The Working Memory Model

Baddeley & Hitch (1974)

• Concept: Short-term memory (STM) is composed of multiple interacting components rather than a single store.
• Focus: The model explains STM only; long-term memory (LTM) is a passive repository accessed by STM when needed.
• Scope: Not a full model of memory, but a functional account of STM operations and their coordination.

Central Executive

• Role: An attention control system that monitors and coordinates the sub-systems for processing and storage.
• Functionality:
  • Acts as the system’s CEO, allocating resources and selecting strategies.
  • Focuses, divides, and switches attention across tasks.
  • Modality-free, handling auditory and visual inputs.
  • Limited capacity; cannot manage many concurrent demands.

Phonological Loop

• Capacity: Limited.

• Function:

  • Processes auditory information and language (spoken and written).
  • Subdivisions:
    • Phonological store: Holds auditory memory traces (words heard).
    • Articulatory control system (inner voice): Rehearses and maintains verbal information.

• Operation and implications:

  • Receives input from sensory memory (auditory), LTM (verbal), and the articulatory system.
  • Trace duration is brief (about 1.5–2 seconds) without rehearsal.
  • Performance depends on verbalization time; longer words are harder to maintain.
  • Supports everyday tasks that require holding verbal sequences (e.g., dialing a new number, repeating a foreign word, counting).

• Articulatory suppression:

  • Concurrent repetition (e.g., “1-2”) overloads rehearsal, reducing recall accuracy.
  • Disrupts tasks like serial recall and reading prose that rely on the phonological loop.

Visuo-Spatial Sketchpad

• Role: Temporary store for visual and spatial information (the “inner eye”).
• Function:
  • Stores and manipulates visual patterns and spatial movements in 2D/3D.
  • Supports navigation, locating objects, and visual imagery (e.g., where you left your phone).

Episodic Buffer

• Role: Temporary, limited-capacity buffer that integrates multiple sources.
• Function:
  • Binds auditory and visual inputs with LTM to support current tasks.
  • Acts as a passive display store (like a screen) for integrated content.
  • Proposed to underpin conscious awareness of combined information.

Supporting Studies

Landry & Bartling (2011)

• Aim: Test whether articulatory suppression affects serial recall of phonologically dissimilar letters.
• Sample and design: 34 undergraduate psychology students; independent samples (experimental vs control).
• Procedure:
  • Ten lists of seven dissimilar letters (F, K, L, M, R, X, Q).
  • Control: View list (5 s), wait (5 s), then write letters in order; repeated 10 times.
  • Experimental: Perform articulatory suppression (“1-2” at 2/s) during presentation and recall; repeated 10 times.
  • One practice list; accuracy scored only if letters were in the correct positions; mean percent correct computed.
• Findings:
  • Control mean = 76% (SD = 0.13); experimental mean = 45% (SD = 0.14).
  • T-test indicated a significant difference (p ≤ 0.01).
• Conclusion:
  • Articulatory suppression prevents rehearsal in the phonological loop due to overload, impairing serial recall.
  • Supports the model’s claim of a limited-capacity phonological loop and distinct STM sub-components.

Baddeley et al. (1975)

• Method:
  • Five list lengths (4–8 words); eight sequences per length for short words and eight for long words.
  • Within-subjects: All participants received both short and long word sets, with list lengths in ascending order.
  • Words presented at 1.5 s per item; 15 s to recall in order; prompt cards displayed pools to familiarize items.
  • Eight university students; testing discontinued when participants failed all eight sequences at a length.
• Findings:
  • Superior recall for short words across all sequence lengths for every participant.
  • Performance measured as fully correct sequences (items correct and in order).
• Conclusion:
  • Word length significantly affects memory span: shorter words yield higher span.
  • Consistent with a time-limited phonological loop that is constrained by articulation duration.

Evaluation of Studies

• Strengths:
  • High internal validity via controlled procedures and clear operationalization (e.g., fixed rates, list lengths).
  • Demonstrate the limited capacity and rehearsal dependency of the phonological loop.
  • Replicable designs support reliability and cumulative evidence for sub-unit functions.
• Weaknesses:
  • Artificial tasks reduce ecological validity; real-world multitasking involves richer cues.
  • Laboratory isolation of sub-systems may not reflect their integration in everyday contexts.

Overall Evaluation of the Working Memory Model

• Strengths:
  • Offers practical guidance: reduce competing input in the same modality; dual-tasking is easier across modalities.
  • Clinical relevance: episodic buffer–based techniques (e.g., cognitive stimulation) may aid memory support.
  • Clarifies how distinct codes (verbal vs visual) can be coordinated by the central executive.
• Weaknesses:
  • Heavy reliance on dual-task lab paradigms may limit real-world generalizability.
  • Some constructs (e.g., exact central executive mechanisms) remain underspecified.

LAQ Planning Notes

• Theory overview:
  • Define components, capacities, durations, and functions; note relevance to conscious processing via the episodic buffer.
• Evidence 1: Landry & Bartling (2011)
  • Shows articulatory suppression reduces accuracy by blocking rehearsal; emphasizes maintenance rehearsal’s role.
  • Supports strong construct validity through sub-system interference patterns.
  • Evaluate internal validity vs ecological validity.
• Evidence 2: Baddeley et al. (1975)
  • Demonstrates word length effect and limited phonological loop capacity across list lengths.
  • Discuss applicability to predicting recall based on item length and sequence size.
  • Evaluate scope and generalizability.
• TEACUP:
  • Testability, empirical support, applications, construct validity, usefulness, and predictive value.
• Conclusion:
  • Converging evidence supports a multi-component STM with limited, modality-specific stores coordinated by a central executive.