When from a long-distant past nothing subsists, after the people are dead, after the things are broken and scattered, still, alone, more fragile, but with more vitality, more unsubstantial, more persistent, more faithful, the smell and taste of things remain poised a long time, like souls, ready to remind us, waiting and hoping for their moment, amid the ruins of all the rest; and bear unfaltering, in the tiny and almost impalpable drop of their essence, the vast structure of recollection.
And once again I had recognized the taste of the crumb of madeleine soaked in her decoction of lime-flowers which my aunt used to give me (although I did not yet know and must long postpone the discovery of why this memory made me so happy), immediately the old gray house upon the street, where her room was, rose up like the scenery of a theater.
— Marcel Proust (1913): À la recherche du temps perdu. In Search of Lost Time (alternative translation: Remembrance of Things Past). Vol I: Swann's Way.

The identity of the self encompasses “what” and “who” elements. The empirical fact that we permanently inhabit a singular, incrementally changing, primate body, more or less answers the “what” question. The intersection of embodiment with the “who” aspect is more slippery.

 

We are mind on the hoof and our innate emotions and particular character dispositions inform our every move. They define us in the broadest of brushstrokes.

We go through life aware of ourselves as unique entities with the power to act. We are predisposed to make sense of our world and our place in it and tend to experience life as discrete characters in a story slowly unfolding in real time.

Memory and imagination are both capable and fallible. We are only human. Our cognitive horizons are finite; we can only take in so much at a time. Existentially our awareness is confined to the fleeting moment, but we rely on recall and we anticipate. As a consequence, the past and the future always seem to be right there with us. The ipse, or narrative self, construes itself as a constantly updated distillation of past and future, rather than a succession of unexamined nows.

Our waking experience is anticipatory.

Dr. Endel Tulving interviewing amnesic patient Kent Cochrane In Cochrane was involved in a motorcycle accident that left him with permanent severe amnesia.  

Dr. Endel Tulving interviewing amnesic patient Kent Cochrane In Cochrane was involved in a motorcycle accident that left him with permanent severe amnesia.  

The outstanding fact about K.C.'s mental make-up is his utter inability to remember any events, circumstances, or situations from his own life. His episodic amnesia covers his whole life, from birth to the present. The only exception is the experiences that, at any time, he has had in the last minute or two… The impairment does not encompass only the past; it also extends to the future. Thus, when asked, he cannot tell the questioner what he is going to do later on that day, or the day after, or at any time in the rest of his life. He cannot imagine his future any more than he can remember his past. This aspect of the syndrome he presents suggests that the sense of time with which autonoetic consciousness works covers not only the past but also the future.

 

Because everyone does it, there is nothing marvelous about it.

If there is hope for a more appropriate assessment of the uniqueness of episodic memory and autonoetic consciousness, it may come through the realization that mental time travel involves awareness not only of what has been but also of what may come. This awareness allows autonoetic creatures to reflect on, worry about, and make plans for their own and their progeny's future in a way that those without this capability possibly could not. Homo sapiens, taking full advantage of its awareness of its continued existence in time, has transformed the natural world into one of culture and civilization that our distant ancestors, let alone members of other species, possibly could not imagine.

It took biological evolution a long time to build a time machine in the brain, and it has managed to do it only once, but the consequences have been enormous: By virtue of their mental control over time, human beings now wield powers on earth that in many ways rival or even exceed those of nature itself. It is difficult to imagine a marvel of nature greater than that.

The first clue is offered by a perceived absence. There is no evidence that any nonhuman animals—including what we might call higher animals—ever think about what we could call subjective time. Animals are as capable as humans have been at the game of producing more of their kind. They have minds, they are conscious of their world, and they rely as much on learning and memory in acquiring the skills needed for survival as we do (Weiskrantz 1985), but they do not seem to have the same kind of ability humans do to travel back in time in their own minds, probably because they do not need to. The clue suggests that one's sense of subjective time is not a biological necessity. If humans have it, it is an evolutionary frill, necessary for mental time travel. No sense of subjective time, no mental time travel.

A second clue is provided by the realization that, when we do travel back in time, our conscious awareness of our experience is different from our ordinary “on-line” awareness of our environment. We seldom confuse the feeling that we are remembering a past event with the feeling that we are looking at the world, that we are imagining what is on the other side of the mountain, or that we are dreaming. These and other mental activities are conscious, too, but the consciousness is plainly and recognizably different. The term autonoetic has been used to refer to this special kind of consciousness that allows us to be aware of subjective time in which events happened. Autonoetic awareness (or autonoesis) is required for remembering. No autonoesis, no mental time travel.

A third clue is that mental time travel requires a traveler. No traveler, no traveling. The traveler in this case is what is referred to as “self.” But an ordinary self will not do. By some criteria at least—the well known Gallup mirror test, for example—some nonhuman primates (chimpanzees and gorillas) also have minds in which their own selves exist as entities different from the rest of the world, but if one assumes that they are not quite capable of the human-type time travel, their selves exist only in the present, whereas ours exist in subjective time.

The three clues—sense of subjective time, autonoetic awareness, and self—point to three central components of a neurocognitive (mind/brain) system that makes mental time travel possible. This (hypothetical) system is called episodic memory, and in this essay I tell its story. Like psychology, episodic memory has a long past but a short history. The concept was first proposed some 30 years ago (Tulving 1972), but it has changed drastically since then and has now reached a stage at which one can, as I am doing now, muse about it as a true marvel of nature.

Episodic Memory: From Mind to Brain

Annual Review of Psychology

Vol. 53:1-25 (Volume publication date February 2002) 
https://doi.org/10.1146/annurev.psych.53.100901.135114

Endel Tulving

Rotman Research Institute of Baycrest Centre, Toronto, Canada, M6A 2E1; e-mail: tulving@psych.utoronto.ca

 

Memory informs us, albeit imperfectly, of what has occurred, “thus far.” The reliability of memory correlates directly with the vividness of the remembered experience and its nearness in time. 

Conscious experience generates mountains of chaff. Memory is necessarily selective. Short term memory is essential for even the simplest coherent action through time. Our very personhood and sense of identity depends on it. Without immediate memory we cannot move from one moment to the next, lost and bewildered a meaningless present.

 

KNOWLEDGE QUESTIONS: CLASS ACTIVITY IN PROGRESS

Can a person suffering severe memory loss, maintain a sense of identity? Is a functional memory for the construal of experience a necessary prerequisite for personhood?  

Not all experiential events are of equal weight. What would be the consequences of total recall? We know that memory is necessarily selective. How do we distinguish between what is important and what is trivial?

Salvador Dalí (1931) The Persistence of Memory. Oil on canvas. Museum of Modern Art, New York.

Salvador Dalí (1931) The Persistence of Memory. Oil on canvas. Museum of Modern Art, New York.