A recent study in the Netherlands, published May 2, 2013, in the European Journal of Pscychotraumatology, tested the long-term effect of misinformation on memory.  The study, by Miriam J. J. Lommen, Iris M. Engelhard, and Marcel A. van den Hout, involved as subjects 249 Dutch soldiers deployed to Afghanistan.

The subjects first answered questionnaires two months prior to deployment, and then again two months after deployment; they were given false information in the post-deployment interview about a missile strike on their base.  Follow-up final testing was done seven months later, and 26% of the soldiers -- none of whom had indicated in the two-month post-deployment interview that they had experienced such an event -- indicated that they had experienced the event while deployed.

The authors recounted several earlier studies which showed that, among other things, “memory is malleable.”  For example, a 1974 study demonstrated that the memories of test subjects recalling a film of a car accident were affected by questioners using the words “smash” and “hit.”  Those subjects asked to describe the accident where the cars “smashed” into each other provided higher estimates of speeds of the vehicles and were more likely to recall having seen broken glass, although there was none, than were the subjects being asked to describe the accident where the cars “hit” each other.   In another study, from 1996, participants were asked to describe details about a highly-publicized airplane crash occurring four years earlier.  There was video of the aftermath of the crash, but no video existed of the actual crash.  More than half of the participants recalled having seen video of the crash.

The authors described three factors involved in the creation of such false memories, or “misinformation effect:” 1) “the new information needs to be perceived as plausible;” 2) “the new information should be visualized, vivid images with great sensory and perceptual details are more prone to be (falsely) labelled (sic) as memories for actual events;” and 3) “a source memory error should occur.  This concerns the attribution of the memory’s origin to an incorrect source (e.g., to a personal experience, rather than other people, television, or a newspaper.)"

Sources:  “When Trick Questions Become False Memories,” blogs.discovermagazine.com, June 2, 2013: http://blogs.discovermagazine.com/neuroskeptic/?p=4008#.Ua9enZyCXTo; Abstract: http://www.eurojnlofpsychotraumatol.net/index.php/ejpt/article/view/19864

by Neil Leithauser
Associate Editor

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