The Ideomotor Effect — Or How Science Explains Dowsing

It’s neuroscience, not magic

Image by the author.

“Pendulum, pendulum in my hand, am I the baldest of them all?”

I look at the pendulum that I’m holding suspended from a string and… Oh, whow! The pendulum is actually swinging from left to right, unambiguously telling me that I am the baldest!

Hooray, I guess?

But wait! I shouldn’t be that superstitious. Maybe there’s a trick. Maybe this is all nonsense. So let me be a good skeptic and investigate:

“Pendulum, pendulum in my hand, is this for real?”

I carefully observe the weight dangling from the string and the answer is… yes? Huh, okay, I guess that settles it.

What’s dowsing?

For centuries morons — I mean, my superstitious German ancestors — have been making fools of themselves by engaging in a practice known as dowsing. They’ve been asking questions to handheld pendulums and interpreted their movements as answers from spirits, God, or their dead grandfather Hans. Not only that, but they also participated in water dowsing, which consists in confidently striding through a field with a Y-shaped wooden branch until it slaps you in the face to tell you the location of groundwater — or where a mole might have taken a…