Psych Boost: Memory Unit

Overview

• The memory unit consists of six videos covering:
  • Two models of memory
  • Types of long-term memory
  • Reasons for forgetting
  • Issues with eyewitness testimony
  • Methods to improve eyewitness testimony
• The topics are rooted in the cognitive approach in psychology.

Multi-Store Model (MSM)

Introduction

• Created by Atkinson and Shiffrin (1968)
• Linear information processor model
• Consists of three passive stores:
  • Sensory Register
  • Short-Term Memory (STM)
  • Long-Term Memory (LTM)
• Key features of each store:
  • Coding: Format of stored information
  • Capacity: Amount of information stored
  • Duration: Length of time information is held

Sensory Register

• Directly receives sensory information
• Coding is modality-specific (different for each sense)
• Capacity: Very large, potentially unlimited
• Duration: Very short (~250 milliseconds)
• Information moves to STM through attention
• Unattended information is lost

Short-Term Memory (STM)

• Coding: Acoustic (information as sound)
• Capacity: 7 ± 2 items
• Duration: 18 to 30 seconds
• Information is maintained by rehearsal
• Types of rehearsal:
  • Maintenance: Repetition to keep in STM
  • Elaborative: Linking new info to existing LTM
• Information not transferred to LTM is lost due to displacement or decay

Long-Term Memory (LTM)

• Coding: Semantic (meaningful connections)
• Capacity: Very large, potentially unlimited
• Duration: Very large, potentially unlimited
• Information may not be truly lost but may be inaccessible without the right cue

Evaluations of the Multi-Store Model

Supporting Research

1. Glanzer and Cunitz (1966)
   • Primacy-Recency effect: Shows separate processes for STM and LTM.
2. Sperling’s Study
   • Sensory Register Capacity: Large capacity demonstrated by recalling letters from a grid.
3. Baddeley’s Study
   • Coding: Different for STM (acoustic) and LTM (semantic).
4. Jacobs’ Study
   • STM Capacity: 7 ± 2 items, demonstrated using recall of numbers and letters.
5. Peterson and Peterson’s Study
   • STM Duration: Demonstrated using trigram recall and interference task.
6. Wagenaar’s Diary Study
   • LTM Capacity and Duration: Very large, shown through long-term recall of personal events.
7. Bahrick’s Study
   • LTM Duration: Demonstrated through recall of school friends’ photographs.

Criticisms and Limitations

• Artificiality of experimental settings and tasks (lack of ecological validity and mundane realism)
• Research may not reflect everyday memory usage
• Inferences required due to indirect observation of memory processes
• Evolutionary support for large capacity and short duration of sensory register
• Simplistic Nature of MSM:
  • Assumes unitary and passive stores
  • Oversimplifies complexity of STM and LTM, which have multiple components
  • Lacks face validity (e.g., STM capacity varies with age and practice)

Exam Practice

• Real exam questions and model answers are available for patrons at the Neuron level and above on psycboost.com.

Conclusion

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• Next video topic: Types of Long-Term Memory