The Case Study of HM: Supporting the Multi-Store Model

The case of patient HM, studied by Milner, offers compelling support for the multi-store model of memory. This case study provides crucial insights into the separation of short-term and long-term memory stores.

Key Points:

• HM underwent surgery to remove his hippocampus, which severely impacted his ability to form new long-term memories.
• Despite the damage to long-term memory, HM's short-term memory remained largely intact.
• HM could not remember personal or public events that occurred after his surgery, demonstrating the impact on long-term memory formation.

Evaluation:

• The case supports the multi-store model's assumption of separate short-term and long-term memory stores.
• HM's ability to maintain information in short-term memory while being unable to form new long-term memories provides strong evidence for the distinction between these stores.
• The study demonstrates that damage to one memory store $long-term memory$ does not necessarily affect the functioning of another $short-term memory$.

Example: HM could not remember the death of his parents or major historical events like the Vietnam War, yet he could recall information presented to him immediately, showing intact short-term memory.

Highlight: This case study is particularly significant as it provides real-world evidence for the theoretical model, demonstrating how brain damage can selectively impact different memory stores.

Baddeley's Research on Memory Coding

Baddeley's study on memory coding provides further support for the multi-store model of memory by demonstrating differences in how information is encoded in short-term memory (STM) and long-term memory (LTM).

Key Findings:

• Short-term memory primarily uses acoustic coding (based on sound).
• Long-term memory primarily uses semantic coding (based on meaning).

Vocabulary:

• Acoustic coding: Encoding information based on how it sounds.
• Semantic coding: Encoding information based on its meaning.

Evaluation:

• This research supports the multi-store model by showing that STM and LTM use different coding methods.
• The distinct encoding processes provide evidence that STM and LTM are separate and independent stores.
• If STM and LTM were part of the same system, we would expect similar coding methods, but Baddeley's research shows this is not the case.

Example: In STM, words that sound similar (like "cat" and "mat") are more likely to be confused, while in LTM, words with similar meanings (like "happy" and "joyful") are more likely to be confused.

This study strengthens the multi-store model's assumption that short-term and long-term memory are distinct systems with different characteristics and processes.

Sperling's Study on Sensory Memory

Sperling's research provides crucial evidence for the existence of sensory memory, supporting the multi-store model of memory (MSM) by demonstrating the characteristics of the sensory store.

Procedure:

• Participants viewed a screen where rows of letters were flashed very briefly $1/20th of a second$.
• After the screen went blank, participants were asked to recall as many letters as possible.

Key Findings:

• Information in the sensory store decays very rapidly, typically within less than half a second.

Evaluation:

• This study supports the MSM by providing evidence for a distinct sensory store.
• The rapid decay of information in the sensory store distinguishes it from short-term memory (STM).
• If the information were held in STM, participants would likely have been able to remember the presented stimuli for a longer duration.

Highlight: Sperling's study is crucial in establishing the existence and characteristics of sensory memory, which is the first stage in the multi-store model.

Example: If you close your eyes immediately after looking at a bright light, you may still "see" an afterimage for a brief moment. This is an example of sensory memory in action.

This research contributes to our understanding of how information is initially processed before entering short-term memory, supporting the multi-store model's conceptualization of memory as a series of distinct stores.

Page 5: Sperling's Research

This page details Sperling's experimental work on sensory memory.

Example: Participants viewed briefly flashed letters and had to recall them immediately.

Vocabulary: Sensory store refers to the initial memory system where sensory information is briefly held.

Highlight: The rapid decay of information (less than half a second) in Sperling's experiments supports the existence of a separate sensory store.

Page 5: Sperling's Study

Sperling's research provides evidence for the sensory store component of the Atkinson and Shiffrin model of memory.

Example: Participants viewed briefly flashed letters and had to recall them immediately.

Highlight: The study showed that sensory memory decays within half a second, supporting the existence of a separate sensory store.

Page 6: Shallice and Warrington's KF Case

The KF case study challenges the traditional MSM by suggesting multiple STM components.

Highlight: KF's selective STM impairment - poor auditory digit recall but better visual recall - challenges the concept of a unified STM store.

Definition: This case demonstrates that STM might consist of multiple processing systems rather than a single store.

Multi-Store Model of Memory: Glanzer and Cunitz Study (1966)

The Glanzer and Cunitz (1966) study provides significant support for the multi-store model of memory. This research demonstrates the serial position effect, which aligns with the model's assumptions about short-term and long-term memory stores.

Procedure:

• Participants listened to a list of words and were asked to recall them in any order.
• Researchers observed a pattern in recall known as the serial position effect.

Definition: The serial position effect refers to the tendency to remember words at the beginning (primacy effect) and end (recency effect) of a list better than those in the middle.

Evaluation:

• The study supports the multi-store model by showing evidence for separate short-term and long-term memory stores.
• The primacy effect suggests that words at the beginning of the list are rehearsed and transferred to long-term memory.
• The recency effect indicates that words at the end of the list are still in short-term memory.
• Words in the middle of the list are less likely to be remembered due to lack of rehearsal or displacement from short-term memory.

Highlight: This research provides empirical evidence for the distinct nature of short-term and long-term memory stores, a key assumption of the multi-store model.