My next milestone birthday is age 70, which is significant mainly because it is the biblical “three score and ten” – once regarded as the normal span of a human life. Never mind that very few people actually lived to be that old in biblical times or that the median lifespan in this country is now comfortably beyond that. The point is that few people outside my immediate family would think I had died before my time if I got no further than 70. Two of my three college roommates never made it this far. And my eight-year-old granddaughter recently expressed astonishment that she was unable to pin me in arm wrestling, given my advanced years. It’s all a matter of perspective, I suppose. From my vantage point -- and for many in my age bracket -- the wonder is that the years have flown by so fast. How did it get so late so soon?
Researchers have long pondered why time seems to speed up as we age. The pioneering psychologist William James linked time to memory, suggesting ”the foreshortening of the years as we grow older is due to the monotony of memory's content, and the consequent simplification of the backward-glancing view.” When we are young and experiencing everything for the first time, memories are vivid. James wrote, “But as each passing year converts some of this experience into automatic routine which we hardly note at all, the days and the weeks smooth themselves out in recollection to contentless units, and the years grow hollow and collapse.”
Researchers Dinah Avni-Babad and Ilana Ritov have since confirmed that people do indeed perceive time moving more rapidly in routine situations than in non-routine ones. However, evidence is somewhat mixed with regard to time speeding up as we age. A 2005 study by Marc Wittman and Sandra Lehnhoff found that every age group perceived time passing rapidly over specified intervals (week, month, year and decade). However, older subjects were likelier to report time passing more quickly over a ten-year interval than their younger counterparts. This accords with a psychological phenomenon called “telescopy,” where distant events seem nearer than they actually are, like distant objects viewed though a telescope. Presumably this phenomenon would become more pronounced as the distance from the object or event increases.
My earliest memory comes from the summer my family spent on a ranch in New Mexico when I was two and my baby brother was only a few months old. (My father was then a college professor, so he had the summer off.) The ranch owner had a pack of dogs that were as big as I was, and I seem to remember they got hold of my stuffed pony and dragged it in the dirt – but then again, maybe not. I also remember being bathed in the kitchen sink, or was that my baby brother? One of the problems with memories, according to neuroscientists, is that we aren’t really remembering the event itself; we are recalling the last time we remembered it. Our memories of memories get sketchier with each recollection, and details become garbled.
The fading of memory is one reason why we imagine a great distance has opened up between some long-ago event and now. But has it? There is a crucial difference between a span of, say, 70 years and a span of 70 miles. With mileage, you can always retrace your steps and confirm that you have traveled that distance. But with time, your starting point has disappeared into the past, and there is no going back. Even talking about traveling back or forward in time borrows spatial terminology that does not actually apply. Time has no physical attributes beyond the ticking of a clock, and it is not directly detectable by any of our five senses. Even to say that time speeds up as we grow older raises issues. Speeds up in relation to what, exactly? We assume there is some uniform clock-time against which our perceptions can be measured, but Einstein debunked that idea more than a century ago with his special theory of relativity.
William James was right to link time to memory, because our sense of time passing is really anchored in what we remember, including most especially our sense of time accelerating as we grow older. I know the summer my family spent on that ranch in New Mexico occurred when Harry Truman was president, before the Korean War, before my parents bought our first black-and-white TV, almost a lifetime ago. And yet my subjective sense of the interval between then and now is governed by my memories, which unfold not then but now. Once these memories are forgotten, there is nothing to anchor me to the past.
We think of the past as a place, like that ranch in New Mexico where I stayed with my family nearly a lifetime ago. But it is not a place we can ever revisit because it lives on only in our fading memories. If the past does not exist in any tangible sense, then what does that say about time passing? How do we measure the distance between two points when our starting point has disappeared? No wonder it has gotten so late so soon. The older we get, the more we discover we can’t look back without finding ourselves once again on the threshold of right now. There is a reason a long time ago seems like only yesterday; in reality, it isn't even yesterday.