Exploring the role of repetition and sensory elaboration in the imagination inflation effect

Imagination as a cause of memory distortion has generated much recent interest. Researchers have demonstrated that memories for both childhood events and more recent actions are influenced by imagination (Garry, Manning, Loftus, & Sherman, 1996; Goff & Roediger, 1998). Typically, confidence in the occurrence of fictitious events increases after those events have been imagined— a phenomenon called imagination inflation. An increase in source-monitoring errors after repeated imagining has also been used to demonstrate the imagination inflation effect. For example, Goff and Roediger found that participants erroneously remembered performing actions after only imagining those actions. Although imagination inflation has been demonstrated repeatedly (Garry et al., 1996; Goff & Roediger, 1998; Heaps & Nash, 1999; Paddock et al., 1999; Thomas & Loftus, 2002), the debate over the cause of the imagination inflation effect continues. Previous research suggests that imagination inflation can be accounted for by both the source-monitoring framework (Johnson, Hashtroudi, & Lindsay, 1993) and familiarity misattribution theory (Jacoby, Kelley, & Dywan, 1989). However, if familiarity misattribution adequately accounts for imagination inflation by rendering the imagined event more familiar and available (Garry et al., 1996), then imagining itself may not be necessary to achieve the effect. If, however, imagination inflation is driven primarily by the misattribution of sensory and perceptual detail, then imagination would be key to the effect, and the source-monitoring framework would best account for this particular false memory phenomenon. The goal of the present study is to examine whether it is misattribution of discrete or specific memory characteristics, such as sensory detail, or misattribution of more general memory characteristics, such as familiarity, that drives the imagination inflation effect.