The human can do some remarkable things, and what we're going to see is a brief video on a volunteer person who put on goggles that turned the whole world upside down, and let's see how she responded to that. [MUSIC] >> For another clue to the brain's remarkable adaptability, consider Susanna Fines, a London art student who has agreed to undergo a curious experience. In order to appreciate this, we need to review how the visual mechanism operates in our normal everyday encounters. For example, when an object appears in our visual world, the image passes through the lens of the eye and in that process, it is inverted on to the retina. The image is then passed along the visual pathway to the visual cortex at the back of the brain, where it is perceived as being right side up. >> If I could have a look at these most unusual spectacles on you. >> For one whole week, she will see the world upside down, inverting once again, what the lens and the eye does anyway. Our brains correct for this inversion. Now hers will be forced to make yet another correction. Will she be able to make sense of an upside down world? >> [INAUDIBLE] God, that's really weird. I'm sure I'm holding the cup up. >> At home, an hour later, the world is still bewildering. >> Got it. It's funny, I just suddenly do it. [SOUND] Lost it again. Oh, yeah. Extraordinary. >> On the third day, Susannah tries to write her name without looking. [INAUDIBLE] trying to stop. It seemed worse and worse, I could read that end but not the rest of it. Shall I try and write it? Now, if I can draw. >> Once she looks, she is able to invert the letters completely. Clearly, in three days, she's made progress integrating upside down seeing with upside down moving. >> There now, I can read that quite easy. >> On Susannah's final day, she tries to draw. With a week's practice, she can now sign her name to the drawing right side up while looking. The seeing part of Susannah's very flexible brain has somehow matched the unchanged world to her altered vision. >> All right, I've been wearing them for a week, I'm going to take them off and try and walk across the room. I don't dare do it. This is terrifying. Oh, goodness! It's red, surely. That is just so incredible. I just feel everything all around me, it's amazing. >> And now, Susannah Fine's brain has managed yet another inversion of the image. >> An extraordinary feeling. >> And this time, it's taken just one hour. >> And then suddenly, I just feel as though nothing ever happened, if you look around. >> [SOUND] >> Everything just seems completely normal again. [SOUND] >> This basic pathway of vision is therefore flexible, plastic. It's ready to help us adapt to a world that changes. >> Now you didn't need me to tell you that our brain is better than a chicken's brain but this is amazing, to have one creature that just cannot adapt to some simple change in its visual world, and humans who can switch back and forth from upside down back to where they were before and do all kinds of complicated things. Now what that means is that the whole evolutionary process has pushed the processing and the plasticity back into the brain. So, our visual system, the eye part of it is pretty complicated but compared to what we do with our visual system, it's just the tip of the iceberg. Most of our seeing and visual processing has just taken the basic raw information and pushed it back into the big computer where it can make all these adjustments as we go though a changing world. Okay, so let's step away from that theme for a moment and go to childhood and ask whether the human childhood is special in any way. Again, I think the answer is yes. The data support that. Certainly, nearly all of our cultures think childhood is important. Poets think childhood is important. The childhood shows the man as morning shows the day. 'Tis education forms the common mind. Just as the twig is bent, the tree's inclined. The child is the father of the man. All different ways of expressing the idea that our childhood is a very important part of our life cycle. I'm going to talk to you about three evolutionary advances that are related to this. One of them, a longer lifespan, the other, neoteny. And the final one, the importance of a very long childhood. Before we move on to the next slide, I want to make sure that you understand the term lifespan. It is different than life expectancy. Our life expectancy now is somewhere in the 70s. At the time our Constitution was being written, life expectancy was probably somewhere in the 50s. Back in the Middle Ages in certain parts of the world it was probably, down in the 20s and 30s. Yet, in each of these historical periods, where life expectancy was very different, lifespan remained constant because there were always people who would live to about 100 years of age always. No matter what the life expectancy is because some of them just basically, dodged all the bullets. The lifespan of the white-tailed deer is somewhere in the neighborhood of 10 to 12 years. The life expectancy of the white-tailed deer in New Jersey is about 18 months. They are really bad at crossing the street. So, let's look at lifespan. A few years ago, my daughter got married, and her now husband gave her a diamond as an engagement symbol because diamonds last forever. I don't know how strong the relationship would have been if he had given her a hamster, instead of a diamond- >> [LAUGH] >> Or a gerbil because they don't last very long. >> [COUGH] >> They don't last very long. So- >> [COUGH] >> You see a gerbil, their lifespan is about three years. A cat, about ten years, sometimes more. Elephant 75 years, a whale 200 years, and biologists have been kind of interested in that, trying to come up with some sort of a reason for it. And one reason that seems to work fairly well, lot of variability, but it works fairly well, is heartbeats. And mammals live for approximately, 800 million heartbeats. So, if you take your little gerbil, and hold it up to your ear to listen to its heartbeat, he's probably going to bite your ear, but you're not going to be able to count his heartbeats, anyway, because it's going to be turning along at 8, or 10, or 12 beats per second, faster than you can count. Cat, heartbeat going faster than yours, but not nearly as fast as a gerbil. Elephant has a very slow heartbeat, and if you want to listen to the heartbeat of a whale, it might take a little patience because it's going to be going lub Dub. >> [LAUGH] >> It takes a long time to reach 800 million. And probably, make a pretty good engagement gift. You'd need a large apartment. So, you might want to get on a spreadsheet, or something and figure out, how long it takes you to reach your 800 million heartbeats. Something on the order of maybe, 70 per minute, 60 minutes per hour, and so on and so forth. You can do that calculation. You might want to sit down, when you get to that final number, because I hate to tell you this, you're almost there. You will reach your 800 million about the same time you graduate from Rutgers. It's about 22 years, yikes. For reasons that still remain