Alcohol and study list repetition were used to manipulate encoding quality to gain insight into the mechanisms underlying false memories. The DRM paradigm (Deese 1959b; Roediger & McDermott 1995) was used to elicit false memories. Participants studied lists of words (veridical items) which were semantically related to a critical non-presented item, which, if erroneously endorsed, served as the measure of false memory. Implicit and explicit tests of memory were used, and remember know judgments were also taken. An anterograde impairment of memory after alcohol was obtained for veridical items using explicit tests, although no effect of alcohol was found using implicit measures. Alcohol reduced false memory levels relative to placebo for material viewed once at encoding. In accordance with previous en1pirical research, repetition was found to increase, decrease or have no effect on false memory levels. The introduction of distinctive pictorial stimuli at encoding resulted in an inverted U -shaped relationship between repetition and false memories, though this effect was confined to remember judgments only. The increase in false memories as a function of repetition was greater in the alcohol group than in the placebo group_ whilst the placebo group was better able to use extended repetitions to reduce false memories. These results are accounted for using the Activation and Monitoring Framework (Gallo & Roediger 2002). It is suggested that reduced levels of false memories under alcohol for material viewed once can be attributed to reduced activation within semantic networks resulting from superficial encoding under alcohol (Craik 1977) and impoverished attentional resources when intoxicated (Steele & Josephs 1988). The selective impairment of recollective traces under alcohol (Duka ('/ al. 2001) may limit the potential for extended repetitions to diminish false memories under alcohol. The role of metacognitive factors in affecting false memory endorsement is also discussed
