you don't believe me when I say it works. But how or why does it work??
- Tim Harvey (age 56)
UK

There's no evidence that dowsers can detect water or anything else better than random chance (and there's plenty of evidence that they can't).

However, I believe that you think it works. The reason why is fascinating on its own: your brain is tricking you. You're experiencing a well-documented effect called the ideomotor phenomenon. When you imagine something happening and form a mental image—​in this case, the dowsing stick moving—your body can react by actually making that thing happen, with very small motions that may feel involuntary or unconscious. Combine that with confirmation bias, the tendency that most people have to focus on examples that support what they want to believe, and you could easily convince yourself that something mystical is happening.

You can experiment with this phenomenon yourself using a pendulum. An object tied to a string will work. Holding the string between your thumb and forefinger, you can make the pendulum swing back and forth with a very subtle motion of your fingers. Tell yourself that the pendulum is going to swing in the north-south direction when you're asked a question to which the answer is "yes," and that it's going to swing in the east-west direction when the answer is "no." Try asking yourself some questions (or get someone else to ask). Visualize which way the pendulum should swing, but don't deliberately move it. Does it seem like the pendulum is giving the correct answers?

Rebecca H.

(published on 08/01/2016)