[MUSIC]. Okay. So, we're going to talk about what's the biggest challenge for perception? And the biggest challenge is interpretation. What, does all this neural signaling that, that the brain gets, what does it mean? What does it amount to? And the bottom line, the thing to remember always is we are not cameras, and we are not tape recorders. We are very, very imperfect, perceivers of what's going out, on in the world. And one of the ways in which we can see that is by looking at illusions. In this segment, we are going to look at optical illusions and auditory illusion, and then a somatosensory illusion. Okay. So, here we have a what we have is three circles, and I think most people here would see a triangle. The triangle is in white. There's really no triangle there, not like there is here. But you're, you're seeing a triangle in its absence just as much as that, as in its presence. Another way to look at this is, to see how this, as I move this, you can see that there's a line that that forms. You see this line, so you're, you're interpreting that where it does not exist. Another example is here. These two squares are the same. This square looks very square. It looks like it has right angles, and straight sides. This square not so much. It looks like it has concave sides. So, you probably don't even believe me that they're the same. I'm going to show, you they are. So here is a square, and I'm going to move it. Looking squarish, right? Looking very right angled, straight lineish. And now look. Oooooooh. Things are happening, sides bending. That looks a little, con, convex. Now look it's switching and now look these are starting to look concave and now it's concave, but this is the same thing. So bottom line, why are we bad eyewitnesses? Not because we know, want to be bad witnesses. Not out of any lack of motivation. We're bad witnesses because that's the biology. We are not perfect cameras and perfect tape recorders. We interpret what we see. A big piece of what we interpret is expectation. And [COUGH] and there's, just, it's just an imperfect it's imperfect system where we are not recording exactly what's outside of us, what's outside in the, in the outside world. In, in vision, in auditory or in, in touch or in anything. So, those are all, optical illusions and what we are going to now look at is an auditory illusion, or we're going to listen to, an auditory illusion. [MUSIC]