Citing research evidence, explain the components of working memory.

The Components of Working Memory

Baddeley and Hitch’s model initially proposed three main components, later expanded to include a fourth. These are the Phonological Loop, Visuospatial Sketchpad, Central Executive, and the Episodic Buffer.

1. The Phonological Loop

The phonological loop deals with auditory and verbal information. It consists of two subcomponents:

• Phonological Store: This acts as an inner ‘ear’, holding auditory information for a short period (around 1.5-2 seconds).
• Articulatory Control Process: This acts as an inner ‘voice’, rehearsing information in the phonological store to prevent decay.

Research Evidence: Baddeley’s (1966) study demonstrated that participants had difficulty recalling sequences of consonants when presented rapidly, due to the limited capacity and duration of the phonological store. Furthermore, articulatory suppression (repeating ‘the’ silently) impaired recall, supporting the role of the articulatory control process. Word length effect – shorter words are remembered better than longer words – also supports this component.

2. The Visuospatial Sketchpad

The visuospatial sketchpad processes visual and spatial information. It is responsible for manipulating mental images and maintaining information about visual location and movement.

Research Evidence: Logie (1996) further divided the visuospatial sketchpad into two subcomponents: the visual cache (stores visual form and color) and the inner scribe (processes spatial and movement information). Studies involving tasks like mental rotation (Shepard & Metzler, 1971) demonstrate the capacity limitations of this system. Participants take longer to mentally rotate objects by larger angles, indicating active processing within the sketchpad.

3. The Central Executive

The central executive is the attentional control system of working memory. It is responsible for coordinating the activities of the phonological loop, visuospatial sketchpad, and episodic buffer. It also deals with selective attention, inhibition, and task switching.

Research Evidence: The central executive is the least understood component. Studies using dual-task paradigms, where participants perform two tasks simultaneously, demonstrate the central executive’s role in allocating attentional resources. For example, performing a verbal task while simultaneously performing a visual task requires central executive involvement. Norman & Shallice’s (1986) Supervisory Attentional System (SAS) model provides a framework for understanding the central executive’s functions.

4. The Episodic Buffer

Added to the model in 2000, the episodic buffer is a limited-capacity system that integrates information from the phonological loop, visuospatial sketchpad, and long-term memory into a coherent episodic representation. It acts as a temporary storage space for binding together different types of information.

Research Evidence: The episodic buffer was proposed to explain how working memory can hold and manipulate complex information that goes beyond the capacity of the phonological loop and visuospatial sketchpad. Evidence comes from studies showing that working memory performance improves when information is linked to prior knowledge or personal experiences.

Component	Function	Subcomponents	Supporting Evidence
Phonological Loop	Processes auditory/verbal information	Phonological Store, Articulatory Control Process	Baddeley (1966) – consonant recall; Word Length Effect
Visuospatial Sketchpad	Processes visual/spatial information	Visual Cache, Inner Scribe	Shepard & Metzler (1971) – Mental Rotation
Central Executive	Attentional control; coordination	None (supervisory system)	Dual-task paradigms; Norman & Shallice (1986) SAS model
Episodic Buffer	Integrates information from WM & LTM	None	Studies showing improved WM with prior knowledge