Confirmatory bias in the evaluation of personality descriptions: positive test strategies and output interference.

The operation of confirmatory bias in the endorsement of personality descriptions was examined in 4 studies. Unlike M. F. Davies (1997), who provided only inferential evidence for the role of this bias, the present studies provided direct evidence through the experimental manipulation of supporting versus contradictory cognitions. Generating supporting thoughts resulted in greater acceptance whereas generating contradictory thoughts resulted in lower acceptance of personality descriptions. Supporting cognitions were found to be generated before contradictory cognitions in line with a positive test strategy but evidence was also found for an output interference effect (generating one type of thought interfered with the generation of the opposite type) and it was suggested that confirmatory bias is due to the operation of both mechanisms.