Seek and Ye Shall Find: Test Results Are What You Hypothesize They Are

Gershon Ben-Shakhar
Maya Bar-Hillel
Yoram Bilu
Gaby Shefler

Expert clinicians were given batteries of psychodiagnostic test results (Rorshach, TAT, Drow-A-Person, Bender-Gestalt, Wechsler) to analyze. For half, a battery came along with a suggestion that the person suffers from Borderline Personality disorder, and for half - that battery was accompanied by a suggestion that he suffers from Paranoid Personality disorder. In study 1, the suggestion was made indirectly, through a background story that preceded the test results. In study 2, the suggestion was made directly, by the instructions given. The experts saw in the tests what they hypothesized to be there. In particular, the target diagnoses were rated higher when they were hypothesized than when they were not.

November, 1996
Published in: 
Journal of Behavioral Decision Making 11 (1998), 235-249