A new study shows that employing certain techniques—known as “mental time travel”—can improve recall of that memory. One of the many dreams of sci-fi writers and enthusiasts is the idea of time travel. The study, published in the journal Proceedings of the National Academy of Sciences (PNAS) , wanted to test whether mental time travel could stave off this rapid decline in memory retention. Triggering emotions didn’t improve any noticeable recall, and selective retrieval only delivered 31 percent of the memory. Bur for now, even though mental time travel does allow us to reinforce recent memory, the process of forgetting is always there, waiting once again to start us rolling the rock back up that hill.