The Working Memory Model (Baddeley and Hitch, 1974)- A Simple Summary

Travis DixonCognitive Psychology

The working memory model explains how short-term memories work.

At first glance the working memory model can be very complicated and overwhelming. This post will break it down into four simple steps so you can understand it.

  1. Step One: What is “working memory?”
  2. Step Two: What are the “slave systems?”
  3. Step Three: What is the “central executive?” 
  4. Step Four: What is the “episodic buffer?”

The Working Memory Model

File:Baddley's Model of Working Memory.png - Wikimedia Commons

Don’t be intimated by the complicated sounding names. They’re quite easy to understand if you try hard enough.

1. What is “working memory”?

The working memory model is an explanation for how short-term memory works. Working memory is another name for short-term memory – the stuff you’re thinking about right now. There are two main types of working memory: visual and auditory. We can imagine how things look in our mind using visual working memory. We can remember words, language and sounds using auditory working memory.

You know when you get a song stuck in your head and it can’t get out? That’s auditory working memory. Ever tried to remember where you left your phone by imagining all the places you’ve been? That’s visual working memory.

Alan Baddeley defines working memory as “…a brain system that provides temporary storage and manipulation of the information necessary for such complex cognitive tasks as language comprehension, learning, and reasoning.” (Baddeley, 1992) I like to define it as “the information held in our conscious attention.” 

2. What are the “slave systems?”

One important claim of the working memory model is that short-term memory has different parts for different types of memory (visual and auditory). That’s where the slave systems come in – they contain our visual and auditory working memory.

The slave systems have complicated names which sound scary at first but are easily understood when you think of how you use them.

  • The visuospatial sketchpad: this is the system that controls visual information.
  • The phonological loop: the system that controls auditory information.

We use our visuospatial sketchpad for visual and spatial information. Visual working memory is remembering what things look like, such as trying to remember someone’s face or drawing an animal. Spatial working memory is remembering where things are, like trying to remember how to get to a new place. If you can imagine your journey to school, the things you see on the journey (e.g. roads, houses, landmarks) are using the visual part and remembering which road goes where and what path to take is the spatial part of the visuospatial sketchpad.

The phonological loop (originally called the articulatory loop) is for auditory information. It’s really useful for learning languages, especially a second language. Any time you’re trying to remember verbal (words) or sounds you’re using your phonological loop.

Why are they called slave systems? Because they are controlled by a boss (the central executive) and they have the basic function of storing information.

3. What is the “central executive?”

We can control what we think about. Let’s demonstrate: Picture an orange. Now give it eyes, arms and legs. Now imagine that orange with a microphone singing “Happy Birthday.” The central executive was responsible for bringing in those different images and sounds into your short-term memory. It’s described as “the little boss in the head” because it controls the slave systems and operates your working memory.

The central executive has numerous functions. In the original model, it was “…assumed to be capable of attentional focus, storage and decision making,” (Baddeley, 2011). For simplicity’s sake we’ll focus on the two most important (and easily understood) functions of the central executive:

  1. Controlling the slave systems
  2. Attentional focus (aka selective attention)

Controlling slave systems: We have all our long-term memories stored. When we start thinking about them, it’s the central executive that brings that directs the slave systems to bring those memories into our current thoughts. Ever tried to remember someone’s name? That’s the central executive searching your long-term memory. Similarly, if you’ve ever tried to memorise something, like a phone number, and you are constantly rehearsing that information in your phonological loop, it’s the central executive sending that instruction to the phonological loop to repeat – repeat – repeat.

Selective attention: Ever tried studying in a noisy classroom? That cognitive effort you exert trying to block out distractions and focus on your work is your central executive working hard to focus the attention on the information that matters most. This ability to block out distractions and focus attention on the relevant information is a key job of the central executive.

If you think of working memory as simply “thinking” it can make it easier to understand. Pedantic cognitive psychologists might disagree, but what is our working memory if not our current thoughts?  

5. What is the “episodic buffer?”

The original model only had the central executive and slave systems. Critics pointed out a few memory capabilities that the model couldn’t explain. For example, the slave systems account for sight and sound, but what about our other senses? Also, some people seem to be able to hold massive amounts of information in their minds, like actors who can recite entire pages of Shakespeare or storytellers who recall epic poems word for word. If short-term memory is so limited, where is this information being kept?

These are some of the reasons why Baddeley and Hitch introduced the “episodic buffer.” This is a temporary store of information, like a holding cell (or buffer) between long-term and short-term memory. It holds information until it’s needed.

The episodic buffer is “…capable of holding multidimensional episodes or chunks, which may combine visual and auditory information possibly also with smell and taste. (Baddeley, 2010 Link)

Check Yourself: Do you get it?

Whether writing an essay or studying for a test, to give an accurate summary of the working memory model you should be able to accurately and succinctly do the following:

  • Diagram the model from memory with accurate labels
  • Define working memory
  • Explain the functions of the central executive, the slave systems and the episodic buffer

Who cares?

In my mind, more important than knowing the model is comprehending the idea of working memory and realising how important it is in your daily life. Once you can understand that, you then become aware of all the distractions and demands placed on your working memory, like smartphones. My working memory is my most valuable intellectual asset, which is why I try to protect it.


Baddeley A. (1992). Working memory. Science (New York, N.Y.)255(5044), 556–559. (Link)
Baddeley, A. D., Allen, R. J., & Hitch, G. J. (2011). Binding in visual working memory: the role of the episodic buffer. Neuropsychologia49(6), 1393–1400. (Link)
Baddeley, A. (2010). Working memory. Current Biology, 20(4), R136–R140. doi:10.1016/j.cub.2009.12.014b (Link)

Caplan, D., Waters, G., & Howard, D. (2012). Slave systems in verbal short-term memory. Aphasiology26(3-4), 10.1080/02687038.2011.642795. (Link)