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Current time:0:00Total duration:8:02

Video transcript

how is perception organized well whenever we look at anything we need to make inferences so one of the things that we can do is take into account depth and depth allows us to get an idea of how far away something is how close something is and just it adds to our perception of objects and so in order for us to take into account depth of objects we can use a few different tricks so the first thing that we can immediately notice is that humans have two eyes so we have binocular vision and binocular vision basically gives us something known as retinal disparity retinal disparity so basically since our eyes our our eyes are about two-and-a-half inches apart and this basically allows us to get slightly different views of objects in the world around us so it looks for so for example let's imagine you're at a bowling alley when you're looking at some pins your left eye sees the pin the bowling pins in this angle and your right eye sees them in this angle and your brain takes these two images puts them together and gives you this image over here and this allows this this gives us some degree of depth of what we're looking at so that's retinal disparity so another way that our two eyes help us take depth into account is something known as convergence and this basically is trying to say that so when we're looking at things really far away are the muscles in our eyes are fairly relaxed and when we're looking at something really close to us our muscles in our eyes turn our eyeballs on towards the object and so our brain is able to look at how much the eyeballs are turned in order to give us another kind of depth cue so there are other cues that we can get that we don't need to eyes for so those would be monocular cues ocular cues and one monocular cue would be relative size relative size so relative size gives us a of the format' above an object so perceptual organization is organized into depth and then form so relative size would be let me just bring up a few examples so relative size would be this example over here where we've got two aunts and this aunt is perceived to be bigger and since it's perceived to be bigger we know answer fairly the same size so since this and is perceived to be bigger we perceive it as being closer to us even though we know these two aunts in real life are the same size but since this guy is bigger we think of it as being closer to us this we really only need one eye for we can see the relative size of things and infer the proximity of the object to us which is one eye another monocular cue is something known as interposition so interposition would be this example over here where you only need one eye to see that this rectangle is in front of this oval and we can infer that since the rectangle is in front of the oval that the rectangle is closer to us another monocular cue is relative height relative height so relative height would be this example over here relative height is basically saying that objects that are perceived to be higher are perceived to be further away than those that are lower so this rectangle over here this one over here is higher up than this red rectangle over here and so because it's a higher and based on all the surrounding cues we perceive it to be as further away but in fact they are the same exact shape they're the same exact height it's just that this one is placed physically higher than the red rectangle and so we perceive it to be further away so that's relative high and that's a monocular cue and one more macular cue is shading in contour so we can actually use light and shadows in order to get an idea of the form of an object so this these two images over here actually the same exact images that this one is flipped over so we took this image we flipped it upside down and now we see it over here so in this image we kind of see this little contour it looks like a crater whereas over here it looks more like a like a volcano a mountain so based on light and shadow and the shadows of an object you can kind of infer whether it's a crater or if it's coming out of the earth like this so these are some an ocular cues so those are the monocular cues that we can use to get information about the form of an object there is another degree to perceptual organization and that is motion so whenever we perceive an object we have to categorize whether it's moving or not and so there's one interesting monocular cue known as motion parallax motion parallax or relative motion and what this is basically saying is that when you're in a car and you're driving around the things that are closest to you appear like they're moving really really quickly whereas things further away from you appear like they're moving really slow so if you've ever driven down in in a desert or something and looked off in the distance and seen mountains you're looking at mountains the mountains look like they're moving really really slowly whereas things like cars right next to you or the road looks like it's moving really quickly and so that is relative motion and that's a monocular cue you can get an idea of how far away things are based on how much they move as you move and one other perceptual category is constancy and there are a few different types of constancy so there is size constancy so over here we have size constancy so when we look at these two ladies over here we can see that this lady is bigger than this one over here so this lady has a bigger image on our retina than this one does yet we know that these two one are more or less fairly the same size so even though this woman has a bigger retinal image than this one does we know that they're fairly the same side so that's size constancy there's something known as shape constancy so shape constancy would be over here so here we have a door it's a rectangle and as someone is opening the door the shape that we actually see changes a little bit so we actually look at it it's no longer a rectangle it's more of this trapezoid so it's actually changing its shape so the image that door casts on our retina is actually different yeah we know that the door isn't changing shape it's still a rectangle it's just that it's getting open so our perception of the door remains the same we know it's the same shape it's even though it's casting a different image on our retina and one other type of constancy is color constancy so color constancy so here we have a red cup and despite changes in the lighting we know even though over here this red appears to be brighter than this red this red over here this part of the cup looks darker even though the actual color that is falling on our retina is different we know that the cup is actually the same color so that is color constancy