DMT, Highly Superior Autobiographical Memory (HSAM), and the Brain That Remembers Everything Until It Forgets Who You Are
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If you belong to Generation X, as I do, you probably remember the television sitcom Taxi, one of the great comedies of the late 1970s and early 1980s. It featured an extraordinary collection of characters working out of a New York City taxi garage, including Danny DeVito as the wonderfully obnoxious Louie De Palma, Christopher Lloyd as the perpetually bewildered Reverend Jim Ignatowski, Tony Danza as Tony Banta, and Andy Kaufman as Latka Gravas. The show ran from 1978 to 1983, won eighteen Emmy Awards, and somehow managed to turn the miserable working lives of cab drivers into some of the funniest television of its generation. Among that unforgettable cast was a beautiful redhead named Marilu Henner, who played Elaine Nardo.
What I did not know back then was that Henner possessed a memory so extraordinary that scientists would eventually study her brain to understand how it was possible. While the rest of us were watching Taxi, laughing at Reverend Jim’s latest encounter with ordinary reality, Henner was accumulating an autobiographical record of her life that she would still be able to retrieve decades later. She could remember the dates of events, conversations, activities, and details from ordinary days that most people would have forgotten before the next episode aired. Apparently, somebody in that television garage was paying considerably more attention to the passage of time than the rest of us.
On December 19, 2010, CBS broadcast a remarkable 60 Minutes investigation hosted by Lesley Stahl. The subject was a rare condition called Highly Superior Autobiographical Memory, abbreviated HSAM and also known as hyperthymesia. Henner was among the handful of people then identified with the ability, and the program introduced millions of viewers to individuals who could remember astonishing details from nearly every day of their adult lives.
Henner’s appearance was especially entertaining because she and Lesley Stahl had been friends for years. Imagine interviewing someone who can remember the dates, locations, conversations, and meals from your shared history while you struggle to remember which restaurant served the salmon. For most of us, that would be an uncomfortable afternoon. I can imagine entire marriages being placed in immediate jeopardy if one partner suddenly acquired an infallible historical record of every disagreement while the other continued relying on the traditional defense of having absolutely no recollection of the incident.
Henner described her recollections as something resembling selected scenes on a DVD. Give her a year, and the chronology of that year becomes available to her, with individual days accessible within it. In another interview, she recalled learning that she had won her role on Taxi on Sunday, June 4, 1978, at a party celebrating the premiere of Grease. She also recalled the dates of the show’s first rehearsal and first filming. I have trouble remembering where I put my glasses five minutes ago, so I find the ability to retrieve the exact date of a professional event from almost fifty years ago rather impressive.
But Henner was not the person who first brought this condition to scientific attention. That distinction belongs to a woman named Jill Price, whose remarkable memory had become something considerably more complicated than a party trick. In June 2000, Jill Price contacted neuroscientist James McGaugh at the University of California, Irvine. She was thirty-four years old and wanted help understanding something that had troubled her for much of her life. Unlike most people who approach memory researchers because they are forgetting too much, Price had the opposite problem. Her memory seemed unwilling to let much of her personal history go.
She explained that she could take dates going back to childhood and describe what happened on those days, including ordinary personal experiences and public events. She did not have to consult calendars or spend hours reconstructing her answers. The memories arrived automatically, sometimes whether she wanted them or not.
For Price, this was not simply an entertaining talent. Recollections of painful experiences could return with an intensity that made the past difficult to escape. While most of us benefit from the gradual fading of old humiliations, arguments, losses, and romantic disasters, Price experienced a personal history that was unusually reluctant to fade into the background. There is something deeply human about wanting to forget. We occasionally need a little distance from our own biographies. I suspect that if everyone retained perfect access to every foolish thing they had ever said, civilization would quickly develop a thriving industry devoted to voluntary amnesia.
McGaugh and his colleagues began investigating Price’s remarkable ability. They tested her recollections against calendars, public records, and diaries she had maintained over many years. What emerged was sufficiently unusual that Elizabeth Parker, Larry Cahill, and McGaugh published a scientific paper in 2006 titled A Case of Unusual Autobiographical Remembering. They initially identified Price by the initials AJ and introduced the term hyperthymestic syndrome.
The condition was not the same as the extraordinary memorization techniques performed by trained memory champions. Price was not demonstrating an ability to memorize thousands of random digits or entire decks of playing cards through elaborate mnemonic methods. Her unusual talent involved remembering her own life, and that distinction turned out to be fundamental. As researchers identified more people with similar abilities, the condition became known as Highly Superior Autobiographical Memory. These individuals could retrieve details of ordinary experiences with extraordinary accuracy, often organized around dates and personal chronology. Yet their performance on conventional memory tasks was not necessarily exceptional.
