Copyright 2015 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
Dowsing: Truth or Trickery?
By NBC News
(NBC News) A prominent California winemaker is quickly gaining fame for another skill.
Marc Mondavi is using his skills at dowsing, or "water witching" to help locate water in the drought-parched state.
"I charge $500, and there's no guarantees, although I'm more than 95-percent successful," Mondavi says.
Not everyone is convinced.
"We have tested dowsers. Through the years, we've tested many dowsers. None of them have been successful in a scientifically controlled test," says James Underdown of the Center for Inquiry Los Angeles.
He believes there's another explanation.
"There's something called the ideomotor effect which says that the unconscious mind can effect the muscles and move muscles without one being conscious of it," Underdown explains.
Underdown's group is offering a $100,000 challenge to anyone who can prove this version of paranormal ability. The test could happen if both sides agree to the rules of the game.