Single and multiple test repetition priming in implicit memory

Using a picture naming task, we compared the magnitude of repetition priming after one prior study episode (single test priming) versus multiple prior study presentations (multiple test priming). Pictures were repeated either one, two, or three times, and the interval between tests was either several minutes (blocked test) or one week (spaced test). Priming increased with additional prior presentations (beyond one) in the multiple test format. In addition, single test priming decreased within one hour after initial exposure, with little change from one hour to two weeks. Priming was unaffected by a simultaneous recognition task, suggesting that picture naming is an implicit task relatively immune from explicit memory contamination.