A recent study has found that a teenager with an exceptionally powerful memory for his own life experiences also experiences an unusually high rate of memories popping into his mind without any effort. The research suggests that this exceptional memory ability might be driven by an increased sensitivity to memory triggers in the environment rather than just a general tendency to daydream. The findings were published in Cortex.
Highly Superior Autobiographical Memory is a rare condition where a person can recall past personal events with extreme accuracy and detail. People with this ability can often remember the exact day of the week, the weather, and personal activities for almost any given date in their past. For years, scientists mostly focused on how well adults with this condition could intentionally search their memories when asked a specific question.
However, the current understanding of memory highlights that remembering is not always a deliberate choice. Often, memories come to us involuntarily, sparked by a passing smell, a word, or an emotion. Recent research has started to explore this spontaneous side of remembering. For instance, a study covered by PsyPost in 2026 demonstrated that this exceptional memory ability can be verified in early adolescence. Building on this, a 2026 case study provided survey-based evidence that a person with this condition experienced a highly elevated rate of involuntary memories popping into their mind.
“People with Highly Superior Autobiographical Memory are remarkably good at retrieving events from their personal past, and their memories are often described as coming to mind very quickly and effortlessly,” said Krystian Barzykowski, a professor at the Institute of Psychology at Jagiellonian University and head of the Applied Memory Research Laboratory in Poland. “Yet most previous research has examined what happens when these individuals are asked to remember, rather than whether memories also enter consciousness spontaneously, without any intention to retrieve them.”
These earlier studies relied primarily on people keeping diaries or answering questionnaires about their own thoughts. The research, led by Barzykowski and his colleagues, aimed to test whether this influx of spontaneous memories holds up under controlled laboratory conditions. The scientists wanted to measure involuntary thoughts objectively in a teenager who reported having this rare memory condition.
“We therefore wanted to know whether exceptional autobiographical memory is also associated with unusually frequent involuntary memories—those everyday moments when something from your past simply ‘pops’ into mind—and, importantly, to measure this experimentally rather than relying only on questionnaires or diaries,” Barzykowski told PsyPost.
The researchers worked with a 16-year-old male from Poland, referred to as KCL, who had contacted them about his unusual memory. He told the scientists that he felt a constant influx of memories in his daily life and could remember events from at least half the days of his life. To verify his abilities, the researchers first gave him a set of standardized memory quizzes.
“I would also emphasize that our participant himself contacted us because he had begun to realize that the way he remembered his life was unusual,” Barzykowski noted. “It is quite possible that some people with unusually strong autobiographical memory do not realize how exceptional their memory is until they begin to reflect on how much of their personal past they can actually retrieve.”
They asked him to recall the exact dates of recent public events and to retrieve verifiable news stories and personal memories from randomly selected calendar dates. For each answer, KCL had to rate how confident he was and whether he felt he was genuinely remembering the event, knowing it as a fact, or just guessing.
His performance was compared against a group of eight typical adults and one matched 16-year-old boy. On a quiz asking for the dates of public events, KCL scored 51 percent, while the comparison group averaged about 20 percent. On a random dates quiz, KCL successfully recalled details for 83 percent of the prompts, far exceeding the comparison group’s average of 29 percent. This confirmed that his abilities were far above average and met the formal criteria for Highly Superior Autobiographical Memory.
“After systematic testing, his performance exceeded established HSAM thresholds on both the Public Dates and Random Dates screening tasks,” Barzykowski said. “This makes the study an interesting example of how an unusual subjective experience can eventually lead to a testable scientific question.”
To test involuntary memories, the researchers used a computer-based vigilance task. KCL and a separate comparison group of 36 young adults watched a continuous stream of horizontal lines on a screen and had to press a button whenever a rare vertical line appeared. The task was designed to be simple but repetitive, allowing the mind a chance to wander.
Throughout this repetitive task, random everyday phrases appeared on the screen as potential memory triggers. At unpredictable moments, the task paused, and the participants were asked to type out exactly what they were thinking about right before the interruption. They also had to rate how focused they were on the task and whether their thoughts were intentional or spontaneous. This method catches thoughts as they happen, reducing the need for people to actively monitor or remember their own daydreams.
