Two Bs or Not Two Bs? A Signal Detection Theory Analysis of Repetition Blindness in a Counting Task

Notes that stimulus repetition usually benefits performance. A notable exception is repetition blindness (RB), in which subjects (Ss) fail to report a repeated stimulus in a rapid serial visual presentation. Theories differ in attributing RB to either perceptual encoding or memory retrieval and to impaired discrimination vs response bias. In the present study, Ss judged whether 1 or 2 letters were imbedded in sequences of digits. Unlike previous studies, false guesses of 2 unrepeated letters were distinguished from false guesses of 2 repeated letters. When repeated- and unrepeated-letter trials were randomly intermixed (Exp 1, with 60 college student Ss), RB was entirely attributable to response bias. However, when they were separately blocked (Exps 2 and 3, with 38 and 26 college students, respectively), RB was manifested in discriminability. The results support perceptual-encoding accounts of RB but indicate that effects on discriminability depend on Ss' processing strategies