You’re more likely to be (unintentionally) plagiarised by someone who is the same sex as you

Look at some of the most high-profile plagiarism scandals, such as Joe Biden's supposed borrowing from Neil Kinnock, novelist Kaavya Viswanathan's "unintentional" plagiarism of Megan McCafferty and Meg Cabot, science writer Jonah Lehrer's lifting words from this blog, and this week, Melania Trump's echoing of phrases used previously by Michelle Obama (though a speech-writer has taken the blame for this).

Notice a pattern?

In each case, the alleged plagiarists copied others of the same sex. This is anecdotal of course and there are exceptions to the rule – for instance Viswanathan is also alleged to have copied from Salman Rushdie. And yet, maybe there is a psychological phenomenon at work here, especially in instances of unintentional plagiarism – known technically as cryptomnesia – where the plagiarist believes at a conscious level that their words are original, not remembering their true provenance.

For a new study in the journal Memory, Timothy Hollins and his colleagues asked dozens of participants to attend the psych lab and, in pairs, to generate words fitting different subject categories such as Articles of Clothing, Fruit, or Four-Footed Animals. Crucially, some participants did this in same-sex pairs and others in opposite-sex pairs. A week later the participants were recalled to the lab where some of them had to recall just the ideas they'd produced, some had to recall just their partner's ideas, while others attempted to recall both their own and their partner's ideas at the same time under two separate lists.

When asked to recall just their own ideas, or just their partner's, participants were more likely to make errors when their partner was the same sex as them – that is, mistakenly claiming their partner's ideas as their own, or more commonly, their own ideas as their partner's. Presumably having a partner of the same sex made it easier to confuse in memory whose ideas were whose. However, this effect of partner similarity was not present for those participants who were asked to recall separate lists of their own and their partner's ideas at the same time, showing that the confusing effect of partner similarity on memory was surmountable when given a more explicit prompt to make the distinction.

In further, similar experiments with more participants, the researchers looked to see what effect it made at the recall stage whether a participant's partner was present or not. This time, the results showed that participants were more likely to mistakenly recall their partner's memories as their own when their partner was absent, but again only when asked to recall just their own memories, not when asked to list separately their own and their partner's memories. Presumably the presence of a partner made it easier (and more important) to remember whose ideas were whose, although this memory aid had no noticeable benefit when participants were prompted more explicitly to distinguish idea ownership through making separate lists.

Admittedly, these interesting studies are far removed from plagiarism in the real world. As the researchers themselves noted: "Real world interactions, unlike our experiments, rarely involve people taking turns to generate solutions in the knowledge that their memory will be tested later. Additionally, our participants may not have been particularly motivated to claim ownership of generation of a category member in the way that they may care about the genesis of an original scientific idea, a business idea, or a creative output."

Nonetheless, the findings highlight an important, basic memory phenomenon that may play out in the real world – it seems we probably are more likely to confuse our ideas with those of another person when we and they are more similar.

Helpfully, there is also a real-world lesson here in the further finding that partner similarity made no difference to memory mistakes when participants were asked to explicitly recall both their own and partner's ideas at the same time.

As the researchers explained: "When we attempt to reconstruct our memories of past conversations, or of conferences we have attended, the best way to avoid social influences on our source errors is to try to simultaneously recall the contributions from both partners, rather than trying to recall just one source. However, in so doing, we should be aware that we are likely to be attributing our ideas to them than claiming their ideas as our own. But then, as children we are taught that giving is better than receiving."

Further reading

Hollins, T., Lange, N., Dennis, I., & Longmore, C. (2016). Social influences on unconscious plagiarism and anti-plagiarism Memory, 24 (7), 884-902 DOI: 10.1080/09658211.2015.1059857