Actual time and our mental time are very different things.

By Clifford N. Lazarus Ph.D.

Time is an amazing and fascinating phenomenon. It is believed to be a fundamental quality of the universe that, along with the three known spatial dimensions (length, width, and height), makes up what Einstein famously described as spacetime. What’s more, Einstein proved that time is relative and actually slows down due to gravity and acceleration. Hence time is relative, depending on its observer, rather than an immutably fixed constant everywhere in the universe.

But beyond the theoretical and practical applications of Einstein‘s theories of relativity, almost every human knows intuitively that time is relative—because it seems to pass much faster the older we get. Hence, how a clock measures time and how we as humans perceive it are quite different. This speeding up of subjective time with advancing age is well documented, but there is no consensus on the cause.

A typical explanation that might explain some of this perception is the simple fact that for a 10-year-old, one year represents 10 percent of their entire life and even 15 to 20 percent of their conscious memory. But one year for a 50-year-old represents less than 2 percent of their recallable life. Thus those long days in school and almost endless summers of grade schooler’s childhoods, and the rapidly fleeting days, weeks, and months that most adults experience.

Another intriguing hypothesis stems from the fact that young children have faster heart rates and faster breathing rates than adults. It is likely, therefore, that their brains’ electrophysical undulations and rhythms occur faster as well. Just like the heart’s pacemaker slows the heart’s rhythm as children age, it is possible the brain has a pacemaker as well that slows as people age, and this “neural metronome” provides an internal sense of the passage of time.

Indeed, if you ask a young child to sit quietly, close their eyes, and state when a minute has passed, most children will report a minute has elapsed in 40 seconds or less. Run the same experiment with adults and seniors, and they will likely report a minute has passed in 60 to 70 seconds. Hence, children’s brains “beat” faster than adult brains, thus allowing them to have more conscious experiences in a given unit of objective time. This, in turn, leads to the subjective passage of time moving more slowly for children than it does for adults.

A fascinating explanation that extends this neural pacemaker theory has recently been posited by Professor Adrian Bejan. He presents an argument based on the physics of neural signal processing (Bejan, 2019). Bejan hypothesizes that, over time, the rate at which we process visual information slows down, and this is what makes time “speed up” as we grow older.

This is because objectively measurable “clock time” and purely subjective “mind time” are not the same. Unlike the number of a cesium atom’s vibrations (the current agreed-upon definition of one second), mental time—memory—is never veridical and universally agreed on. It is a reconstructive process that involves a great deal of mental imagery (i.e., A. A. Lazarus, 1978). Bejan believes time as we experience it represents perceived changes in visual stimuli. We know something happened because we see change. And things always change in one direction; from cause to effect. We will never see a broken glass reassemble itself and jump onto a table from which it fell.

In this way, our experience of time is always a backward-looking process, reliant on memory and is thus relative, but not only in the way Einstein meant it. Of course, memory is much more than just a sequence of images, there are other sensory dimensions to it as well. But our predominant sense is vision and therefore a great deal of our memory is visual.

We can think of a camera, film, projector, and movie as metaphors to represent a central part of visual memory and its relationship to time.

Like frames in a movie, the more frames one sees in a second the slower the image appears to pass. The fewer frames one sees per second the faster the image seems to move. In other words, slow motion reveals many more frames-per-second than normal motion or fast motion. Bejan asserts that as we age our brain’s neurovisual memory formation equipment slows and lays down fewer “frames-per-second.” That is, more actual time passes between the perception of each new mental image. Children perceive and lay down more memory frames or mental images per unit of time than adults, so when they remember events—that is, the passage of time—they recall more visual data.

This is what causes the perception of time passing more rapidly as we age. When we are young, each second of actual time is packed with many more mental images relative to our older selves. Like a slow-motion camera that captures many more frames per second than a regular speed one, and time appears to pass more slowly when the film is played.

The root cause of this subjective, temporal gearshift, Bejan argues, is that the size and complexity of our brains’ neural networks increase as we mature and continue to age. This means electrochemical signals must traverse greater distances and span more pathways thus slowing signal processing. Moreover, aging causes nerves to accumulate damage that creates greater resistance to the flow of signals, further slowing processing time.

As Bejan puts it: “People are often amazed at how much they remember from days that seemed to last forever in their youth. It’s not that their experiences were much deeper or more meaningful, it’s just that they were being processed in rapid-fire.”

Of course, the phenomenon of time passing faster as we age is but one of the brain’s unknown, and possibly unknowable, mysteries. Classical physics has incorporated and moved beyond the seismic contributions of Einstein into the realm of quantum mechanics. Similarly, it is probable that, to glean the intricate and multi-dimensional workings of the mind, a quantum theory of consciousness might be needed.

Remember: Think well, act well, feel well, be well!

Copyright 2020 Clifford N. Lazarus, Ph.D. This post is for informational purposes only. It is not intended to be a substitute for help from a qualified health professional. The advertisements in this post do not necessarily reflect my opinions nor are they endorsed by me.

References

Bejan, A. (2019). Why the days seem shorter as we get older. Cambridge University Press.

Lazarus, A. A. (1978). In the minds eye. New York: Rawson.

Originally published at Psychology Today