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3.3 Memory models, MSM

Multi-Store Memory Model

  • Important theories of memory to be studied include:
    • Multi-store model of memory (MSM)
    • Working memory model
    • Long-term memory

Key Quote on Memory

  • "The true art of memory is the art of attention." - Samuel Johnson

Memory Testing Activity

  • Activity: Memorize a list of words in 2 minutes and then write them from memory within the next 2 minutes.
  • List of Words: Nine, Swap, Cell, Ring, Lust, Plugs, Lamp, Apple, Table, Sway, Army, Bank, Fire, Hold, Worm, Clock, Horse, Color, Baby, Sword, Desk, Grab, Find, Bird, Rock
  • Average Recall: 7 ± 2 items
  • Extraordinary Recall: Higher than average should be considered extraordinary.

General Memory Facts

  • The brain consists of about one billion neurons, each forming about 1,000 connections, totaling more than a trillion connections.
  • Estimated Memory Capacity: Paul Reber suggests it can store up to 2.5 petabytes.
  • Petabyte: Equivalent to 1,000,000 GB or 1,000 TB.
  • Misconceptions about other species’ memory abilities like that of Dory (Blue Tang fish) are exaggerated; they do not have poor memory compared to other fish.

The Multi-Store Model Theory

  • Originated in the 1950s and 1960s cognitive revolution, developed by Atkinson and Shiffrin (1968).
  • Introduced the concept of different memory stores:
    • Sensory Memory
    • Short-Term Memory (STM)
    • Long-Term Memory (LTM)

Memory Stores

Sensory Registers

  • Function: Store information from senses for a very brief period (~ 0.5 seconds).
  • Features:
    • Modality-specific storage (taste, sight, sound, etc.).
    • Stores a vast amount of information but decays rapidly.
    • Only a small proportion transfers to STM.

Short-Term Store (Working Memory)

  • Capacity: Limited to about 7 ± 2 units (Miller's magic number).
  • Duration: Information lasts 15 to 30 seconds without rehearsal.
  • Key Function: Acts as a rehearsal buffer; rehearsed information can transfer to LTM.
  • Diagram: Recommended to support written exam answers.

Long-Term Store

  • Characteristics: Holds long-term, permanent memories.
  • Capacity: Unlimited.
  • Storage Format: Memories are maintained as memory traces.

Attention and Rehearsal

  • Attention: Necessary for transferring information from sensory registers to STM.
  • Rehearsal: Essential for transferring information from STM to LTM.
    • More rehearsal strengthens the memory trace, leading to longer retention.

Search and Retrieval

  • Control Processes: Retrieval of information from STM and LTM involves searching processes.
  • Forgetting: Can occur not only from decay but also from search failures in locating memory traces.

Coding in Memory Stores

  • Short-Term Memory (STS): Primarily uses phonetic coding (e.g., repeating words aloud).
  • Long-Term Memory (LTM): Relies on semantic coding (understanding information and making meaningful connections).

Encoding Methods

  1. Visual Encoding: Superficial processing focused on appearance (e.g., remembering faces).
  2. Acoustic Encoding: Focus on sounds without meaningful connections (e.g., familiar melodies).
  3. Semantic Encoding: Understanding meaningful connections which enrich memory storage in LTM.

Brain Structures and Memory

  • Prefrontal Cortex: Associated with STM.
  • Hippocampus: Related to LTM consolidation.
  • Amygdala: Involved in emotional memory enhancement, boosting LTM transfer for emotionally charged experiences.

Key Study: Baddeley (1966)

Aim

  • Assess whether STM & LTM coding is primarily acoustic or semantic.

Procedure

  • Participants arranged words from 4 lists into correct order:
    • List A: Acoustically similar (cat, mat, sat)
    • List B: Acoustically dissimilar (pit, day, cow)
    • List C: Semantically similar (big, huge, tall)
    • List D: Semantically dissimilar (hot, safe)
  • STM test: Rearranging immediate recall; LTM: 20-minute delay with interference task.

Results

  • STM: List A performed worst (10% recall); Lists B, C, D performed 60-80% respectively.
  • LTM: List C performed worst (55% recall); others performed better (70-85%).

Conclusions

  • STM: Acoustic encoding due to confusion with similar-sounding words.
  • LTM: Semantic encoding because of confusion with similar-meaning words.

Key Study Evaluation: Baddeley (1966)

  • Generalization: Results applicability to wider population.
  • Reliability: Can the study be repeated with consistent results?
  • Ecological Validity: Does it reflect everyday behavior?
  • Ethics: Adherence to ethical guidelines.

Strengths

  • Aligns with real-life examples of memory use (grocery lists vs. literature).
  • Supported by extensive evidence for distinct STM and LTM.

Weaknesses

  • Simplistic view of memory; ignores complexity (e.g., types of LTM).
  • Challenges in accurately measuring LTM capacity.
  • Low ecological validity from artificial tasks in lab settings.