unknown, we end up having a lifespan about three times longer, so when you draw that chart of a whole bunch of different mammals, and how many heartbeats they tend to live. It's a pretty variable graph, but even with that variability, humans are off the chart. For some reason or other, we are given a good bit more time, a good bit more heartbeats for our lifespan. Eubie Blake, once said, on his 100th birthday that if I had known I was going to live so long, I would have taken better care of myself. That we do have the ability to live for a long, long time, and there may be some evolutionary reasons why that works. Let's look a little bit at childhood, is that the beginning of each of these lifespans. There got some yearlings being show there. A horse that's a year old, galloping around the paddock. A dog that's a year old, looks a lot like an adult dog, but still has a kind of youthful appearance, can do all sorts of complicated dog-like things. There's a little chimpanzee there, swinging on a rope in a zoo from one rope to another. A moose, it's a year old, wading out into the lake to eat something of the bottom of the lake. Little year old lion there, sleeping, having a little nap on the rock. But still, a magnificent creature, if you were to wake him up would be able to do all sorts of abilities, even though technically it's a cat. And then There's humans. Happens to be my granddaughter. Oh, she's as smart as she is cute, but at one year old, pretty much just sat around, and about a month later started taking a few steps and walking, like a all year olds tend to do. Pretty pathetic compared to all of these other creatures. >> [LAUGH] >> So, we're off to a very, very slow start. With our childhood, just from a purely physical standpoint. You all kind of reacted to these creatures, especially the little one, oh, cute. Well, that gets us to neoteny. Even these little line drawings here, you probably would all agree that they're cute. We've got the cute little person there, cute little bunny rabbit, and the puppy, and even the little bird is kind of cute and psychologists are never happy just with a report from people that oh, yeah these things are cute. We want to know why, we want to measure it, we want to have it be replicable, we want to make science of it, and it turns out that was pretty easy to do. Just show a whole bunch of people all kinds of line drawings that differ in one dimension or the other, run the results through a computer and you can find out that cuteness has three main variables. One of them, a round head, tends to be somewhat spherical. Big eyes. Now, actually, the eyes are not big. It's just that, because of some of the detailed structure of the eyes, the eyes of infants tend to be about the same size they're going to be in adulthood. Relatively speaking, they're large compared to the remainder of the head and a receding chin, it's not so much that it's receding as it's not yet protruding and those three things make up cuteness. That's in childhood early development of all of these creatures and it's pretty common across most of the species that we're familiar with but then something happens as we age. Not so cute anymore because the head is not as round, and the eyes have gotten smaller relative to the head and the chin has grown up. Look at what happens to our close relatives, here. The infant on the left and I do not know if that is mom or dad on the right but lots of cuteness has been lost from childhood into adulthood. We can measure how much cuteness was lost because we have a mathematical formula for it and what we find is that some creatures differ in terms of how much cuteness they lose and humans remain cuter in adulthood than these other creatures. Mathematically proven, we remain cuter, even in the most challenging cases. >> [LAUGH] >> [LAUGH] We remain cuter and it's not really just that we think we remain cuter, we've got the math to prove it. And that's called neoteny. >> It's the progressive maintenance of child-like, call that cute, child-like features into adulthood. So we look more like babies in adulthood, than other creatures do, is that important? Well, it probably is. If you're walking across campus and see a dog running across the street in front of a campus bus, if it's a little puppy, you will probably foolishly go running out and try to snatch it from in front of that bus. If it's some old dog with its jaw protruding and its beady little eyes, and its non round head, you'll say, well, I hope he makes it but I'm not going to run out there. We tend to be more nurturing and helpful and nice to cute creatures and that probably contributes to human's ability to be social creatures and live in tribes and things like that. Now, obviously, it doesn't always work. One can only imagine how vicious the human race would be if we weren't cute to have something to mute it down a little bit. We're plenty willing to maim and kill our fellow humans, as it is but cuteness plays a role in the way we interact, and just think about some of the language that goes into romantic situations. Full grown adults call each other baby, and it's kind of sickening. >> [LAUGH] >> But it all feeds into this neoteny thing. So now, start to think about what we've got here. We've got the brain doing the bulk of the processing of our information. We have, for reasons unknown, a very long period of time to live. We have a very slow and long childhood that may go on for as long as 30 years. Seriously, a 30 year childhood? Most of our other mammals are dead by then and we're just getting out of our childhood. That is probably one of the single most important evolutionary advances, the long childhood because what happens is that it gives us all of that time to really put our personal stamp on our brain. So all of our experiences that we have throughout this long childhood changes and molds and adapts the detailed circuitry of the brain, so that we build into our brain, the experiences of our individual lifetime. Now a parallel to that same thought experiment, turning the clock back on evolution, 40,000, 40 million years, whatever, and letting it start over again, it's going to be a different result. The same thing can happen with ontogeny, with your own individual life. If you could turn the clock back to the time of your birth, or even more importantly, to the time of your conception, if you could turn that clock back, have everything the same at that time, and then turn it loose, your brain today would be a very different brain than the one you actually have because your brain has depended on the precise experiences that you have had every day of your life. Most other creatures do not have the luxury of that childhood and the building of brain, they get an off the shelf brain that doesn't care if they circle lights, doesn't care if they never get the seed, pecking off to the side here, and doesn't have the processing and the plasticity that the human brain has. So the 30 year childhood to allow that to happen is indeed, a very important gift that humans have with their human brains. Thank you. [APPLAUSE]
