Illusory correlation as an obstacle to the use of valid psychodiagnostic signs.

Practicing psychodiagnosticians (N = 32), when surveyed, failed to report observing Wheeler-Rorschach Signs 7 and 8 as accompanying male homosexuality although research evidence indicates that these are valid. They instead reported observing Wheeler Signs 4, 5, 16, 19, and 20, which research literature indicates are invalid. These signs were found to have much stronger rated, verbal associative connections to male homosexuality than the unpopular valid signs. 693 undergraduates (divided among 13 conditions) viewed 30 Rorschach cards on each of which was arbitrarily designated a patient's response and his 2 symptoms. The Ss "rediscovered" the same invalid Rorschach content signs of homosexuality as the clinicians reported, although these relationships were absent in the experimental materials. They did so regardless of the degree to which the clinically valid signs were valid in the contrived task materials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)