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Current time:0:00Total duration:4:27

Video transcript

let's look at the difference between top-down and bottom-up processing so what is bottom-up processing bottom-up processing basically begins with the stimulus so let's imagine that we're looking at something or let's say I'm looking at a banana the banana is sitting there and it influences what we perceive so stimulus stimulus influences what we perceive our perception so if I know absolutely nothing about something then the stimulus or whatever it is that I'm looking at yet I don't know anything about I've never seen it I don't have any preconceived cognitive constructs about what it is I'm looking at the stimulus basically is influencing my perception so for example let's imagine that I'm looking at a cockpit of a plane I'm not a pilot so I'm not really too familiar with everything and everything kind of looks fairly confusing um so basically all the different stimuli so this stimulus you know a bunch of gauges and this rudder looking thing I'm basically looking at all the different little parts of something that is new and novel to me and trying to kind of comprehend what it is that I'm looking at so this is bottom-up this is when you start with no preconceived idea of what it is that you're looking at and allow the stimulus to influence your perception of what it is that you're looking at so bottom-up processing is data-driven and your perception of what it is that you're looking at directs your cognitive awareness of the object so in contrast top-down processing basically uses your background knowledge so uses your background knowledge to influence perception so let's look at this example over here so what we're actually seeing are a bunch of circles they're just a bunch of circles and then inside the circle there is a they're a couple of lines drawn so we're looking at this set of circles these white circles with lines drawn and set inside of them we're creating this this cube we're basically taking these lines and then putting them together in order to create a cube even though the stimulus itself which is the circles with the lines actually doesn't draw a cube because there are these black spaces over here and there's absolutely nothing in the black spaces but our brains are basically taking this information and using our knowledge of cubes and what they're supposed to look like we're recreating a cube despite a lack of a cube actually being present in the image so that's top-down processing is using your background information your background knowledge your learning your expectations in order to influence what it is that we're perceiving so in other words it's Theory driven we look at this and we assume that they're trying to represent a cube even though one is not actually drawn there and we're using that theory in order to shape our cognitive understanding of what it is that we're looking at so our perception our behavior is influenced by our expectations which is top-down processing so we're using what's already in our heads in order to perceive what it is that we're looking at whereas in bottom-up processing we're using the stimulus itself in order to drive our perception so another good example of top-down processing would be Where's Waldo so in Where's Waldo we have a mental idea of what we're trying to do which is to find Waldo amidst this really jumbled mess of a picture so if we were using bottom-up processing in order to look at this we would just be seeing a whole bunch of little people and we wouldn't really be goal driven we wouldn't be trying to do anything but would top-down processing we have a goal and we're able to look through here to find Waldo