 Hi, and welcome back to this video course on biological psychology. In this video, video 4.3, we're going to take a look at one type of memory, namely sensory memory. So everything that we perceive, right, everything that we see or that we hear or feel is very briefly represented in our sensory brain areas, right, the brain areas that we looked at during the perception section. So if you visually see something, this briefly triggers some kind of activity in your occipital, the visual brain areas of your occipital cortex, right, your primary visual cortex. Now, and this is essentially sensory memory. So this brief sensory trace that anything that you perceive sort of imprints on your brain and Sensory memory has a very high capacity meaning that essentially everything that you see causes a sensory memory. So in that sense, you have a memory of everything, you could say, but it is hardly real memory in the way that most people think about memory because it fades really quickly, within about one second. And as soon as you perceive something new, all that sensory memory is overwritten, right? So if I see a screen in front of me with let's say 20 digits, all those 20 digits form a very brief sensory memory. But then if I see another screen with another 20 digits, that earlier sensory memory will be erased in one go and I have a new sensory memory of those new 20 digits, right? So it is a form of memory of sorts, but it is very fragile, very short-lasting and is immediately erased by any new information that comes in. Now, when you talk about sensory memory in the context of vision, so visual sensory memory, then we generally use the term iconic memory. And iconic memory is by far the most studied form of sensory memory. And it was especially in the name George Sterling is important here, because he did a lot of research on iconic memory in the 1960s. And he used, among other things, of course, a very famous paradigm called partial report paradigm. Now, and the way that works, it's very simple. He basically presented a number of letters to the participant. So for example here, he might present, for example, an R, an N, and an F. And then very quickly, after the letters had been removed from the display, he would present, for example, a line at the location where the F was, and then he would ask the participant to report the letter that was present there, right? So the participant would say, okay, that's an F. Now, if there are only three letters, basically most people can do this perfectly, right? But if you have, for example, here in this case, we have three by four is 12 letters. If you then do that, it becomes very, very difficult, right? If you flash this on the screen and then you wait for a little while and then you put a line under where the F was, then very few people will be able to remember that there was an F here. But what he found is that if you present this line segment immediately after the presentation of these 12 letters, so if you really do 12 letters, up Q, right, the Q being the line segment, then participants are actually very good at remembering, at recalling the letter that was present there, because in that case, they can use their sensory memory, right? So the idea is that as soon as you see those 12 letters, all those 12 letters form a sensory memory, but that sensory memory is very short-lasting. It fades in about one second. But if you present a Q, so the line segment under one of the letters, within that one second, then people are actually able to report which letter was present, right, showing that we have a form of sensory memory, which is a very high capacity, but lasts only for a very brief period. With that, let's move on to the next video in which we're going to talk about working memory.