That raises a fascinating question about why the brain would preserve such extensive access to autobiographical history without providing equally extraordinary recall for every other kind of information. The answer remains incomplete, but it suggests that the architecture of remembering may matter as much as the amount of information retained. The 60 Minutes investigation helped bring this obscure scientific phenomenon into public view. When the original program aired in 2010, researchers had identified only six people with the ability. By the time CBS returned to the subject in January 2014, dozens more had come forward, and the number identified for scientific investigation had grown beyond fifty.
The follow-up featured people including Louise Owen, Bob Petrella, and a young boy named Jake Hausler. Seeing individuals from different backgrounds recognize the same unusual ability helped establish that scientists were dealing with something more interesting than one remarkable person’s memory. Here was a natural variation in human cognitive functioning that demanded explanation.
In 2026, researchers led by Fabrizio Parente published a study in NeuroImage examining the brain activity of twelve individuals with HSAM and thirty-one matched controls. They found unusually strong and temporally stable functional connectivity among regions involved in autobiographical memory, personal schemas, and self-referential processing. These included the hippocampus, temporal pole, and ventromedial prefrontal cortex, regions that interact with the broader neurological system known as the default mode network.
The researchers suggested that this enhanced network stability might contribute to continuing memory replay and consolidation. They did not discover a permanent neurological recording of every conscious moment, and they did not establish that stable connectivity alone causes HSAM. They identified an unusual relationship in the functional organization of regions involved in personal memory. The default mode network, commonly abbreviated DMN, is particularly interesting because it participates in activities we rarely associate with simply being conscious. When we remember our childhoods, imagine possible futures, reflect upon ourselves, or construct narratives about our lives, components of this network frequently participate.
It is involved when we mentally revisit an argument from twenty years ago and finally invent the perfect response, generally while taking a shower and with absolutely no possibility of delivering it to the intended recipient. The human brain is remarkably dedicated to winning arguments long after everybody else has forgotten they occurred. But these abilities are far more significant than replaying old grievances. They help us construct the continuing story of who we are.
Think about the difference between knowing that a hurricane struck Florida in a particular year and remembering standing outside as the storm approached. The first is historical knowledge. The second belongs to an autobiographical perspective. It connects an event to your own body, your location, your emotions, and your recognition that the person experiencing it was you. Memory allows us to reach backward into our personal histories while remaining conscious in the present. We can recall being children while simultaneously understanding that we are no longer those children. We can remember people who have died, places that no longer exist, and experiences that permanently changed us.
The original events are over, but their representations can remain active within the organism that experienced them. For people with HSAM, access to those representations is extraordinarily extensive. This made me wonder whether consciousness and autobiographical identity are more distinct than our ordinary experience suggests. Perhaps the brain does not simply contain memories but continually organizes them around a continuing model of the individual who experienced them. And then I encountered another body of research that appeared, at least conceptually, to approach that same organization from a very different direction.
Dimethyltryptamine, better known as DMT, is a powerful psychedelic compound capable of producing extraordinarily intense alterations of perception, thought, emotion, and personal identity. People who have experienced its effects sometimes describe elaborate geometric environments, encounters with seemingly autonomous beings, profound changes in their perception of time, or a temporary disappearance of the familiar boundary between themselves and the surrounding world.
Some return from these experiences believing they have encountered realities ordinarily inaccessible to human consciousness. Others describe an experience so unlike everyday life that they struggle to explain it afterward. I find these accounts fascinating, although I would hesitate before accepting travel brochures from someone who claims to have visited another dimension while lying on a couch. Human beings have an extraordinary talent for mistaking the intensity of an experience for proof of its external interpretation.
What interests me is not whether DMT opens a portal to another universe. It is what the substance reveals about the human brain’s ability to reorganize ordinary conscious experience. In 2023, researchers led by Christopher Timmermann published a study combining electroencephalography and functional magnetic resonance imaging to investigate the effects of DMT on human brain activity. The researchers observed reduced within-network connectivity integrity in several canonical resting-state networks, including the default mode network, alongside increased global connectivity and changes in network segregation.
The brain was not simply becoming inactive. Established patterns of organization were changing, with some ordinarily distinct networks becoming less segregated while other forms of interaction increased. A particularly intriguing effect associated with powerful psychedelic experiences is ego dissolution, in which the familiar sense of being a separate individual can temporarily weaken or disappear.
Under ordinary conditions, we experience the world from a relatively stable personal perspective. There is a body, a history, a name, a collection of memories, and a continuing sense that the experiences occurring right now belong to the same individual who experienced yesterday. Under certain psychedelic conditions, aspects of that ordinary organization can become profoundly altered. People sometimes report that the distinction between themselves and their surroundings has disappeared, or that personal identity has temporarily lost its usual importance.
