“…In agreement with this hypothesis, numerous studies have shown that the DF effect only occurs if intentional retrieval of items is required (Basden & Bas-den, 1996;Basden et al, 1993;Gardiner, Gawlik, & Richardson-Klavehn, 1994;McKinney & Woodward, 2004;Paller, 1990;Paz-Caballero & Menor, 1999). However, other studies have shown that the DF effect can occur in implicit memory tasks (Lehman, McKinley-Pace, Wilson, Slavsky, & Woodson, 1997;MacLeod, 1989;MacLeod & Daniels, 2000;Paller, 1990;Russo & Andrade, 1995). These discrepancies among studies probably arise from methodological differences that lead to differential contamination of implicit memory performance by explicit (recollective) memory processes.…”