The researchers found that KCL’s mind wandered about as often as the people in the comparison group. He also recognized the random phrases at the same rate as the other participants, showing he was paying a normal amount of attention to the screen. However, the content of his wandering mind was remarkably different.
While the comparison group reported that about 39 percent of their wandering thoughts were memories of the past, 87 percent of KCL’s off-task thoughts were involuntary personal memories. This pattern indicates that KCL does not simply have a more distracted or wandering mind in general. Instead, his spontaneous thoughts are heavily biased toward his own past experiences.
“The difference in involuntary remembering was quite striking for a single case,” Barzykowski explained. “Statistically, his frequency of involuntary memories was almost three standard deviations above the comparison-group mean and fell within the extreme upper range.”
“What I found particularly interesting was the selectivity of the effect,” the researcher added. “KCL was not simply having more spontaneous thoughts overall; rather, when his mind moved away from the task, those thoughts were disproportionately memories of his personal past. Even more strikingly, we did not see a corresponding increase in spontaneous thoughts about the future, suggesting that the effect may specifically concern access to stored autobiographical experiences rather than spontaneous cognition in general.”
In additional questionnaires, KCL reported a much higher confidence in his memory abilities than typical people. He scored especially high on an assessment of his episodic memory, which involves recalling specific personal experiences. Yet, he described his actual feeling of remembering, such as the vividness and emotional intensity of his memories, as being quite similar to how the general population experiences memories.
“Another interesting result was that his general subjective phenomenology of remembering was not dramatically unusual,” Barzykowski said. “So HSAM may not necessarily mean that every memory feels fundamentally different; the crucial difference may instead lie in how readily memories become accessible.”
This distinction highlights the difference between how much information a brain stores and how easily it can be retrieved. “One important misconception is that HSAM means having a photographic or infallible memory. It does not,” Barzykowski emphasized. “Our findings concern accessibility—how readily autobiographical information can be retrieved or enter awareness—not perfect accuracy, and previous research shows that people with HSAM can still be susceptible to memory distortions like everyone else.”
As with all research, there are a few things to keep in mind regarding this study. Because KCL lived far from the researchers, all tests were conducted remotely over video calls with screen sharing. While the researchers supervised the sessions closely, remote testing offers less control over the physical environment than an in-person laboratory visit.
Additionally, this research focuses on a single individual. The findings highlight a specific pattern of involuntary memory in one teenager, but it remains to be seen if all people with this rare memory ability experience the same frequency of unprompted memories.
“The other major caveat is that this is one individual, so we cannot assume that every person with HSAM will show the same pattern,” Barzykowski noted. “Our results should therefore be viewed as strong evidence about this particular case and as a basis for hypotheses that now need to be tested across additional people with HSAM.”
The study also relied on the participant’s own descriptions of his thoughts to determine what qualified as a personal memory during the computer task. While this is the standard method for measuring spontaneous thoughts, it still requires a degree of personal judgment. Future studies might combine these thought sampling tasks with physiological measurements, such as eye tracking or brain imaging, to better understand how these memories emerge.
Moving forward, the team hopes to explore what lowers the threshold for these memories to surface. “The next step is to determine whether this pattern generalizes across a larger group of people with HSAM,” Barzykowski said. “In particular, we want to understand why autobiographical memories become so accessible: whether incidental cues activate their memories more strongly, whether the threshold for a memory entering consciousness is lower, and whether heightened sensitivity to internal or external cues contributes to this process.”
The study’s authors see extreme cases like KCL’s as a valuable tool for decoding the basic mechanics of memory. “By studying an extreme case of autobiographical accessibility, we may learn more about why some memories spontaneously enter awareness while countless others remain outside consciousness,” Barzykowski told PsyPost.
“So, if you feel that your memory for your own past is exceptionally good—or exceptionally poor—we would be very interested to hear from you and, where possible, to assess your memory scientifically,” he added.
The study, “Highly Superior Autobiographical Memory (HSAM) in a 16-Year-Old Male: Investigating Involuntary Autobiographical Memory With Questionnaire and Laboratory Methods,” was authored by Krystian Barzykowski, Valerio Santangelo, Lia Kvavilashvili, and Chris J. A. Moulin. This work was supported by the European Union’s Horizon research and innovation programme.
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