When learning, practice doesn’t always make perfect.

UC Irvine neurobiologists Zachariah Reagh and Michael Yassa have found that while repetition enhances the factual content of memories, it can reduce the amount of detail stored with those memories. This means that with repeated recall, nuanced aspects may fade away.

In the study, which appears this month in Learning & Memory, student participants were asked to look at pictures either once or three times. They were then tested on their memories of those images. The researchers found that multiple views increased factual recall but actually hindered subjects’ ability to reject similar “imposter” pictures. This suggests that the details of those memories may have been shaken loose by repetition.

This discovery supports Reagh’s and Yassa’s Competitive Trace Theory — published last year in Frontiers in Behavioral Neuroscience — which posits that the details of a memory become more subjective the more they’re recalled and can compete with bits of other similar memories. The scientists hypothesize that this may even lead to false memories, akin to a brain version of the telephone game.

Yassa, an assistant professor of neurobiology & behavior, said that these findings do not discredit the practice of repetitive learning. However, he noted, pure repetition alone has limitations. For a more enriching and lasting learning experience through which nuance and detail are readily recalled, other memory techniques should be used to complement repetition.

Yassa and Reagh, a graduate student researcher in Yassa’s lab, are members of UC Irvine’s Institute for Memory Impairments and Neurological Disorders and Center for the Neurobiology of Learning & Memory.

The study was conducted at Johns Hopkins University before the team relocated to UC Irvine in January. The work was supported by the National Institute on Aging (grants P50-AG05146 and R01-AG034613) and the National Science Foundation Division of Graduate Education (grant DGE-1232825).