Baddeley's Working Memory Model & the Episodic Buffer

Instructor: Robin Harley

Robin has a PhD in health psychology. She has taught undergraduate and graduate psychology, health science, and health education.

Baddeley and Hitch defined working memory as a system that temporarily holds and manipulates information. This lesson will explore working memory and its subsystems, including the recent addition of the episodic buffer.

Working Memory Model

Have you ever repeated a phone number in your mind long enough to write it down, or recalled an image of your home's layout while shopping for furniture? It may seem simple, but it's actually a complex process. You've most likely heard of the distinction between 'short-term' vs. 'long-term' memory. In the late 1960s, Richard Atkinson and Richard Shiffrin used these terms to describe the different parts of our memory. The short-term component was thought to be a temporary storage space that could hold a small amount of information until it was forgotten or transferred to long-term storage. In addition, long-term storage only occurred if the information was rehearsed in the mind.

Other contemporary researchers found this model to be limited, particularly in its treatment of the short-term component of memory. In 1974, Alan Baddeley and Graham Hitch created a new model that expanded on this component significantly. Instead of a single short-term memory space, Baddeley and Hitch proposed a more complex 'working memory,' a system that temporarily holds and manipulates various kinds of information in specialized ways. Working memory consists of several components, called the central executive, the phonological loop, the visuospatial sketchpad, and the episodic buffer, which was added to the model in 2000. Let's discuss each of these components.

Central Executive

Like its name suggests, the central executive is in charge of the whole working memory system. It is considered the 'boss' that coordinates and delegates work to its subsystems, like the phonological loop and the visuospatial sketchpad. These are also called the slave systems. The central executive also plays a large role in controlling attentional resources. For example, imagine you are driving down a busy street while having an in-depth conversation with the passenger in your car. You notice that the car ahead of you is swerving and the driver appears to be intoxicated. You will most likely abandon your conversation and direct all or most of your attention toward avoiding the car. It is the central executive that decides which of these two things deserves your concentration.

Imagine the central executive as the boss of a company. The boss receives information from her assistants (the slave systems) and draws on the information she already has (long-term memory) to decide which strategies are best to deal with a problem. She can only handle a limited amount of work on her own, so she calls on her assistants for help. Now we will discuss these assistants, or slave systems, in more detail.

Phonological Loop

The phonological loop handles acoustic information, like speech and other sounds. It is further divided into two parts: the phonological store and the articulatory control process. The phonological store holds onto spoken words (and written words that are converted into speech) for a couple of seconds. The articulatory control process occurs when we mentally rehearse something using our 'inner voice.' For example, when someone tells you a phone number, the numbers enter the phonological store. Then you'd use the articulatory control process to repeat it to yourself until you can either write it down or commit it to long-term memory.

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