MICHIO KAKU: Well, if you look at the history of the evolution of the brain itself, you realize that the brain is basically in three parts. The back of the brain is the so-called reptilian brain, the oldest brain, the brain of space, the brain of a reptile, that has to locate its prey, its mate, and understand its position in space; that's the back of the brain. As we evolved to the front, we evolved the monkey brain, the brain of society, hierarchy, emotions; the brain that tells you about manners, about etiquette, how to respect your elders. That's the central part of the brain, the monkey brain.

Then the front part of the brain is the most important part for us, that distinguishes us from the animals. You see, the animals have a back of the brain, the spatial brain. The animals have a social brain, like wolves. They have a pecking order in the center of the brain.

So what do we have? What do we have that the animals don't necessarily have? The front part of the brain governs time. It constantly thinks about the future. It constantly reruns alternate scenarios of what could be the future, plans, dreams, strategizes. Animals don't do that.

When animals hibernate, it's not that they say, 'Oh, I've got to hibernate. Time for me to get ready to hibernate.' Nope. Animals simply say: Instinct tells me I've got to get ready, and I've got to hibernate.

So what is it that makes humans different from animals? And how is it related to success as a human? It's the ability to see the future, to see the future in all its messiness, to be able to re-create scenarios of the future which are realistic.

Now, let's go to a psychologist and ask him a simple question: Is there a test that correlates children with success in life? That's a big question. Success in life and childhood—is there a test that you can perform? It's not perfect, of course. But yeah, there is a test that's been done around the world. You test kids, and a few decades later, you try to find out if they're successful or not.

And you find that, yes, there's one characteristic that does seem to correlate with success in life, lower divorce rate, higher income, higher social status. What is that one characteristic? It's measured by the marshmallow test. The marshmallow test—you give children the option of eating a marshmallow now or two marshmallows a few hours later. And then you follow these kids for decades in different countries. Now, it's not perfect, of course. But you'll find that there is a measurable correlation.

Now, what's the lesson here? The lesson is the kids who wanted two marshmallows later saw the future. They are the ones who want to plan, the ones who want to go to college, the ones who want to make something of themselves, that hold out. Now, who are the ones who simply get that first marshmallow? It's not perfect, but a lot of them want shortcuts, shortcuts in life, the easy way out.

Now, let's do a science experiment that all of us can perform. If you've graduated from school, and you meet your friends years later, like at a reunion, mentally, you ask yourself a simple question. Where are my friends now? After so many years, I haven't seen them. I think maybe they're successful. Or I know this guy. This guy's a loser. He's not going to go anywhere in the world.

And you meet them. And yeah, you make some mistakes. But I found that, when I go to my reunions, yeah, the people I thought would be successful became successful. And the ones I thought took shortcuts, yeah, they took shortcuts in life. And so that's why I think the measure of success is seeing the future, that is, running simulations of the future over and over again, day-dreaming: Should I go to college? Should I get a PhD? Should I become this? Should I do that? Working out all the different scenarios, versus the shortcut: I can cut corners. I can steal here. I can fudge this. I could lie about that. That, I think, is the criterion for success in life.