[MUSIC] So in the last segment we talked about perceptual habits if you will. How we see what we expect to see, or the pathway that enables us to see what we expect to see. But, how about if we're trying to teach ourselves how to see something? So, for instance, there's a game here, in the United States, called Where's Waldo. And you have to find this one little cartoon character with a particular appearance in a sea of color and patterns, and the first time you do it it takes you a long, long time, and the second time you do it it takes you slightly less. By the 20th time that you do it, you can go boom, there's Waldo. Well we do that not just with Waldo, but we do that all the time. We become experts, we become perceptual experts. And so an example is, if you wanna learn how to find mushrooms. These are morel mushrooms, they're unbelievably tasty, I recommend them to everyone. But if you just went out into a forest, they would not pop out at you like this picture does. In fact they'd be in at the base of a tree covered with foliage, and you could spend hours looking for morels and find nothing. And then you go with an expert, and that expert can teach you, show you and by experience, by visual learning you will learn to attend to those particular optical characteristics that are going to tell you there's a mushroom. There's going to be a mushroom. And so you know when to expect to see a mushroom, and you can see the mushroom from the very faintest of clues. So this is the kind of thing that allows us to find mushrooms, find fossils. Not me, but I know there are many people that can identify the make of a plane or the make of a car from a fleeting image. People that are very good birders, that can see a bird flying by and know exactly what that bird is. These are all examples of learned perceptual habits, of learning how to see with very little information, and that's really the beauty of perceptual learning. Our ability to attend to information in our world is actually dependent on an even higher process. And we can see that through a very peculiar neurological deficit called hemispatial neglect. And hemispatial neglect happens when there is either a brain tumor or a stroke that affects the right hemisphere in an area around here, somewhere in the parietal, the parietal-temporal junction can produce hemispatial neglect. And in these individuals, the left side of the world does not exist. They can't see the left side of the world, you can't turn them to the left, they don't turn their eyes to the left because why would you turn your eyes to a place that doesn't exist? So this is, I think, a very dramatic example of how the world that we live in is only that world to which we attend to. If we don't have attention, if we don't attend to something, it doesn't exist. And in hemispatial neglect there's this entire half of the world that doesn't exist. Okay. So attention is very critical. We don't understand the basic mechanisms that support attention extremely well. It's a very rich area of research. But we will leave it at that, and we are gonna go on to one of the most important functions of the cerebral cortex, and that is memory. [MUSIC]
