Confirmation bias in the Wyman and Vyse experiment

by Kenneth McRitchie

Correlation, Vol. 29(2), July 2014, pp 26-40


Psychologists Alyssa Jayne Wyman and Stuart Vyse designed their replication of Shawn Carlson’s double-blind astrological experiment to resolve the problem that the participants could not identify their own California Psychological Inventory profiles any better than their own astrological profiles, as written by reputable astrologers. To simplify these selfidentification tasks and ascertain the validity of each of these profile types, the authors used the NEO-FFI psychological self-test versus computer-generated astrological profiles. No astrologers participated. The authors claimed that their test subjects could identify their NEO-FFI profiles at a significant rate but not the astrological profiles. However, a scrutiny of the experimental methodology shows evidence that the claimed findings were due to biases and inefficiencies introduced, perhaps unintentionally, by the authors. The authors’ selective sampling of student subjects, their use and modification of computer-generated astrological profiles, their requirement of a signed astrological knowledge and beliefs questionnaire, the institutionalized bias of their college, and the authority that the authors held over the students all provided opportunities that the authors used to circumvent the double-blind test protocols and sway the results to confirm their own biased beliefs.