Teenager with hyperthymesia exhibits extraordinary mental time travel abilities

A new case study describes a teenage girl with an extraordinary ability to recall personal memories in vivid detail and mentally revisit specific moments in her life at will. Her experiences reflect a rare condition known as hyperthymesia, or highly superior autobiographical memory. The report, published in Neurocase, highlights her unusual capacity for mental time travel—not only into the past, but also into imagined futures—offering researchers new insight into how autobiographical memory may be organized and accessed in the brain.

Autobiographical memory refers to the ability to recall personal experiences and events situated in time and space. It includes both general life knowledge and episodic details that help people construct a sense of self and continuity over time. Some individuals possess an exceptionally rich form of this memory. Known as hyperthymesia or autobiographical hypermnesia, this condition is marked by an unusual ability to recall past personal events with extraordinary clarity and accuracy.

People with this ability tend to describe their memories as highly vivid, emotionally intense, and embedded in a strong sense of personal re-experiencing. This subjective feeling—often referred to as autonoetic consciousness—is closely linked to what scientists call mental time travel, or the capacity to mentally revisit the past and pre-experience the future.

Although a handful of such cases have been documented in the literature, hyperthymesia remains rare and poorly understood. In this new case report, researchers Valentina La Corte, Pascale Piolino, and Laurent Cohen—based at institutions including the Paris Brain Institute and the Université Paris Cité—explore how one teenage girl’s memory system operates, and how it may contribute to future research on personal memory and cognition.

The subject of the study, referred to as TL, was a 17-year-old high school student in France when she came to the researchers’ attention. She had long known her memory was different. As a child, she would casually mention her ability to mentally revisit past events to check for details, only to be accused of lying by her peers. Eventually, she disclosed this ability to her family at age 16.

TL’s recollections were not merely accurate—they were structured. She described a highly organized internal world where memories were stored in a large, rectangular “white room” with a low ceiling. Within this mental space, personal memories were arranged thematically. Sections were dedicated to family life, vacations, friends, and even her collection of soft toys. Each toy had its own memory tag, including information about when and from whom it was received.

Importantly, these recollections were not purely factual. They carried emotional weight and vivid perceptual details. TL could mentally relive events from both her original perspective and from an outside observer’s view. She described, for instance, her first day of school in striking detail: what she wore, the weather, and the precise visual memory of her mother watching her through the fence. These experiences were accompanied by a strong sense of re-experiencing.

In contrast to this rich “white room” of personal events, TL referred to her semantic and academic knowledge as “black memory.” This separate system lacked emotional content and spatial organization, and it was acquired through deliberate effort rather than spontaneous recollection.

Beyond memory storage, TL described three additional rooms in her internal world, each associated with specific emotional functions. A cold “pack ice” room helped her cool down when angry. A “problems room” was empty but served as a space for pacing and thinking. A more uncomfortable “military room,” associated with her father’s absence due to military service, was linked to guilt. These features suggest a broader internal architecture shaped by emotional needs and reflective processes, not just memory content.

To objectively assess TL’s autobiographical memory, the researchers administered two standardized tasks. The first, the TEMPau task, evaluates how people recall personal events from different life stages. TL was assessed only for childhood and adolescence, given her age. Her scores were well above the norm. She produced highly specific, richly detailed memories and consistently reported a sense of “remembering” rather than simply “knowing” facts. She also demonstrated an ability to shift between field and observer perspectives when describing events.

The second task, the TEAAM, measured her ability to recall or imagine brief, detailed episodes from both the past and the future. TL again performed at the top of the expected range. Her imagined future events were not only plausible and contextually rich, but also carried a strong feeling of “pre-experience”—a subjective sensation akin to remembering, but applied to anticipated personal events.

The researchers noted that TL’s performance declined slightly when imagining more distant future events. This tendency aligns with what is typically seen in the general population: the further away an event is in time, the less vivid and detailed it tends to be. Still, TL’s ability to mentally travel through time—to revisit the past and pre-live the future—was striking.

Although TL’s case provides compelling insights, it is important to acknowledge the limits of case studies in general. Single cases do not allow for broad generalizations. There are no control groups for comparison, and findings cannot speak to prevalence or typical development.

In TL’s case, the researchers did not use some of the traditional diagnostic tools for hyperthymesia, such as verifying public event recall or testing calendar accuracy over many years. Her superior memory was based on self-report, corroborated by performance on specific tasks, but not benchmarked against the same criteria used in some earlier studies.

There are also limits to verifying the accuracy of detailed childhood memories. Some events may be reconstructed, influenced by photos, family stories, or even dreams, which TL herself acknowledged as occasional sources of memory content.

Despite these constraints, case reports like this one remain an important tool in the scientific study of the mind. When researchers encounter rare or unusual cognitive profiles, documenting them in detail can generate new hypotheses, refine existing theories, and identify directions for future research.

In TL’s case, her vivid and structured autobiographical memory, along with her conscious and emotionally guided use of mental time travel, points to a potentially unique form of memory organization. Unlike previous cases where hyperthymesia seemed involuntary or overwhelming, TL appeared to have some degree of control over how she accessed and navigated her memories. Her experiences also invite questions about the role of emotion, spatial imagery, and subjective perspective in the construction of memory.

Additionally, her use of imagined rooms tied to emotional regulation adds a novel dimension to how memory might interface with other cognitive processes. It hints at the possibility that some individuals may develop internal mechanisms to manage the emotional weight of their memories or structure them in ways that aid retrieval.

“It is difficult to generalize findings about hyperthymesia, since they rely on only a few cases. Does ageing affect the memories of these individuals? Do their mental time-travel abilities depend on age? Can they learn to control the accumulation of memories? We have many questions, and everything remains to be discovered. An exciting avenue of research lies ahead,” concludes La Corte.

The case report, “Autobiographical hypermnesia as a particular form of mental time travel,” was published August 1, 2025.