 Hi and welcome back to this video course on biological psychology and in this video video 3.4 We're going to take a look at Gestalt theory Now what is Gestalt theory? Visual information is according to Gestalt theory is processed based on a few simple principles Gestalt principles and this is what is described by Gestalt theory and Gestalt theory I think it is Both historically and theoretically relevant because it is one of the most influential theories in psychology, I would say And it's still to some degree holds. It still describes quite accurately how we some aspects of visual processing It was developed in the early 20th century by a group of psychologists including Max Wertheimer, Kurt Kovka and Wolfgang Köhler Gestalt theory is essentially a set of principles That explain aspects of how we visually perceive the world So I will just walk you through the the basic Gestalt principles You will hear the principles phrased in slightly different ways in different descriptions But here's the description from from the Opus Tex textbook, which I think is okay So here we have an important principle figure ground segmentation So if you look at this video or video this picture I think to me the dominant percept is that I see two faces that are looking at each other, right? So to me the dark the dark areas the black areas are two faces and the noses are facing each other like this to me That's the dominant percept But I can and if I see it like that the faces are to me the foreground and The white areas the background, but I can flip this around. It's by stable stimulus I can also focus on the white on the white area and I can tell myself. Oh, that's actually a vase And if I do that the vase becomes the foreground and then the black area becomes the background and the and these the faces Disappear right so I can choose I can have my perception essentially switch between Seeing the faces and seeing the vase. This is again. I would say Nicely demonstrates the distinction between sensation right because the visual input that I sense is the same But my perception can switch based on whether I choose to see the vase as the foreground or the faces as the four foreground Now and this idea this this idea that we automatically parse the world into a foreground and a background Is the principle of figure ground segmentation and I think it makes a lot of sense, right? Clearly clearly that's what we are doing now if you're looking at my face now For example, obviously you're seeing my face as the foreground and all the little bit of noise that you see in the background You see that as the background, right? It's too trivial to say because you have automatically made this segmentation But in into a factor foreground and a background and actually all all the gestalt principles are so simple Which makes them kind of trivial in a way, but still very interesting Here we have the principle of proximity what the principle of proximity says is that we consider things that are near each other To be part of the same object, right? So if we look at the thing a then I think you would say well that is a grid of six by six is thirty six dots If you look at B if you're a very autistic person You might still insist that that's a grid of six by six is thirty six dots But I think most people would be inclined to first perceive it as three vertical bars, right? and why well simply because These these dots are closer to each other than these dots, right? So we tend to group this together as one bar this together as another bar and this together as another bar Right, which is not to say that we cannot distinguish also the little circles that make up the bars It's just that we have a have a perception of seeing three separate bars here Then we have a quite related principles principle of similarity So if things are similar we tend to group them together So again here we have a grid you could say is a grid of six by six dots But most people would not say that the dominant perception here is that we essentially have six objects, right? We have a line that goes like this line that goes like this The up up and up and up so we tend to group the dots with the same color together because they are similar Right again, we of course we can we can see that this line of dots is made up of individual dots That's not a problem. It's just that we or there was no problem whatsoever It's just that we tend to group these six dots together into into the percept of line because they have the same color That's the principle of similarity Then we have the principle of good continuity So here if we see a stimulus like this Then you are very inclined to see this as a line that goes like this a smooth line and another line That goes like this another smooth line. You might also perhaps see it as a cross, right? But no one would see this as one line that goes like this Another line that goes like this right our perception really resists to that interpretation even though it's in principle a valid interpretation Right, but we strongly vastly prefer to see continuous lines We see prefer to see continuous shapes, and that's the principle of good continuity, right? Whenever we we can make sense of all the visual of all the visual information that we sense in such a way that That that there are continuous lines and smooth shapes, then that's what we do. We prefer good continuity Then we have the principle of closure Now that principle simply holds that if we see a stimulus like these two for example this circle Right the fact that I'm referring to it as a circle and you understand what I mean already illustrates the concept of closure because this is not a circle It is a collection of individual line segments, but the line segments are ins are oriented in such a way It's related to the principle of good continuity I would say that we prefer to see this we kind of fill up it perceptually fill up the missing parts and Perceived prefer to see it as a continuous circle, right? And this for example makes perfect sense imagine that you are looking through through a tree at a building That's behind a tree then the tree would block out little parts of the building, right? It would the leaves of the tree and with the branches of the tree would block out parts of the building But we we still perceive the building as being there as a whole, right? So we kind of through the principle of closure We kind of fill the gaps that the tree the branches and leaves of the tree make in our perception and The same the same principle of course holds for the rectangle here that we see on the right All right, so we whenever our perception can we automatically fill in the gaps or gaps that we have in our perception Okay, now with that let's move on to the to the next video video 3.5 We were going to take a look at the different sense namely hearing