Multi-Store Model Components

The multi-store model of memory consists of three main components:

1. Sensory Register (SR)

   • Unlimited capacity
   • Duration less than 1 second
   • Specific encoding modality

2. Short-Term Memory (STM)

   • Capacity of 7±2 items
   • Duration of 18-30 seconds
   • Auditory and semantic encoding

3. Long-Term Memory (LTM)

   • Unlimited capacity
   • Unlimited duration
   • Various encoding types

Highlight: The transfer of information from STM to LTM occurs through the process of rehearsal.

Vocabulary: Rehearsal - The process of repeating information to maintain it in short-term memory or transfer it to long-term memory.

Multi-Store Model Research

Murdock's Study (Multiple Stores)

Murdock's research provided evidence for separate memory stores:

• Participants learned word lists and then performed free recall
• Results showed the serial position effect:
  • Better recall of words from the beginning (primacy effect) and end (recency effect) of the list
• This supports the existence of separate short-term and long-term memory stores

HM Case Study (Multiple Stores)

The case of patient HM provided further evidence for separate memory stores:

• HM underwent surgery for epilepsy, which damaged part of his hippocampus
• His short-term memory remained normal, but he couldn't transfer new information to long-term memory
• This supports the idea of distinct short-term and long-term memory systems

Example: HM could remember recent conversations but couldn't form new long-term memories, such as learning the names of new people he met after the surgery.

Multi-Store Model Research (Continued)

Baddeley's Study (Coding)

Baddeley's research investigated the encoding of information in different memory stores:

• Participants learned four sets of words
• One group recalled immediately, another after 20 minutes
• Words were either acoustically or semantically similar/dissimilar
• Results:
  • Immediate recall: Better for acoustically dissimilar words
  • Delayed recall: Better for semantically dissimilar words
• This supports different encoding methods in short-term and long-term memory

Peterson and Peterson's Study (Duration)

This study examined the duration of short-term memory:

• Participants learned consonant trigrams and counted backward before recall
• Results:
  • After 3 seconds: 80% correctly recalled
  • After 6 seconds: 50% correctly recalled
  • After 18+ seconds: 10% correctly recalled
• Conclusion: Information in short-term memory decays if not rehearsed

Definition: Consonant trigram - A set of three consonant letters used as a memory task, e.g., "XKQ".

Multi-Store Model Evaluation

The multi-store model has both strengths and limitations:

Strengths:

• Supported by research evidence (e.g., Murdock, Baddeley, HM case study)
• Provides a simple framework for understanding memory processes

Limitations:

• Lacks ecological validity: Tasks don't represent daily life (e.g., nonsense syllables, word lists)
• Oversimplifies memory:
  • STM is more complex (Working Memory Model)
  • LTM has different types (episodic, semantic, procedural)
• Overemphasizes rehearsal: Doesn't distinguish between maintenance and elaborative rehearsal

Highlight: The multi-store model's simplicity is both a strength and a weakness, as it provides a clear framework but may oversimplify complex memory processes.

Forgetting: Interference Theory

Interference theory explains forgetting as a result of competing information. There are two types:

1. Proactive Interference:

   • Old learning affects recall of new information
   • Example: Learning Spanish interferes with learning French later

2. Retroactive Interference:

   • New learning affects recall of old information
   • Example: Learning French interferes with recalling previously learned Spanish

Example: A student who learned Spanish in high school might struggle with French vocabulary in college due to proactive interference from their Spanish knowledge.

Forgetting: Interference Research

Underwood's Study

Underwood analyzed findings from multiple studies:

• Concluded that words learned later in a series are not known as well as those learned earlier
• When memorizing multiple lists, recall after 24 hours was 20% for later lists compared to 70% for a single list

McGeoch and McDonald's Study

This study investigated the effect of different types of interfering material:

• Participants learned a list of 10 words to 100% accuracy
• They then learned a new list: synonyms, antonyms, unrelated words, nonsense syllables, 3-digit numbers, or no new list
• When recalling the first list, accuracy depended on the nature of the second list
• Synonyms showed the worst recall at 12.5%

Highlight: These studies provide evidence for both proactive and retroactive interference in memory.

Forgetting: Interference Evaluation

Strengths:

• Supported by research evidence (e.g., McGeoch & McDonald, Underwood)
• Has real-world applications, such as helping students plan revision

Limitations:

• Lacks external validity: Most studies conducted in laboratory settings
• Time between learning sets in studies may be unrealistically close

Additional points:

• Field experiments provide supporting evidence (e.g., Baddeley's study on rugby players)
• Interference effects can be overcome using cues (Tulving's research)

Quote: "Interference theory helps explain why students might confuse similar topics when studying multiple subjects intensively."

Forgetting: Retrieval Failure Theory

Retrieval failure theory suggests that forgetting occurs due to the absence of appropriate cues:

1. Internal cues $state-dependent forgetting$:

   • Related to mood or intoxication

2. External cues $context-dependent forgetting$:

   • Related to the environment

Encoding Specificity Principle:

• If cues available at encoding and retrieval are different, forgetting is more likely to occur

Definition: Encoding Specificity Principle - The idea that memory retrieval is most effective when the cues present during encoding are also present during retrieval.

Forgetting: Retrieval Failure Research

Godden and Baddeley's Study (Context)

This study investigated context-dependent forgetting:

• Four groups: learn in sea/recall on land, learn and recall on land, learn on land/recall in sea, learn and recall in sea
• Results: More words correctly recalled when learning and recall settings were the same

Carter and Cassaday's Study (State)

This study examined state-dependent forgetting:

• Some participants given antihistamine with mild sedative effect
• Four groups: learn and recall on drug, learn on drug/recall off drug, learn and recall off drug, learn off drug/recall on drug
• Results: Mismatch in state between learning and recall worsened performance on memory test

Highlight: These studies demonstrate the importance of both environmental context and internal state in memory retrieval.

Forgetting: Retrieval Failure Evaluation

Strengths:

• Supported by research evidence (e.g., Godden & Baddeley, Carter & Cassaday)
• Has practical applications, such as the cognitive interview technique used in forensic settings

Limitations:

• Recognition tasks can overcome context effects
• Context effects in real life may not be as extreme as in studies
• The encoding specificity principle may involve circular reasoning

Example: The cognitive interview technique used by police incorporates principles from retrieval failure theory to improve eyewitness recall.