Measuring the speed of perceptual time

From a scientific perspective, the speed of time is relatively fixed. Let’s call it calendar time.

From a personal perspective, time accelerates as you age. Days get shorter, years get shorter, in what can seem like a race to the end. Let’s call it perceptual time.

The speed of perceptual time is proportional to age and can be calculated as follows.

· Let’s assume (for arithmetic convenience) that a lifespan is 100 years. The midpoint is 50.

· Divide 1 by your age in years. Multiply the answer by the 50 (the scale midpoint).

· Divide by a constant (2.5937) so the perceptual scale range matches the calendar range, at 100.

The formula: [(1/age in years)x50]/2.5937 = the number of calendar years in a perceptual time years.

When you are four years old, a year is 25% of your life so far. “Wait until your next birthday” means “wait a quarter of your life”. An almost inconceivable period of time, for a 4 year old.

At age 4, one calendar year is 4.82 perceptual years.

When you are 25, a year is only 4% of your life so far. By the formula, it’s 0.77 perceptual years. A warning. The interminable summers of your youth are over. On the perceptual scale, slow time finishes when you are 19.

At 50, your perceptual year is 0.39 of a calendar year.

By the time you are 80, a year is just 1.25% of your life so far: 0.24 perceptual years. Your time is going 4 times faster than the calendar.

At 100, a calendar year is 0.19 perceptual years. Your time is going 5 times faster than the calendar. The model keeps working for any age past 100.

Does this represent reality? On average, I think so. A year when you are 4 does seem much longer than when you are 60, easily 4.82 times. The slow days of youth are gone when you leave your teens. And at 70 a day can easily flit past in just about three quarters of what it seemed at 50.

So, yes: your days, measured in your perceptual time, are getting shorter.

Writers may be interested in the creative use of perceptual time: see my Medium article Perceptual time, character and storylines.

Here’s a table of showing how many calendar years are in a perceptual year, according to age.

The total of the Perceptual column is 100.