The "amazing" colour changing card trick

   I came across this at the Bad Astronomy Blog, and it so perfectly illustrates a point I have been thinking about recently that I had to pass it along.

   One of the things we skeptics harp on a lot is the double blind test.
   A blind test is one in which the subjects being tested have no knowledge of the preferred outcome, or even of the range of possible outcomes of the test they are undertaking. This is important because studies have shown that subjects tend to try and respond to tests in the way they perceive the tester wants them to. If subjects have foreknowledge of what a study is all about, the results can easily be artificially skewed.
   A double blind test is one in which the person administering the test does not know the preferred outcome either. For example, in a medical drug trial, the physician dispensing the medication, or the practitioner administering the dose, do not know whether their patient is receiving the actual medication, or a placebo. You see, studies have also shown that the testers can - often subconsciously - communicate the desired outcome to their subjects. Which, of course, results in the phenomenon described above. The only way to ensure the results of your test are not being affected by subject or experimenter bias is to control for every possible leakage of information.

   The first mistake often made by a woo-woo is the belief that they cannot be fooled. I can't remember which one of the woo-woo trifecta - Dean Radin, Rupert Sheldrake or Gary Schwartz - it was who said it, but one of them claimed that double blind experiments were a good thing for young science students, but unnecessary for experienced researchers who had learned how to avoid bias in theirstudies. (That sound you just heard, the soft susurration just on the edge of being audible? That was the sound of tens of thousands of scientists simultaneously shaking their heads in sad resignation.) Any serious scientist will tell you that being fooled is one of the easiest things to happen. It can happen to you. It can happen to them. It does happen to them, with embarrassing regularity. That's why science is a peer reviewed process, so that other people can point out to you your errors.

   Just how easy it is to fool you is the subject of the following video clip. Dr. Richard Wiseman is a Professor of Psychology, and the head of a research unit at The University of Hertfordshire, in England. As a former professional magician, he has taken a special interest in the psychological phenomena routinely exploited by stage magicians, as well as psychics, astrologers, and alternative medical practitioners, in the plying of their craft. In the video below, he demonstrates just how easy you are to fool.

Tags: skepticism, magic, science, psychology, woo, you are embarrassingly easy to fool