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What interests me is how these profound changes in the ordinary sense of self can occur while the person continues reporting vivid conscious experiences. The familiar autobiographical reference point can become less prominent without experience itself necessarily disappearing. Here is where the High-end Pondering begins.
In HSAM, researchers observe individuals with exceptional access to personal history, accompanied by evidence of unusually stable connectivity among certain regions involved in autobiographical memory and self-reference. Under DMT and related psychedelic states, researchers observe alterations in the ordinary experience of personal identity, accompanied by changes in the integrity, connectivity, and segregation of large-scale brain networks. Could these represent different configurations of the organization through which the brain maintains our autobiographical identities?
I am not proposing that scientists have discovered a single dial with hyperthymesia at one end and DMT at the other. The studies involve different populations, different experimental conditions, and different neurological measurements. Stable resting-state connectivity in HSAM cannot simply be equated with changes measured during an acute psychedelic experience. But the comparison raises a legitimate theoretical possibility. Perhaps the autobiographical self is not a fixed object stored somewhere inside the brain. Perhaps it is an organization continually maintained through relationships among memory, perception, bodily information, expectations, and self-reference.
Under ordinary conditions, that organization allows us to maintain a coherent personal history despite constant biological change. In HSAM, aspects of the organization responsible for autobiographical accessibility may function with unusual stability or effectiveness. Under psychedelic ego dissolution, aspects of the ordinary organization of selfhood may temporarily become less stable, less segregated, or differently integrated.
The conscious organism continues functioning, but its relationship to autobiographical identity can change dramatically. This raises another possibility worth investigating: perhaps memory is not what makes consciousness exist, but one of the processes through which consciousness becomes organized around the experience of being a continuing individual. I keep returning to an analogy from the natural world. A tree records aspects of its history in its growth rings. Every year adds another layer, and those layers preserve physical evidence of earlier conditions. Drought, injury, growth, and environmental change may all leave recognizable marks.
Rock formations preserve records of environments that disappeared millions of years ago. The landscapes themselves are gone, but information about their histories survives in the structures they left behind. Human memory is considerably more complicated. It is reconstructive rather than a perfect historical recording, and even people with HSAM remain susceptible to memory errors. Nevertheless, the brain’s present organization is partly the consequence of experiences that occurred years or decades earlier.
The past is not simply absent from the present. It has helped construct the physical organism that now exists. For someone with HSAM, an extraordinary amount of that personal history remains accessible. A date can serve as a cue that reactivates memories of experiences that occurred decades before. That made me wonder whether past and present might be understood as different temporal representations operating within the same continuing biological host.
I do not mean that 1985 occupies a secret physical dimension somewhere behind the hippocampus, waiting for scientists to discover a tiny doorway. I mean that the present conscious process can incorporate representations of events that occurred decades earlier, including the recognition that the individual who experienced them is the same individual now recalling them. The earlier experience is no longer happening in the external world, but the memory of that experience can participate in present awareness. The tree preserves its history in physical layers. The brain preserves and reconstructs aspects of its history through complex biological relationships that influence what the organism can experience and remember today.
Perhaps the most interesting question is not how many memories the brain can retain, but how those memories become incorporated into the ongoing experience of being someone. DMT approaches that question from another direction. If the ordinary autobiographical framework can temporarily lose its prominence while vivid experience continues, perhaps personal identity is one achievement of consciousness rather than a necessary component of every conscious experience.
We often treat consciousness and personal identity as interchangeable, but neurological and psychological evidence suggests that the relationship is more complicated. People with profound autobiographical memory impairments can remain conscious. They may have difficulty reconstructing their personal histories while continuing to perceive, respond, feel emotions, and experience the immediate world.
People undergoing psychedelic ego dissolution can report extraordinarily vivid experiences despite major alterations in their normal sense of personal identity. And people with HSAM possess unusual access to autobiographical memory without any established evidence that they possess more consciousness than everybody else. These observations suggest that the ability to remember one’s personal history and the existence of conscious experience are not identical capacities.
This distinction connects directly to my work on the Observer Birth Principle. In that research, I explore the idea that consciousness develops through increasingly sophisticated forms of registration, persistence, comparison, memory, and self-reference. A system that can preserve earlier states and compare them with later states possesses a relationship with time that a system without usable memory cannot maintain in the same way.
As biological organization becomes more complex, the observer can eventually become part of its own internal model. The organism does not merely distinguish objects in the external world. It can recognize its own body, retain aspects of its history, anticipate future experiences, and represent itself as a continuing participant in the surrounding environment. Autobiographical memory contributes to the temporal depth of that self-model. HSAM presents an unusual biological example of extraordinary access to that depth. Psychedelic ego dissolution presents an unusual alteration in the organization through which personal identity is ordinarily experienced.
