Take six people and give them all a list of words to commit to memory individually. Next, have three of those people work as a group to recall as many words as they can. Have the other three people try to recall the words individually, without communicating with one another. As you might expect, three heads are better than one, and the collaborative group will typically be able to recall more words than any one person working alone. However, three against one is hardly a fair competition, so what if we evened the playing field a bit?

Instead of thinking of our six memory test enthusiasts as one trio and three individuals, we could think of them as comprising two groups of three – one collaborative group and one nominal group. The collaborative group produced one list of recalled words together, so that’s straightforward. However, we could also create a single list of recalled words for the other three individuals by combining the three individual lists and omitting any duplicate responses (e.g., if one person correctly recalled the words dog and cat, another recalled the words dog and house, and the third recalled house and cat, then we have a list of three recalled words – dog, cat, and house). This effectively makes them a nominal group (i.e., a group in name only). Now, the question is which group will have correctly recalled more information: the one that collaborated or the one that didn’t?

It may seem surprising, but research on memory suggests that the nominal group is likely to perform better than the collaborative group (Rajaram and Pereira-Pasarin 2010). There’s actually something about the process of collaboration that inhibits our individual ability to recall information that we had previously encoded into our memories. This phenomenon, which is aptly named collaborative inhibition, is thought to be due to the other group members disrupting our individual retrieval strategy.

Essentially, when we encode information into memory, we organize it in a particular way, and when we retrieve it, that method of organization helps us recall it. However, we each have different ways to organize the same set of information, and when we collaborate, other people disrupt our retrieval process (Marion and Thorley 2016). You could think of it like having someone interrupt you while you are telling a story, causing you to lose your train of thought.

It’s not all bad news, though. Because groups remember more than individuals, collaborating at the time of recall can help individual group members remember information that they wouldn’t have remembered on their own. This is likely why team-based testing doesn’t show direct benefits for memory above and beyond what is shown for individual testing. It’s a tradeoff.

To get the most overall benefit out of collaborative testing, research on collaborative inhibition suggests that you should adopt one of two strategies (Blumen and Rajaram 2008). First, because collaboration can disrupt retrieval of individual memories, you can give students a chance to consolidate their individual memories prior to collaborating by having them engage in individual retrieval (this is the typical setup for collaborative testing: an individual test, followed by a collaborative test). Second, you could have them engage in multiple collaborative recall sessions. This strategy does lead to retrieval disruption of the original memory, but the repetition of the collaborative recall helps to consolidate an organized memory based on the group’s recall attempts.


Blumen, Helena M., and Suparna Rajaram. 2008. “Influence of Re-exposure and Retrieval Disruption during Group Collaboration on Later Individual Recall.” Memory 16, no. 3: 231–233. https://doi.org/10.1080/09658210701804495.

Marion, Stephanie B., and Craig Thorley. 2016. “A Meta-analytic Review of Collaborative Inhibition and Postcollaborative Memory: Testing the Predictions of the Retrieval Strategy Disruption Hypothesis.” Psychological Bulletin 142, no. 11: 1141–1164. http://doi.org/10.1037/bul0000071.

Rajaram, Suparna. 2011. “Collaboration Both Hurts and Helps Memory: A Cognitive Perspective.” Current Directions in Psychological Science 20, no. 2: 76–81. https://doi.org/10.1177/0963721411403251.

Rajaram, Suparna, and Luciane P. Pereira-Pasarin. 2010. “Collaborative Memory: Cognitive Research and Theory.” Perspectives on Psychological Science 5, no. 6: 649–63. https://doi.org/10.1177/1745691610388763.

David Buck, associate professor of psychology, is the 2020-2022 Center for Engaged Learning Scholar. Dr. Buck’s CEL Scholar project focuses on collaborative projects and assignments as a high-impact practice.

Icons in featured image from the Noun Project. Collaboration by popcornarts; memory by iconfield.

How to cite this post:

Buck, David. (2021, February 3). When Does Collaboration Hurt Memory? [Blog Post]. Retrieved from https://www.centerforengagedlearning.org/when-does-collaboration-hurt-memory