Astrologer meets Skeptic |
At our January Mensa Regional Gathering, we ran a simple but revealing test of astrological prediction. Our astrologer, who will remain anonymous, claimed to be able to identify a person's astrological sign based on a half dozen simple questions. Specifically he would guess (his word) three of the twelve birth signs possible for each participant. He further claimed that his success rate was 75% that one of the three signs would be correct. He claimed to have spent decades in studying astrology, and that he had a strong background in science.
As the skeptic, I simply required a demonstration. Seventeen of the audience participated. The result was four correct "guesses". This was in good agreement with the 1 in 4 expected by chance, but far from the dozen or so to be expected for 75% success. The probability of such a disappointing result is astronomical.
Additional data were compiled previously by the Phoenix Skeptics with 2 correct out of 8, again the chance expectation. Further data were compiled and documented using six additional informal predictions for other participants. One of these six was predicted correctly.
The total score was 7 out of 31, a bit under the 25% expected by chance. I offered a $1,000 prize to anyone who can demonstrate the claimed 75% performance under controlled conditions at an appropriate statistical confidence level. My offer still stands. I do commend our astrologer on his having agreed to be tested.
You won't read this report in the Annals of Parapsychology Research, and that's a problem. Who reports "We ran all these tests on astrology and it didn't work"? There is a very strong suspicion of selectivity in reporting of pseudo-science. If you run lots of tests, and for a variety of reasons or excuses exclude reporting the negative results, you can come to wrong conclusions. This is not scientific. More importantly, these claims can be scientifically tested, often easily. Unfortunately those endless anecdotal reports are considered more entertaining - at least by their purveyors.
I hope to see some of you at Glenn Case's new Parapsychology SIG starting in March: especially if you have some special ability to collect my $1,000. And if cash is crass and destroys your talents, we can always donate it to a charity of your choice.