Transcription
[Music] welcome to siteboost. In this video, we're going to discuss another model of memory. This is called the working model of memory. It's effectively an improved version of what we called the short-term memory store in the multi-store model video. And in that video, we said that the model was a little too simplistic. With working memory model, we'll be able to explain how our brain is able to hold and work on both auditory and visual information in short-term memory.
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Differences between short-term memory and the working memory model. So the working memory model. Now, if you started A-level psychology with the memory unit, these models of memory can seem a little complex for a new A-level student. But I'd say if you learn to draw them from memory, that can really help you remember how they work and remind you of the studies that support them. So hopefully you can draw out the multi-store model of memory. It looks like this. And in our discussion of the multi-store model, we covered the short-term memory store. Well, researchers Baddeley and Hitch had some criticisms of the short-term memory store. Firstly, that short-term memory clearly isn't unitary. It's not just one single process. It's not a stopping-off station for information between the sensory register and long-term memory. Also, they thought that rather than a passive store just holding on to information and passing on to long-term memory, we use short-term memory to process or work on and combine multiple types of information. So we would describe working memory as an active processor. So those are two differences between the short-term memory store in the multi-store model and the working memory model.
The working memory model. You can see here all the parts of the working memory model. Again, you need to be able to reproduce this model from memory and describe each of the components. The first component is the central executive. And this is the part of the model that pays attention to information from the sensors. It's known as the head of the model because it passes information onto and controls the other components that we're going to call subsystems: the visuospatial sketchpad, the phonological loop, and the episodic buffer. The central executive is very limited in how much information it can hold at any one time, and it can only hold on to one type of information at a time. But it can switch quickly between each type of information.
The phonological loop is one of the subsystems and is controlled by the central executive. It processes auditory information like sounds and words. We can break the phonological loop into two sections: the phonological store, that we can think of as the inner ear, it holds on to the words that you hear, and the articulatory process, the inner voice that you use for maintenance rehearsal. And when considering capacity, we can say the phonological loop has a capacity of how much you can say in two seconds.
The visuospatial sketchpad is another of the subsystems. And as the name suggests, it's responsible for processing visual and spatial information. It can be described as an inner eye. Again, we can say it's controlled by the central executive. And a researcher called Logie suggests that the VSS can be broken down into two processors: a visual cache, which is a passive store for forms and colour, and the inner scribe, which is an active store holding onto the relationship between objects in 3D space.
The final part of the model is the episodic buffer. This was added to the model by Baddeley in 2000 in response to criticism of the model that it couldn't fully explain how information was effectively combined from both visual, acoustic, and long-term memory stores. So the episodic buffer is where information is integrated and stored. And that's the working memory model.
Now, just something quick to point out. AQA has written something a little different between what we need to know for the multi-store model and working memory models. For the multi-store model of memory, it says the features of each store: coding, capacity, and duration. So we had to go into serious depth for each store so we could describe and evaluate each store on each of those factors. Fortunately, for the working memory model, the specification only says the features in the model: coding, capacity. So if we get a question about coding or capacity, we can use information and evidence from any component of the working memory model to answer that question.
As a reminder, then, we've already said that when it comes to coding, the phonological loop is acoustic, and the visuospatial sketchpad is visual. And when talking about capacity, the phonological loop is what can be said in two seconds, and the central executive is limited in capacity. According to a researcher called Cohen, it's four items plus or minus one.
Evaluating the working memory model. We're going to consider four studies of the working memory model: a dual task performance study that shows the separation between the slave systems, a case study that supports that finding, biological evidence for the existence of the episodic buffer, and evidence for the capacity of the phonological loop.
To help us understand dual task studies, have you ever thought about how you can focus on a drawing and talk to someone at the same time, but find it really difficult to focus on reading if someone's talking to you at the same time? In the first example, a central executive can help us perform both tasks by sending the visual information to the visual spatial sketchpad and the verbal information to the phonological loop. But in the second example, the phonological loop is overwhelmed because too much of the same type of information is pushed to it.
