How Old Can We Get?

Hey, Vsauce. Michael here.

And today we are going to talk about time, specifically, how much time we have. What's the oldest a person can ever be? Well, the world record for the world's longest living person belongs to Jeanne Calment, a French woman who lived to be 122. Right now, at this very moment, there are only 37 people alive who were born in the 1800's. Those 37 people have lived in three different centuries.

But, as medical knowledge expands and our understanding of biology improves, people are living longer, and longer. In fact, scientists believe that, based on statistics, the first person who will ever live to be 150 has already been born. It could be one of you. But, according to the math, it's probably someone who was born last year.

Here's the thing. As humans get older, the likelihood of them dying increases, but there are some types of animals that have what is called Negligible Senescence, also known as biological immortality, and these types of animals have never been observed to actually age. Animals, like the Hydra, can only die because of accidents, disease, or predators.

The world's oldest living individual tree has clocked in at more than 4,600 years old. It's called the Methuselah Tree, and it exists somewhere in this forest. Government officials won't actually release its exact location to protect it from vandalism, but it's out there.

The lifespan of an organism can be even longer than that if you include clonal colonies. For instance, these Quaking Pines all look like individual trees, but they're actually all clones of one genetic code. They all share a root system, and the root system continues to make more trees, meaning that these trees are all part of the same organism. Experts have calculated, based on the roots system, that this one, male Quaking Pine has been around for at least 80,000 years.

But let's get back to humans, and rather than talking about how time is, let's talk about how time feels. Intense moments of your life are remembered as lasting much longer than times that were relatively dull. Psychologists say that the reason for this is that our brains take deeper and richer memories of events that are novel, or events that are intense, than ones that aren't.

When your experiences are intense and novel, you're not remembering more things about it, but you are making more copies. Rather than just making normal memories, during stress the amygdala gets involved and also remembers things, and many people believe that is why intense moments are remembered as lasting longer.

This phenomenon becomes quite mind-blowing on a macro-scale. Think of it this way: when you are a one-year-old baby, one year represents 100 percent of your life. But when you turn two years old, that second year was only half your life, and the next year you live through is only a third of your life, and by the time you turn 80, one year only represents an 80th of your life. Those percentages are important because they may explain why your childhood feels like it took so long, but as you get older, the years seem to fly by. You have more novel experiences when you're young.

You first learn a language, you first see your mother, you first learn to walk, you have your first kiss. These are all deeply and richly remembered by your brain, and so, later on, it feels as if they took longer to happen.

Now, here's what's really mind-blowing. Let's look at a graphical representation of the percentage of your life that each successive year is. The first year is 100 percent, the second year is only half, the third year is a third, and so-on will go all the way out to 80.

Now, using this representation, under this model, when you turn 80 years old and look back at your life, the point that feels like the middle isn't your 40's, it's your early 20's. The good news here is that the more novel things you do, and things you see, and places you visit, and people you meet, the slower time feels, and the more rich it feels.

So, go out there and do something cool, do something weird, do something new. Subscribe to Vsauce if you haven't already! And as always, thanks for watching.