Memory- the WMM Baddeley and Hitch

What is the Working Memory Model (WMM)?

The WMM explains short-term memory as an active, multi-component system that temporarily holds and manipulates information.

Developed by: Baddeley & Hitch (1974)Contrasts with: The unitary view of STM in the Multi-Store Model

Components:

Central Executive

Phonological Loop

Visuo-Spatial Sketchpad

Episodic Buffer (added in 2000)

What is the Central Executive?

Directs attention and coordinates the three slave systems

Has limited capacity

Does not store information

Involved in task switching and decision-making

Criticism:

Poorly understood and vague

Difficult to study directly → lacks falsifiability

What is the Phonological Loop?

Function:

Processes auditory and verbal information

Subcomponents:

Primary Acoustic Store: stores heard words for 1-2 seconds

Articulatory Process: allows for subvocal rehearsal

Research:

Explains the word length effect (short words recalled better than long ones)

Evidence from reading → subvocal rehearsal shows active processing

What is the Visuo-Spatial Sketchpad?

Function:

Processes visual and spatial information

Used for mental imagery (e.g. remembering a route)

Subcomponents:

Visual Cache: stores visual data

Inner Scribe: records spatial/movement data

Capacity: ~4-5 chunks (Baddeley, 2003)

What is the Episodic Buffer?

Added by: Baddeley (2000)

Function:

Acts as a multi-modal store

Integrates information from the phonological loop, visuo-spatial sketchpad, and LTM

Allows chunking of information and links to long-term memory

Helps recall complete episodic events

Supporting Evidence - Patient KF

Case Study:

Brain damage impaired verbal STM but not visual STM

Suggests STM has separate components

Supports the multi-component view of WMM

Limitation:

Case studies = unique individuals

May lack generalisability

Often no pre-injury memory baseline

Supporting Evidence - Dual Task Studies

Gathercole & Baddeley:

Participants performed two simultaneous tasks

If both used same component (e.g. two visual tasks), performance decreased

If tasks used different components (e.g. one verbal, one visual), performance improvedConclusion: Supports separate and limited-capacity systems

Supporting Evidence - Brain Imaging

Findings:

Phonological tasks → temporal lobe activation

Visuo-spatial tasks → occipital lobe activation

Conclusion:Different components of WMM activate different brain regions, providing biological support

Evaluation - Strengths of the WMM

✅ More detailed than the MSM - explains STM as active, not passive

✅ Case studies and dual task experiments support separate systems

✅ Neuroimaging evidence backs up component separation

✅ Real-world applications (e.g. understanding dyslexia, multitasking limits)

Evaluation - Weaknesses of the WMM

❌ Central executive is vague and untestable - may not be a single system

❌ Low ecological validity - much research done in artificial lab conditions

❌ Limited explanation for how information is transferred to LTM

❌ Case studies (e.g. KF) may not be generalisable to the wider population