Let's start evaluations then with a dual task performance study. Baddeley asked participants performed two tasks: either two visual tasks, which were tracking moving lights and describing the angles of letter F, or performing a visual task and a verbal task. Participants performed much better when both the tasks were different. This suggests that the visual spatial sketchpad exists as a separate process from verbal processing, the phonological loop, and the VSS is limited in capacity.
The separation of the phonological loop and the visual spatial sketchpad can also be seen in a case study by Shallice and Warrington. This is a case study of a man known as KF. His short-term memory issues were caused by a brain injury, but he had selective impairments to a short-term memory store. Only his verbal short-term memory was affected. He had no problems with the functioning of his visual short-term memory. This suggests then that the phonological loop and visual spatial sketchpad exist as separate processes and they're located in different parts of the brain.
We have brain scanning evidence by Paquereau that seems to show the physical location of the episodic buffer in the brain using fMRI. The researcher gave participants tasks that had them holding equal amounts of verbal and spatial information in short-term memory. But in some of the trials, both the visual and spatial information was separated. But in other trials, the visual and verbal information was integrated. Now, importantly, the brain scanner showed more activation in an area of the brain called the prefrontal cortex when the information was integrated, and posterior regions of the brain when it wasn't integrated. This suggests that the episodic buffer exists and it has an identifiable location in the brain.
And a final quick study by Baddeley, which found that people could remember more short monosyllabic words like "bond" and "yield" than longer words like "opportunity." This is a demonstration of the word length effect. People can remember about two seconds' worth of verbal information, supporting the capacity of the phonological loop as two seconds.
Additional evaluations. Okay, with those evaluations, we should be able to provide evidence for the existence of the components of the working memory model and talk about capacity. But we do need to cover some additional evaluations on how we can criticize the working memory model and some of the research that supports it.
Firstly, the central executive. As I've explained the working memory model, that's the bit that might have seemed the least clearly defined. And psychologists have argued that it isn't a fully operationalized concept in the working memory system. It seems to act as a homunculus, a little man in the brain performing any function that isn't fully explained by the model. Baddeley accepts this criticism. In fact, the addition of the episodic buffer was to address some of the problems with the central executive, such as how information can be integrated. But Baddeley suggests that rather than seeing this as a problem, there are opportunities for future research in explaining the functions of the central executive.
We can positively criticize the working memory model, saying it does seem to be more accurate in describing our short-term memory than the short-term memory store, especially in describing it as an active processor. This has been influential. Psychologists will now often not use the term short-term memory but use the term working memory.
Now, one criticism that we'll use a few times in the memory unit is the reliance on laboratory studies. And while they do offer a good control over extraneous variables, giving them high internal validity, we can argue that there are problems applying the findings outside of the experiment. So there are problems with external validity. The tasks themselves are designed so that data can be collected, and this often makes the task very different from how we use memory in real life. They lack what's called mundane realism. Now, this means that the findings from memory studies collected in experimental situations may not be generalizable to how we actually use memory in our day-to-day life.
To understand my final evaluation, we need to understand the term inference. Cognitive psychologists can't directly observe the working model of memory. They observe behavior and make assumptions or inferences about the underlying processes that led to that behavior. These inferences are effectively educated guesses, and those guesses could be wrong. When applied to studies on working memory, researchers have used inferences. They could actually be a completely different set of processes that underpin memory that produce the same behaviors, meaning the working memory model is incorrect.
Okay, I've given you a lot to work with there, mostly because there's a lot that can be asked in questions on the working memory model. So I want to prepare you for every eventuality. But if you're feeling a little overwhelmed with all that, my advice, as with all my videos, is to pick the ideas and evaluations you're most comfortable with, and if asked a question, shape that knowledge the best you can to answer the questions set.
Now, have a go at this real exam question on the working memory model. If you're a Psych Boost patron at the New Orleans level and above, you can access a tutorial on Psycboost.com. In it, I'll talk you through a model answer for this question and some general tips. For everyone else, don't forget to subscribe. You don't want to miss videos released right up to your exams, and I'll see you in the next Psych Boost video. Explanations for forget you.