Some of your best ideas are mine: unconscious antiplagiarism Nicholas Lange, Timothy J. Perfect and Ian Dennis

Standard Paradigm Brown & Murphy (1989): – Semantic category examplar generation – Recall after a delay followed by generate-new phase – Higher plagiariasm than intrusion rates – Plagiarism rates above chance Brown, A. S., & Murphy, D. R. (1989). Cryptomnesia: Delineating inadvertent plagiarism. Journal of Experimental Psychology: Learning, Memory, and Cognition, 15(3), 432–442.

Standard Paradigm Generation

Standard Paradigm Plagiarism Recall

Standard Paradigm Generate New

Standard Paradigm Plagiarism Cryptomnesia Macrae, C. N., Bodenhausen, G. V., & Calvini, G. (1999). Contexts of Cryptomnesia. Social Cognition, 17(3), 273–297.

Standard Paradigm

If source misattribution bias is self-serving

47 participants Mixed Model design – Task: recall own, recall partner, recall both (between subjects) – Delay: one day, seven days (within subjects) Extended paradigm and delay

** Delay

Extended paradigm and delay ** Task

Extended paradigm and delay *

Plagiarism rates increase with delay More ideas are given away than plagiarised Effects not as pronounced with joint-source recall

Source misattribution bias is not exclusively self-serving In fact it appears to be more self- defeating Extended paradigm and delay

Background – Macrae, Bodenhausen and Calvini (1999) – Higher rates of plagiarism with female/female vs female/male pairs Extended paradigm and source similarity ♀ ♂ ♀♀ > Macrae, C. N., Bodenhausen, G. V., & Calvini, G. (1999). Contexts of Cryptomnesia. Social Cognition, 17(3), 273–297.

47 participants Mixed Model design – Task: recall own, recall partner, recall both (between subjects) – Source Similarity: high, low (within subjects) – Delay: 1 week Extended paradigm and source similarity

* ns Source Similarity

Extended paradigm and source similarity ** Task

Extended paradigm and source similarity * * * ns similarity task

More ideas are given away than plagiarised Wrong-source error rates increase with high similarity Recall partner task drives similarity effect – vs. Macrae, Bodenhausen & Calvini (forced recall? between vs within factor?) Joint source recall does not show an effect of source similarity Extended paradigm and source similarity

…and unconscious anti-plagiarism -> wrong-source errors / source misattributions Increase with delay and source similarity also with increased typicality of items, increased similarity of items and instruction to output liberally Unconscious plagiarism?

Extended paradigm and delay Generation phase First recall session A B Set of generated examples per category 1d delay Recall Both Recall Own Target in recall Participant used in example Additional 6d delay Recall Partner Second recall session t B AB A B A B AB A B A Recall Partner

Extended paradigm and source similarity Generation phase Recall phase ♀ ♂ Set of female male generated examples per category 7d delay Recall Partner Recall Both Recall Own ♂ ♀ Target in recall Participant used in example t ♀ ♂ ♀ ♂ ♀ ♀ ♂ ♀ ♀

Extended paradigm and delay Single Source Recall

Extended paradigm and delay Recall Both

Extended paradigm and source similarity -Effect of task on: -Correct recall, RO > RP -Wrong-Source Errors, RO < RP -Intrusions, RO < RP -Effect of similarity on: -Correct recall, High < Low -Wrong-Source Errors, High > Low -Intrusion, High = Low

Extended paradigm and source similarity -Effect of task on: -Correct recall, RO > RP -Wrong-Source Errors, RO < RP -Intrusions, RO < RP -Effect of similarity on: -Correct recall, High = Low -Wrong-Source Errors, High = Low -Intrusion, High = Low