Assessing the effectiveness of warnings and the phenomenological characteristics of false memories

The phenomenology of false memories was investigated in three experiments i n which participants heard two experimenters read lists of items that were related to critical nonpresented items. In Experiments 1, following a recog nition memory test, participants rated the phenomenological characteristics of their memories immediately and after a 48-hour delay. False recognition was prevalent and on several dimensions participants rated their true memo ries as more vivid than their false memories. In Experiments 2 and 3, follo wing the study phase, participants were warned about the phenomenological d ifferences between true and false memories and were instructed to use this information to avoid reporting nonpresented items. This type of warning was ineffective at reducing false recall (Experiment 2) and false recognition (Experiment 3) relative to unwarned participants. Importantly, the inabilit y of explicit warnings to impact illusory recollections demonstrates that t he false memories cannot be attributed simply to a criterion shift.