Unconscious plagiarism occurs when individuals claim previously experienced ideas as their own. Using an adaptation of Brown and Murphy's (1989) three-stage paradigm, participant elaboration was investigated using the Alternate Uses Test at generation. Following generation, ideas were imagined and rated (imagery-elaboration), improved in three ways (generative-elaboration), improved by another participant and then imagined and rated (rich imagery-elaboration) or not re-presented. A week later, participants recalled their original ideas and generated new ideas. Relative to control, elaborating or imagining an idea previously generated by someone else improved recall and reduced plagiarism in the generate-new task. However, in the recall-own task, generative-elaboration alone led to high levels of plagiarism in the recall-own task. Consequently, it is the generative nature of the elaboration performed on an idea that influences later idea appropriation. Copyright © 2006 John Wiley & Sons, Ltd.