Neither phenomenon solves the Hard Problem of Consciousness, nor is that what I am attempting to do. My interest is in investigating how conscious organization changes, what maintains personal continuity, and what unusual human conditions might reveal about processes we normally take for granted. I am particularly interested in the possibility that the experience of being oneself is not a fixed condition, but something the brain continually maintains.
The comparison between HSAM and psychedelic ego dissolution offers several avenues for scientific investigation. Researchers could examine whether particular measures of network stability predict autobiographical accessibility, whether changes in those networks accompany changes in subjective self-continuity, and whether memory accessibility and the felt boundaries of personal identity can vary independently. A person might possess exceptional autobiographical recall without experiencing an unusually strong sense of personal identity. Another might temporarily experience weakened self-boundaries while retaining vivid conscious awareness.
If these capacities vary independently, their relationships may reveal something important about how the brain organizes conscious life. The relevant comparison would require careful measurements rather than simply declaring HSAM and DMT neurological opposites. Researchers would need to examine the same network properties across comparable experimental conditions and distinguish the effects of memory retrieval from the effects of subjective self-boundary changes.
Nature has a long history of refusing to arrange complicated phenomena into the neat diagrams human beings prepare for it, and I see no reason to assume consciousness will suddenly become cooperative. Still, the investigation is worthwhile because the observations are real. HSAM exists. Psychedelic ego dissolution is a documented subjective phenomenon. Brain-network changes associated with autobiographical memory and psychedelic states have been measured. What remains unknown is whether these observations illuminate a shared organizing principle underlying autobiographical selfhood.
Perhaps the strangest thing about personal identity is how ordinary it feels. I wake up every morning and assume I am the same person who went to sleep the night before. I do not request documentation from my hippocampus. I do not demand that my default mode network provide identification, references, or a sworn statement explaining what happened while I was unconscious. I simply continue being myself.
Yet the machinery responsible for that effortless assumption is astonishingly complicated. Memories are maintained and reconstructed, neural relationships change, experiences accumulate, and enormous portions of our personal history disappear from accessible recollection. Despite all of that, we continue experiencing ourselves as individuals with relatively coherent histories. HSAM reveals that access to those histories can become extraordinary. DMT and related psychedelic experiences reveal that the familiar organization of personal identity can become profoundly altered.
One person may remember the weather from an ordinary Tuesday thirty years ago. Another may temporarily experience a state in which the distinction between the self and the surrounding world becomes difficult to maintain. Somewhere between these phenomena may lie an important clue about how the human brain organizes a lifetime into the experience of being someone. I find that possibility fascinating because it suggests that our ordinary sense of self is not nearly as simple or permanent as it appears. It may be a continuing achievement of biological organization, dependent upon relationships among memory, perception, bodily information, and the passage of time.
We spend our lives assuming that personal identity is something we possess. Perhaps it is more accurate to say that identity is something our brains are continually maintaining, revising, and reconstructing. For most of us, the arrangement works well enough that we rarely notice the machinery behind it. For Marilu Henner, the past remains extraordinarily accessible. For someone undergoing profound psychedelic ego dissolution, the familiar boundaries of the autobiographical self can temporarily become difficult to locate.
And for those of us who grew up watching Taxi, there is something wonderfully ironic about discovering that one of the show’s most memorable performers turned out to be scientifically remarkable for an entirely different reason. Forty years after watching Elaine Nardo navigate the absurdities of a New York taxi garage, I find myself investigating the extraordinary brain of the actress who played her, wondering what it might teach us about memory, time, and consciousness. It is the sort of unexpected connection that makes High-end Pondering worthwhile. And if Marilu Henner ever reads this essay, I suspect she might remember exactly what she was doing the day she first encountered it. I will consider myself fortunate if I remember where I saved the file.
One final thought keeps nagging at me. As researchers race toward artificial intelligence capable of something resembling consciousness, I cannot help wondering whether these two extraordinary phenomena might offer clues they have been overlooking. One reveals a brain capable of maintaining remarkable access to its own history, while the other reveals how profoundly the familiar sense of self can change when the brain’s ordinary organization is disrupted. Somewhere between the preservation of autobiographical identity and its temporary dissolution, there may be something worth understanding about how consciousness organizes itself.
I am not suggesting that either phenomenon contains the secret to building a conscious machine, but I suspect that anyone seriously pursuing that ambition could benefit from getting their arms around both. After all, we are spending billions trying to teach machines how to think, remember, and perhaps one day recognize themselves, while the human brain continues demonstrating abilities we barely understand. It might be worth figuring out what nature has already accomplished before congratulating ourselves on whatever we manage to manufacture.
