When people use their computer or smartphone to store information, they may not be able to detect if that information has been manipulated when they retrieve it later, according to researchers from the University of Waterloo.
“In our study, individuals could rely on an external store when trying to remember some material and manipulations of that store often went undetected,” said Evan Risko, lead author of the study and a professor of psychology.
For the study, participants performed a series of memory tasks where they were required to use a file on a computer to store and later recall a list of words that the researchers presented to them. This computer file functioned as the participant’s external memory store similar to how people might store information they want to remember on a smartphone. For the first three trials, the list the participants stored on the computer was untouched. This allowed participants to develop trust in their external memory store.
On the last trial, researchers secretly inserted a new word into the computer file before the information was retrieved. They then used a variety of measures to determine whether participants noticed the added word or not.
The results showed that people rarely noticed the manipulation of the computer file. In fact, they were often highly confident that items inserted into their external memory had been part of their original list.
In addition, in a later test of their memory without the use of their computer file, participants often reported having been presented with the word that had been inserted into their computer file. Thus, the manipulation of their external memory store had led to the formation of false memory for that information. "Our study showed that exposure to these manipulated external stores led many individuals to form memories for that information.”
While offloading to-be-remembered information to a device has become a common practice in today’s busy digital world, the study highlights one potential risk of relying on this tactic.
“The opportunity to supplement our memory by offloading to more stable external stores has many benefits, but, at the same time, we need to have our eyes open to potential risks associated with this form of remembering,” Risko said. “Understanding these risks will help us reap the most value from our distributed memory systems.”
The study, “Offloading Memory Leaves Us Vulnerable to Memory Manipulation,” appeared in Cognition. Coauthors include Megan Kelly, Payal Patel, and Connor Gaspar.