Douwe Draaisma, professor of psychology in the Netherlands, is my go-to guy on the subject of memory. I tend to trust him because as a European he can access centuries of thought and experiment, beyond the limitations of the kind of dependence on dubious statistical experiments, let alone neuroscience, that form the dogmatic procedures of many American psychologists and brain scientists. He also writes clearly.
Neuroscience for example can tell us very little about memory, because memory is subjective; memory is an experience. So what brain neurons fire where is of highly limited value, except of course for the treatment of conditions involving the brain's role in memory loss or distortion. Properly conducted and interpreted behavioral experiments can be suggestive, and can support or contradict subjective insights. But these don't often require much computational power, so some of the best and most elegant of these experiments were designed and performed generations before computers.
In one of his books of essays, Why Life Speeds Up As You Get Older, he applies to that particular question the insights of psychologists (including William James), a philosopher or two, and novelists including Marcel Proust and Thomas Mann. This question is a gateway to the paradoxes of memory and time. Memory is important because that's one way we measure the experience of time. The answer to this question, at least to my mind, is not settled. We experience time according to a lot of individual factors. Some elements may ring true (a week's vacation flies by, but when you return home and to work, it seems you've been gone much longer, or that periods of anxiety, anticipation, illness and even boredom seem endless while they happen, though they seem shorter in retrospect) but others, I find, don't match my experience.
But one application of that question seems pretty universal among the people around my age that I know: that certainly after age 70, the weeks, the months and the years seem to fly by. They seem so short. The other feature of this feeling is that the past 20 or 30 years or more seem to have been much shorter in memory than the years that preceded them, when we were young. Those more recent years don't seem to have even happened.
Perhaps another approach to the question is to ask, why does time slow down when you're younger? One answer to this is the same as the answer to why people tend to remember events and people from their younger lives, and remember the experience more fully, but in later years don't remember much from more recent decades. It's because we are built to remember the new.
Remembering a new observation or experience--and the surrounding circumstances--is a survival skill, when those circumstances are encountered again. So of course we remember the first times, especially if it was an impressive, inately important event or experience. There's still a lot of mystery and individual difference in some of our early memories, but surely this is a big factor in many.
Then as life begins to repeat itself, there is less need to remember the details. We may remember our first car. But we probably aren't going to remember where we parked at the supermarket on an uneventful day three years ago.
But some memories do adhere because we continue to be new people, well into adulthood, not only because we experience new things, but because we are new people. Obviously we aren't the same at 10 as we were at 2, but we also aren't the same at 15 as we were at ten, or at 20 vs. 15, etc. for decades to come. Maybe the gaps are longer, and the differences may be more subtle, but we aren't the same at 40 as we were at 30.
And we really aren't the same at 70 or certainly 78 as we were at 50. We are brand new, in some ways. Our bodies are different, our physically processes including the glandular--all contributing to how we see the world, experience it, experience ourselves, and experience time.
After reviewing the theories and experiments, Draaisma admits that there is no convincing single answer to the question. Some speculate that our memory of time is related somehow to how long we've experienced time--that is, been alive. Which would help to explain how a month is endless at ten years old, when 12 of them add up to a tenth of your life (and you've only had any idea of what a month is for a few years.) The experience of time may similarly be related to the speed of biological processes, which tend to be faster the younger you are.
But I'd add another possibility. We've probably all noticed that we lost track of time while totally engrossed in some activity that required or evoked near total concentration, or perhaps engaged many of our senses and emotions. It isn't a rule of being old, but I am not alone in experiencing the moment more fully--that is, I'm not worried about where else I should be, or what I need to do next. I'm here, now--even if that means I'm totally present with a book, a movie, a song I'm singing or listening to, or a memory. It is present, and then it isn't, and something else is. I think part of this is a tendency towards entropy--I tend to keep doing something I've started, though it is harder to get started--that has noticeably increased in recent years.
It may even be that what we do remember, especially from youth, seems more full of time because we experienced it more fully, while later, the anticipation, the worry, the multitasking, obliterated a sense of being present in the time. So in a sense there is actually less to remember.
In many ways I remember my early past--the 20s are the statistical peak in some areas, like the popular music we recall--better than more recent decades. But, adding to the newness or firstness factor is that I've thought about those times more, I've told myself more stories about them. How much I really remember about more recent decades, once I put my mind to remembering and given myself the same kind of supporting cues, I have yet to discover.
Consciously or unconsciously, many older people compensate for the sense of time speeding up by increasing the newness in an outward way: by travel and new skills and adventures. Perhaps it is my introversion, but I find little appeal in that (though not having the means to do much of it does color my judgment.) I find my adventures in following curiosity about patterns of the past, as well as patterns in the world. And not just patterns, and not just intellectual understanding--maybe more the many fruits of perspective. So the past becomes new.
The process of revisiting artifacts of my own past in this protracted "History of My Reading" series for example, has been very involving on many levels, very absorbing. (It's certainly taking long enough.) Just living in the daily present while experiencing the evoked and fragmentary memories, finding myself in dialogue with them, takes up a lot of time. Though not much is accomplished compared to the past, the day is full. And it's over so fast.
