Memory: The Working Memory Model

Another day, another post.  Actually, I might schedule this post for tomorrow.  I think it makes more sense to have both models on both days.  So, uh… three posts in a day!  Wow!

The Working Memory Model is supposedly a new and improved Multi-Store Memory Model, but the two are completely different.  For one, there are more parts in the Working Memory Model.  Here’s a list of them:  Central Executive, Episodic Buffer, Visuo-Spatial Sketchpad, Phonological Loop, and Long-Term Memory.  The Visuo-Spatial Sketchpad also contains a visual cache and an inner scribe, whilst the phonological loop contains a phonological store and an articulatory process.  Lots of parts, lots of words.  Don’t worry – I’m about to go through them.  All will be fine.

Let’s start at the beginning (a very good place to start).  The Central Executive is kind of like the big boss of the Working Memory Model.  It’s mostly involved with decision-making and critical thinking.  It makes sure that the entire system carries on running smoothly, and takes over when something goes wrong.  Sometimes, it’s analogised as being like the Fat Controller in Thomas the Tank Engine, if that helps you at all with remembering it.

This being said, the definition we’ve been given of the Central Executive system is vague – like the Episodic Buffer below, nobody is quite sure exactly what it does.  Furthermore, critics believe that there must be more than one branch of the Central Executive system – one brain-damaged patient, EVR, had good reasoning skills but poor decision-making skills, which suggests that the Central Executive as a whole could not have been damaged, or both would be affected.  Essentially, the Central Executive system is too vague in its current form.

Next, you have the Episodic Buffer.  The Episodic Buffer was actually added later in response to criticisms, and it’s supposed to act as a point of transmission between the Long-Term Memory and the Central Executive Memory.  You’ll notice that this explanation is very short; that’s because nobody really knows what the episodic buffer is, or what it does.  That’s one of the main criticisms of the Working Memory Model.

Branching off from the Central Executive, you have the Visuo-Spatial Sketchpad and the Phonological Loop.  I’ll start with the Visuo-Spatial Sketchpad.  The Visuo-Spatial Sketchpad is the part of the memory concerned with visual information: it helps us to remember what things look like – their properties, such as colour – and also where they are in relation to each other.  Those things are actually covered by different areas of the Visuo-Spatial Sketchpad.  The visual cache is what stores the properties of individual objects – that’s things like shapes and colours – the basic information about individual pieces of information.  The inner scribe is what stores information about where different objects are in relation to each other – or, in shorter terms, spatial information about objects.

A patient called LH was better with spatial information than visual properties, which supports the idea that there are two branches of the Visuo-Spatial Sketchpad.

The Phonological Loop helps us deal with sound; that includes isolated sounds as well as verbal information.  It also helps to preserve the order of information, which means that information doesn’t get jumbled up in the brain.  Like the Visuo-Spatial Sketchpad, it’s split into two different parts: the phonological store and the articulatory process.  The phonological store holds information you hear directly – a little bit like the inner ear, but inside the brain.  The articulatory process processes information that you don’t hear directly, like words you read in your head.

A patient called KF is thought to have had damage to the Phonological Loop, as his short-term forgetting of verbal information was much greater than his forgetting of visual information.  However, he could recognise meaningful sounds, like a telephone ringing, but struggled with verbal material.  SC is also thought to have had damage to the phonological loop, as his learning abilities were generally good with the exception of him being unable to learn word pairs.

There are issues with using brain-damaged patients as a support, however, as most brain-damaged patients have also undergone some amount of trauma.  This means that the effects of brain damage are not isolated to physical damage to the brain, but also the psychological damage of undergoing trauma.

The Visuo-Spatial Sketchpad and Phonological Loop don’t have any direct connection to the Long-Term Memory.  Instead, all information passes back to the Central Executive, which filters through it, then transfers the information to the Long-Term Memory itself.

Some of our evidence for the Working Memory Model comes from dual task performance.  Dual task performance is based on the idea that if one part of the brain is performing a task, it won’t be able to perform a second task, but another part of the brain will be able to perform a task.  That isn’t worded very well, but if you’re listening to music and drawing, the drawing is concerned with the Visuo-Spatial Sketchpad and the music is concerned with the Phonological Loop, so you can do both.  This was demonstrated by Baddeley and Hitch, who used processes involving the Central Executive and the Articulatory Process, which had involvement from the Central Executive in one condition, to examine the effects of dual task performance.  The tasks were both quicker if the second task did not also involve the Central Executive.

That’s the Working Memory Model!  Next up, we’ll be going through the types of long-term memory.  I like that one – it means I get to crack out the analogies and anecdotes!

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