We describe an Introduction to Psychology (IP) demonstration of water dowsing and ideomotor action designed to enhance students' critical thinking. An instructor demonstrated that metal rods crossed over an uncovered cup containing water but not one containing sugar. Student volunteers using the rods also saw them cross over the cup containing water, even after we covered the cup and surreptitiously replaced it with the cup containing sugar (illustrating ideomotor action). Five days later, students who saw the demonstration were (a) less convinced of the validity of dowsing and facilitated communication after reading anecdotal evidence and (b) more likely to suggest ideomotor action as an explanation for several ideomotor-related phenomena compared to students in the control sections of IP.