Have you ever calculated how old you are in dog years? Or figured out what your age would be if you lived on Mars?

I know I have. Who hasn’t?

The formulas are simple enough. Humans live on average seven times longer than a dog so all you need to do is multiply your age by seven. And since Mars takes about twice the number of days to rotate around the sun all you you need to do is divide your age by two.

But have you ever figured out the difference in the feeling of time between the older and younger you?

We all have this sense that time is speeding up as we get older. I was reminded of this recently when the prospect of a 45 minute car trip brought my son to tears. 45 minutes of course doesn’t feel long to me NOW but I remember how it once felt substantially longer.

So how does 45 minutes at the age of eight compare to my experience at the age of thirty-five or perhaps more importantly what will 45 minutes feel like to me when I’m eighty?

In this post I want to show how you can simply and accurately compare your experience of time with those of a different age.

Why We Feel Time is Speeding Up

While there are a number of reasonable explanations for why time feels to be accelerating there’s only one that is any sense measurable.

Time speed-up is not entirely subjective. The feeling is a result of adding moments to our lives. Just as printing more money devalues the dollar so adding new experiences decreases the feeling of time. Each moment, as a ratio of your life, is literally becoming less than the one before. See my post Why We Feel Time is Speeding Up for more on this.

This rate of change is the same for every one. And because it’s the same, it’s possible to compare the feeling of speed between any two ages. Here’s how.

Comparing the Older Person to the Younger

So you want to know what 45 minutes at the age of 8 feels like to 35 year old or what 45 minutes at the age of 35 feels like to an 80 year old.

Use this formula when you want to know what the younger person experience would feel like to the older person.

1. Divid the older persons age by the younger persons age.
2. Multiply the given period of time by the answer to step 1

The equation looks like this: Time(Older Persons Age / Younger Persons Age).

What does 45 minutes at the age of 8 feel like to a 35 year old?

Answer:45 x (35/8) = A 35 year old would need to wait 197 minutes to experience what 45 minutes feels like to an 8 year old.

What does 45 minutes at the age of 35 feels like to an 80 year old? Answer: 45 x (80/35) = An 80 year old would need to wait 102 minutes to experience what 45 minutes feels like to a 35 year old.

Comparing the Younger Person to the Older

Now you want to know the reverse. What does the older persons experience of time feel like to the younger person.

1. Divide the older persons age by the younger persons age.
2. Divide the period of time by the answer to step 1.

The equation looks like this: Time / (Older Persons Age / Younger Persons Age).

What does 45 minutes at the age of 35 feels like to an 8 year old. 45 / (35/8) = Answer: An 8 year old would need to wait for 10 minutes to experience what 45 minutes feels like to a 35 year old.

What does 45 minutes at the age of 80 feels like to a 35 year old. 45 / (80/35) = Answer: A 35 year old would need to wait 20 minutes to experience what 45 minutes feels like to 80 year old.

Further Reflections

It’s interesting and fun to compare our experience of time with others. What’s not so fun, however, is finding out how much experience you might have left. I’ll tackle what this theory says about our future in my next post If Time is Speeding Up How Much Time Do We Have Left

A few days ago my family and I loaded into our minivan for a dinner out at a nice restaurant.  And my son like a typical eight year old asked how long the drive.  When I told him, he cried, “45 MINUTES! THAT”S GOING TO TAKE FOREVER!”

Forever?

45 minutes doesn’t feel all that long to me.  But of course when I look back I can remember a moment feeling like an eternity.  Time seemed to move slower when I was eight just as it feels to be moving more quickly now that I’m thirty-five.

Have you ever wondered why that is?  Why time feels like it’s speeding up?

There are a number of reasonable explanations for this apparently universal feeling.  But one theory is more objective than the rest.

Explanation #1: Time Flies with Fun

You’ve experienced how time flies when you’re having fun, right?  And drags when you’re feeling board.  It could be that as we age our experiences only get more engaging.  When we’re young we spend most of our time doing things others want.  But as we get older we find more freedom to do what we want.  Thus as fun replaces boredom we feel time speeding up.

Explanation #2: Routine Gaps in our Memory

But the reverse might also be true.  We remember new and fresh experiences more often than those that are monotonous and routine.  But monotony and routine characterize much of adult life. The result is that when we look back over our life we find memories tightly packed in the freshness of our earlier years but thinning as we grow older.  And so like a person who sleeps more and more each day, the decline in the number of  our memories causes us to feel that the days are simply going by faster.

Explanation #3: Inflating Experience

The subjectivity offered in these first two theories certainly play a role in our perception of time’s speed but there’s another more objective way to account for this universal phenomenon.

>It’s a mathematical fact that as a ratio of our life , each moment is becoming less than the one before.  Just as printing money eats away at the purchasing power of a dollar so each new moment eats away at the perceived value of time.

Think about it.  A year to a one year old is the whole of their life.  But at the age of two it’s half.  At three its a third. Four, a quarter.  And so on.

Our experience of each new moment is like continually squeezing more slices into an already whole pie.  With each additional slice all the pieces must get smaller. Everything gets smooshed. The distance between the slices grows shorter.  And like a car shortening the intervals between the lines on the road, we feel time accelerating.

But thankfully as you can see the rate of decrease isn’t constant.  It’s exponential.  While we feel time is speeding up it’s no where near the acceleration a child experiences. In fact all our lives the rate at which we feel time speeding up is itself slowing down.  Though we feel time speeding up it doesn’t feel like it’s speeding up quite as fast.

Besides offering an objective view of our experience, the inflation explanation provides a number of other useful benefits.

In my next post, How to Compare Time Speed Up Between Ages, I will show you how you can objectively compare your experience of time with those older and younger.   The next time you hear a child wine, “45 minutes!” you’ll know exactly how long that experience of time would feel to you.

Question:  Which explanation of time speed-up do you prefer?  Do you have an another alternative explanation?