Good morning,

Welcome back! How are you doing today?

I enjoyed the long weekend in the U.S. with close friends, the return of college football, and many ruby-throated hummingbirds fattening up for their pending journey south.

Here’s what I have for you today:

• One big thing. Our sense of time depends less on the clock and more on how we pay attention now and remember later. ⌚

• You have to check this out. Gen Z may be the first generation not to have a midlife crisis. The reason is not uplifting. 📉

Are you ready to jump in? 🦘

1️⃣ ONE BIG THING

Time present, time past.

When I left you two weeks ago, I was talking about time, in a relative way.

Let’s dive back in by imagining two scenarios:

In the first, it’s Friday. You’re lying on your couch at the end of a long week. It’s time to relax. You mindlessly grab your phone and start scrolling through Instagram. Scroll, scroll… Oh, that video was funny (AI talking babies, I hope). Now you're down a rabbit hole of those videos. Wait, is it dark outside? What time is it? How is it 7:30 pm? You’ve been scrolling for 90 minutes but insist it was only 15 minutes.

In the second, you're at the top of a tall building, near the roof's edge. In this scenario, you're an action movie star, so naturally, a villain is chasing you. Running to get away, you stumble over the roof's edge and begin to fall. What happens in movies like this when people fall? They shift the video speed into slow motion. Time expands. You take note of every detail. A memory from your childhood flashes before your eyes. Of course, at the last moment, you deploy your parachute. Or Superman swoops in. You get the idea.

On the ground, Jimmy Olsen asks you what happened. You can talk for ten minutes about a fall that lasted less than 10 seconds.

There are several factors in play in these two scenarios:

• Your experience of time in the moment vs your memory of time after the fact.

• The degree to which experiences are encoded as memories.

In scrolling social media (or other passive distractions), time flies by (in the moment) yet creates few to no memories after the fact.

When falling from a building, time slows down in the moment, yet it produces rich, long-lasting memories.

This is a curious phenomenon, isn’t it?

Researching these ideas, I discovered that, as a species, we have been thinking about time for a very… well, a very long time. In the 6^th and 5^th centuries BCE, which is considered the beginning of formal philosophy in Greece, Parmenides and Heraclitus proposed two opposing concepts of time.

If you want to learn more about ancient ideas on time, this is a great summary:

But, if you’re tempted to think this is just an intriguing thought experiment, let me reframe these ideas in a more alarming way.

Let’s run some disturbing math. 

When is midlife, exactly?

If you’re like me, when you turned 45 or 50 you thought, Wow, this might be the midway point of life.

How many people live to be 100? The answer is 3 in 10,000 people. Sure, that is better odds than yesterday’s Powerball, but only incrementally.

Statistically speaking, if you’re a man in the U.S., you are most likely to die at the median age, which is 74. That means you hit the midway point when you turned 37.

It gets worse.

If you tell a five-year-old they will get the new toy they desire in one year, that's about the same as saying they will get the toy one day in Mars Infinity Time. One year represents 20% of their life.

At 50, something that is supposed to happen in a year comes around in a flash. One year represents 2% of your life.

If we run the math with this "time as a proportion of life" approach, midlife is closer to 21.

(The above framework is adapted from this Instagram video. See, all that time-warping scrolling paid off in one small way.)

Now, as I’ll explain below, I don’t believe this framework—that our perception of time is based on “time as a proportion of life” math—is quite right.

But it gets your attention, doesn’t it?

Here’s the idea I’m increasingly fascinated by:

• There is a lot of focus on ways to extend the number of years we live (lifespan and healthspan), which is well-deserved.

• What if a better understanding of how time perception works and how memories are formed could extend our perception of life’s duration and quality?

If two people on their deathbed said, "I've lived a long and rewarding life," and one was 70 and one was 90, wouldn't it be reasonable to believe them both equally?

Let’s examine a preliminary framework more closely, which can help us better understand how time perception and memory formation work together.

Prospective time and retrospective time.

Let’s return to our two scenarios from earlier: scrolling social media vs. falling from a building.

The thing that separates our perception of the passage of time in the moment—which is called prospective time—is attentional focus.

People refer to our first scenario as mindless scrolling for good reason. It requires almost no mental attention, whereas falling from a building requires every ounce of your mental attention. Research done in 1985 showed that as cognitive attention increases, the perceived passage of time slows down.

When you first learn to drive, your full attention is required for every move. A five-mile drive will seem to take a long time. When driving becomes fully habitual (no cognitive attention needed), the same drive will go by in a flash.

Unless you are stuck in traffic and watching the clock. In this case, watching the clock is its own act of mental attention. Research done in 1997 showed that the more attention you place on the passage of time, the slower it appears to move. The watched pot never boils.

So, when it comes to our experience of time in the moment (prospective time), attention is the variable with the biggest impact on your perceived speed of time.

However, when you finish 90 minutes of scrolling social media or the 10-second fall from the building, how do you estimate the time each took after the fact?

The thing that separates our perception of the passage of time after the fact—which is called retrospective time—is memory density.

What impacts your judgment of how long something took after the fact?

It is based on the number of distinct events or experiences remembered in a particular time window. More memorable, dense, or varied experiences make the period feel longer, while monotonous or uneventful periods feel shorter.

The ten-second fall—packed with rich, multisensory experiences—seemed to take forever.

So, regarding our experience of time after the fact (retrospective time), memory density is the variable with the biggest impact on your perceived duration of time.

Attention and memory-density beats time ratios.

Yes, you can look at a five-year-old and say that one year is perceived as 20% of their life experience, and thus, it feels very long.

But I think it is more illuminating—and more actionable—to examine the five-year-old's summertime experience. Nearly everything they do is new, requiring their full attention (except perhaps watching an iPad). Time moves slowly in the moment.

All those new summertime activities are cognitively engaging and emotionally rich, creating a much higher density of memories. Summertime feels very long after the fact.

If the fifty-year-old's summer doesn't work this way—if it seems to fly by and leave fewer rich memories in its wake—this is due to many variables that can be modified.

It is true; you can only do something for the first time once.

But can you purposely bring more true attention to the things you do?

Can you find more things to experience for the first time?

Can you find more ways to make experiences emotionally rich and enhance their impact by savoring them more?

Your goal is not to extend perceived time in the moment (prospective time). Two hours can seem like 20 minutes as you (1) scroll social media, or (2) share stories over a meal with a dear friend.

In both scenarios, time flies by in the moment, but the emotionally rich experience with your friend encodes the density of memories that are the building blocks of life satisfaction.

Next week, we’ll examine how this happens, exploring how you combine a series of present-tense experiences into a single memory.

Thanks for reading today, my friend.

If today’s newsletter headline rang a bell for you, it is the title of the memoir from the late, great Senator Bill Bradley.

Kevin

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