Proactive and Retroactive Priming in Serial Target Detection

Four experiments were concerned with priming effects that occur when participants attempt to identify each letter in a briefly presented 4-letter display. At each position of the display, 1 alternative (the target) was more probable than 4 alternatives (nontargets). The basic finding, which held true over several manipulations of display characteristics, was that retroactive effects were generally much stronger than proactive effects. These strong retroactive effects contrast with prior findings that (a) proactive effects usually dominate and (b) repetition yields inhibition (repetition blindness). This asymmetry was also noted in an additional experiment in which participants responded to only 1 letter in the array.