1. Memory Models

Key concepts

Cognition

The mental process of acquiring knowledge and understanding through thought, experience, and the senses. One of the cognitive processes is memory.

Memory

The process which the information is encoded, stored, and retrieved

1. Encode – the input of information into the memory system
2. Stored – is the retention of stored information
3. Retrieved – getting information out of memory storage

Multi-store model

• Proposed by Atkinson and Shiffrin
• It argues that memory could be consisted of various stores.

	Capacity	Duration	Condition for entering
Sensory memory	Unlimited	Smaller than a second
Short-term memory	Limited	Smaller than a minute	Attention
Long-term memory	Unlimited	Permanent	Rehearsed

Evaluation of MSM

Strength

Model pioneered the new approach to memory where humans are seen as information processors.

The fact that we have multiple stores is supported by research. Has empirical evidence. 

Limitation

Does not explain memory distortion.

Single-store version has been challenged, since LTM contains several stores.

 

Working memory model

• Proposed by Baddeley and Hitch
• Suggests that STM have different stores: Phonological loop, visuo-spatial sketchpad, the episodic buffer.

Central executive	The central commander of the system that coordinates and monitors the operation of other subordinates relates them to LTM
Phonological loop	The system that deals with written and spoken information Articulatory process: process speech production and rehearse information.
Visuo-spatial sketchpad	Stores and processes visual information about form and color, as well as deals with spatial and movement information.
Episodic buffer	Integrating the information in the other two component of WMM. It is a limited amount of storage that transfer the two components into LTM.

 

Contrast two models

Difference

• The two models differ majorly in the way they describe short-term memory.
• The Multi-store model illustrates STM as a single store but the Working Memory Model on the contrary explains short-term memory as having four components to it and different modalities are processed differently-that is, visual/spatial vs. auditory information.
• The working memory model focuses on STM and explains short-term memory in some detail while multi-Store model has just laid out general steps of memory that SM through selective attention transfer to STM and LTM Encoded from STM Store through rehearsal.
• The WMM explains how we can multitask in some cases.
• The MSM describes the loss of memory through decay.

Similarity

• Both models have made helpful contributions to psychology, but the Working Memory Model is an improvement upon the original MSM, and they are different in fundamental structure. The Working Memory Model challenged the MSM by saying that short-term memory is more complex than just one single store. Latter studies that used this model found it to be true.

 

Studies

Milner and Scoville (1957)

Aim

To assess the effects of having one’s cognitive ability when hippocampus is removed.

Design

• Case study with triangulation.
• Observations at home, Interviews – with Henry and his parents, IQ tests, Memory tests, such as the star-tracing task and asking Henry to remember numbers.

Result & Conclusion

HM’s long-term memory was mostly fine, but the transfer from STS to LTS was damaged.

Link-back

• This suggests memory transfers from one store to another because if all memories were in one store, people like HM wouldn’t have been able to keep information in his short-term store but not transfer it to the long-term store (it would be all or nothing if they were the same store)
• The star-tracing task also shows that the function of the hippocampus might be specifically related to declarative (explicit) memory and not to procedural (implicit) memory.

Evaluation

Method triangulation, various methods are used in the study of HM; hence, providing it a high reliability. To be specific, methods like interview, observation, activity testing, survey are all used in the study. This has, hence, offered the researcher a more holistic and in-depth view of how the loss of one brain part will lead to damage of others.

One limitation is that the study apparently only used one sample to study, the generalizability of the result could be called in to question. The special injury caused by car accident and the treatment for removing hippocampus received by HM is unique, other people will not have the similar experience to that. 

 

Glanzer and Cunitz (1966)

Aim

To investigate the serial position effect with and without interference from a filler activity. 

Design

• Lab experiment (Repeated measure design)
• 46 army-enlisted men divided into three conditions.
  • Condition 1: free-recall task
  • Condition 2: count out backwards from a random number (filler activity) for 10 seconds
  • Condition 3: do filler activity for 30 seconds. 

Result & Conclusion

• Condition 1: the primacy and recency effect can all be observed.
• Condition 2&3: the primacy effect stayed, but the recency effect disappeared. The same result generated more significant in the group that counting backward for 30 seconds.

Link-back

• The first words on the list get rehearsed more often and enter the long-term memory, due to the primacy effect. This is unaffected by the delay and the filler task.
• However, the recency effect disappears after the filler task in condition 2&3.
• Since one of the effects disappears and the other does not, so STM and LTM have separate memory mechanisms.

Evaluation

The advantage of this study is low participant variability, because the experiment design used was repeated measure. The accuracy and capacity of memory are different among people, therefore making this variable especially important to control in memory test. 

However, repeated measure design also brings one limitation to this study, which is order effect, and more specifically, the fatigue effect. Participant must do the memory task for several times, because repeated measure requires them to go through all conditions. The tiredness of participant may start to affect their memorizing ability negatively.

 

Landry and Bartling (2011)

Aim

To investigate if articulatory suppression would influence recall of a written list of phonologically dissimilar letters in serial recall. 

Articular suppression is a research technique where participants are required to repeat a sequence of sounds while at the same time performing the experimental tasks. 

Design

• Lab experiment (Independent sample design)
• 34 Psychology students divided into two groups.
  • Experimental group: articulatory suppression task, say 1 and 2 per second while see list of words. 
  • Control group: 5 seconds to see the list, wait for another 5 seconds then recall words in order without any other instructions. 

Result & Conclusion 

Experimental group recall words lower than control group

Link-back

• With the Working Memory Model, articulatory suppression prevents rehearsal in the phonological loop because of overload. 
• This resulted in difficulty in memorizing the letter strings for participants in the experimental conditions whereas the participants in the control condition did not experience such overload.

Evaluation

The study has relatively high control on confounding variables. For example, the list of letters is doesn’t sound similar, and there is no vowel, so there is fewer factors to assist the participant’s memorizing process. This makes sure that the effect of articulatory suppression can be fully presented and infer causation.

However, this study has sampling bias. All participants are psychology students who involve frequent memory task in their studying. So, it’s very likely that the participant in this sample have higher memorizing ability than average level. Normal people may have an accurate rate that are lower than 75% in the first condition. So, this result cannot be generalized.