Scientists in France have documented the case of a teenager with extraordinary autobiographical memory. She can vividly reexperience past events and imagine future ones in detail, highlighting a rare form of mental time travel and emotional memory organization.

Remembering past events in minute detail, revisiting them methodically, and reliving past emotions—this is the peculiarity of people with an exceptional memory of their own lives, known as autobiographical hypermnesia, or hyperthymesia. This fascinating condition remains poorly understood, and each new case contributes to our understanding.

In an article in Neurocase, researchers from Paris Brain Institute and the Memory, Brain, and Cognition Laboratory describe the extraordinary mental life of a 17-year-old girl.

Autobiographical memory refers to our ability to remember experiences that have shaped our lives since childhood. It consists of emotional and sensory memories of places, moments, and people, as well as a set of factual information—such as names and dates—that allows us to orient ourselves when we try to recall an episode from the past.

Several studies have indicated that forgotten memories may not be as irretrievable as once thought. Memory appears to be closely tied to the context in which it was encoded. Consequently, remembering smells, sounds and other environmental cues, as well as any feelings experienced during the time the memory was formed can help to recall the memory. However, these memory studies have not sufficiently determined how this kind of contextual memory recall is forgotten after recall.

As most people are aware, retrieving a memory normally becomes more and more difficult as time goes on, but the rate of forgetting actually declines over time in a nonlinear manner due to ongoing memory consolidation. In other words, humans will forget an event at a faster rate within the first few days or weeks, and then the forgetting levels off somewhat and less of the memory is lost over longer time periods.

In a new study, published in the Proceedings of the National Academy of Sciences, a group of German scientists sought to determine if retrieving memories with “mental time travel” can restore the retrieval and forgetting rate to how they were shortly after encoding. To do this, they recruited 1,216 participants to undergo two different memory experiments.