Memory Unit Overview

Introduction

• This unit consists of six videos exploring:
  • Different types of long-term memory
  • Reasons for forgetting
  • Problems with eyewitness testimony and improvements in police practices

Cognitive Approach

• Many topics in this unit stem from the cognitive approach in psychology.
• Recommended to watch related videos for deeper understanding.

Multi-Store Model

• Developed by Atkinson and Shiffrin (1968)
• Information Processor Model
  • Linear flow of information
  • Stores are passive (just hold information)

Stores in the Multi-Store Model

1. Sensory Register

   • Receives sensory information from the environment
   • Coding: Modality specific (different for each sense: iconic, auditory, haptic, gustatory, olfactory)
   • Capacity: Very large, potentially unlimited
   • Duration: ~250 milliseconds

2. Short-Term Memory (STM)

   • Information moves from sensory register via attention
   • Coding: Acoustic
   • Capacity: 7 items ± 2
   • Duration: 18-30 seconds
   • Maintenance Rehearsal: Repeating information to keep it in STM
   • Elaborative Rehearsal: Linking new info to existing long-term memory for transfer
   • Forgetting: Due to displacement or decay

3. Long-Term Memory (LTM)

   • Coding: Semantic (meaningful connections)
   • Capacity: Very large, potentially unlimited
   • Duration: Vast, but not well defined
   • Information might be inaccessible rather than lost

Summary Table of Multi-Store Model

Evaluation of Multi-Store Model

Research Evidence

• Primacy-Recency Effect (Glasner, 1966)
  • Participants remember first and last items better than middle ones, supporting separate processes for STM and LTM.

Sensory Register Capacity Study (Sperling)

• Flashed 20 letters for 1/20th of a second; participants recalled a row accurately.
• Suggests sensory memory has larger capacity than STM.

Short-Term Memory Coding Study (Baddeley)

• Participants recalled word lists with varying acoustic and semantic similarity.
• Acoustically similar words had worse recall, supporting the acoustic coding hypothesis.

Short-Term Memory Capacity Study (Jacobs)

• Participants recalled around 9 numbers and about 7 letters on average.

Short-Term Memory Duration Study (Peterson and Peterson)

• Found duration of STM to be 18-30 seconds using an interference task.

Long-Term Memory Evidence

• Baddeley’s study showed worse recall for semantically similar words after 20 minutes, supporting semantic coding.
• Studies by Wagner and Barrack showed high recall rates years after events, suggesting large capacity and duration for LTM.

Critiques of the Multi-Store Model

• Research often lacks ecological validity due to artificial lab settings.
• Tasks may lack mundane realism, affecting external validity.
• Experiments may oversimplify memory processes; multiple types of memory exist.
• Assumptions about fixed capacities and passive stores may not reflect actual memory functions.

Conclusion

• The multi-store model provides foundational understanding but has limitations.
• Further exploration of types of long-term memory in next videos.

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