Time seems to pass more quickly as we age. Why does life seem to be going faster the older we get and what do scientists say about that?
Maybe there’s an upside to time passing more quickly: waiting is more pleasant.
OMG, is it that late? Suddenly it seems like the party might be almost over. We look around. We check the calendar. How did that happen so quickly?
But wait a minute. Is it really true that the arrow of time flies faster the older we get?
It seems that way. The hours pass like minutes, the days like hours; weeks, months disappear, winter turns to spring and summer into fall. Get out the winter clothes, put them back and put them back again. There’s a thick layer of dust where you just dusted. Your ten-year-old god-daughter is getting divorced and has three children. You try to remember not to gasp and say, “You’re sooo grown up now,” to your friends’ children who are now in medical school or looking for a job. All at once a couple or three decades have fallen away. The eighties look ridiculously tacky, even worse than the seventies once did. Friends are retiring. Having hip replacements. Getting awards for career achievement. Or not.
At this rate, if things keep speeding up, it will all be over just like that. (Snaps fingers.)
We know this is true because we all experience the same thing. The idea that time speeds up the older we get has been commonly accepted more or less since people started noticing they were getting old.
But in recent years, scientists, always looking for objective truth, have attempted to verify this subjective phenomenon. In 1975 a guy named Robert Lemlich did a study asking people to say how long it took for a year to pass. The results confirmed the obvious: older people said they thought a year passed more quickly than when they were younger. This did not really prove anything we didn’t already know. (Although Lemlich claimed to be able to calculate that at the age of 20 we are already halfway through the felt experience of our lives: the next 60 years will seem to pass as quickly as the first 20.)
A year was perhaps too long a measure. So other scientists did tests comparing the abilities of 10-year-olds and 72-year-olds to estimate the passing of seconds and minutes. Apparently 20-year-olds are best at this – 20 seems to be the peak age for everything, except, of course, wisdom, knowledge, and experience. Ten-year-olds are the worst.
But the results seemed to be contradictory. It turns out that everyone thinks seconds and minutes pass more slowly than they actually do when looking forward, but they pass even more slowly after about 20; and all ages think time passes more quickly than reality when looking back, but retrospective time passes ever more quickly after adulthood.
I would guess that most of us, even those of us with failing brains, could more or less guess how many seconds have passed if asked to focus on it. We do that all the time when we put something in the microwave and forget to turn the timer on. It’s only when we are not focused on the immediate present, when we are thinking about something else, or looking back, that the passing of time seems to have gone faster. Or slower if we are in pain or distress.
Which brings up the question of what is chronological time anyway? And who decided how long a second is? We can all see the passing of a day: the sun goes up and goes down. This is our circadian rhythm, our real-time biological clock. Our natural life functions, including body temperature, metabolism, and aging, are geared to this mechanism, which is controlled by the suprachiasmatic nucleus located in the back of the hypothalamus behind our eyeballs. This is a fact.
Some days are longer than others, both objectively and subjectively. But how did a solar day get to have 86,400 seconds? (That’s only an average; the actual amount of seconds varies.)
It’s not just us slowing down. The earth’s rotation is slowing too as it wobbles around the sun with us on it watching the seasons change, our children grow, our friends turn grey and fat around the middle. Solar days are getting longer. Does this give us more time? I don’t know. But in 1967 they changed the definition of a second. The International System of Measurements now defines the second as 9,192,631,770 cycles of the radiation which corresponds to the transition between two electron spin energy levels of the ground state of the caesium 133 atom. And no, I have no idea what that means. Or why they decided that. Except that maybe it is constant. Or not. Apparently at high altitudes the atomic spinning changes and also at different temperatures. So later they specified altitude and temperature in the definition too.
This atomic definition of the second is based on Einstein’s theory of special relativity, which I’m sure you are all familiar with.
Before that a second was just one-one thousand, two-one thousand, I think.
In any case it was the ancient Egyptians who divided up the day into 24 hours and then later around 2000 B.C. the Babylonians cut the hours into smaller units, all in multiples of sixty for some reason, the smallest unit being the length of a grain of barley, about one-tenth of an inch, which equaled 3.33 modern seconds. This was all considered apparent time and it varies as the solar day varies. Clocks began showing seconds in the late 16th century but they weren’t accurate. The invention of the pendulum in 1670 brought us the first real second and what scientists call mean time, which as best as I can tell is more or less absolute time now calculated in a highly complicated way based on, among other sources, a fictitious sun that moves uniformly and the radiation emitted from stars in other galaxies. But even the length of the mean solar day is increasing due to the slowing rotation of the earth, as mentioned above.
That’s real time, the time we all set our clocks by. And frankly, since it just goes round and round, repeating itself in the same way, I don’t see how we would notice it at all, at least in the calendar sense, if it weren’t for the fact that we are mortal, with an increasing sense of mortality as we observe our aging physical systems and calculate the number of years we might have left. But I’ve never had a very good sense of time.
Subjective time is something else and in a sense is both illusory and real because it is our experienced time. Philosophers, psychologists, and now cosmologists hypothesize that (1) subjective time is based on our overall information-processing rate and (2) the subjective experience of life’s duration is related to the total information processed.
Our information-processing rate supposedly peaks at that wasted golden age of 20 and declines after that. And according to the above theory, the decline in our information-processing rate is at least partly responsible for the perceived quicker passage of time that is associated with aging. The faster one processes and gathers information, the more one experiences in life, the greater will be the experience of time. A person who processes little information will have little subjective experience of time having passed.
I can see how, if our brains tick more slowly, like a clock running out of battery, more time might pass than we think. My problem with the above hypothesis is that, on a short-term basis anyway, processing a lot of information causes time to speed up, not slow down. When we are mentally engaged with a task we don’t notice time and it passes more quickly. And furthermore, according to their data, a person at 60 would still have an experience of the speed of passing time equal to or slower than a person of 10.
However, it does seem that overall acquiring a great deal of knowledge would give us a sense of a long life. And paying attention to what’s going on around you, learning new things, would certainly lead to a sense of a deeper experience of the present, for which, apparently, there is no agreed upon definition.
To my mind there is an upside to time passing more quickly: waiting is more pleasant. Three hours in an airport can seem like fifteen minutes now. Unless you are with younger people, who are notoriously antsy and would probably destroy the illusion by complaining, sighing, getting angry, asking what time is it, etc.
Do children really have a slower sense of time passing? Or is it that they have so little sense of time at all, so little sense of the past, so few memories? Maybe we only remember childhood that way, how it was to live in the present, when time seemed endless, and we were so impatient to move forward, and then as young adults to think that we could waste idle hours and days because there was so many of them: there would always be more.
We are wiser now.
And here is a wonderful short story by Steven Millhauser related to this subject:
 R.P.Gruber, L.F.Wagner, R.Block, and S.Matthews, “Subjective Time vs. Proper (Clock) Time,” in Studies on the Structure of Time, edited by R. Buccheri, V. di Gesù, and M. Saniga. (New York: Plenum Publishers, 2000), 55
 Ibid, 49.
 Ibid, 60-61.