Models of Memory
The Multi-Store Model of Memory and The Working Memory Model provide a framework for an understanding of conceptualization of human memory processes over time. The multiple-store model demonstrates the process of memory formation. The working memory model is an elaboration of short-term memory, suggesting a number of components working together to process information.
Serial Position Effect
Primacy Effect:
The first few items are recalled more frequently than the middle items (lingers longer in long-term).
Recency effect:
Recall items that are close in time periods (recalled better in short-term).
Murdok (1962)
defined the serial position effect in the linear presentation of information.
The aim of the study was to see if the length of a list of words and the pace at which the words were read would have an effect on the serial position curve.
The sample consisted of 103 introductory psychology students. The study used an independent sample design.
Participants were randomly allocated to one of six conditions. In three of the conditions, the words were read at a pace of one word per second. In the other three conditions, the words were read at a pace of one word every two seconds.
Each group read 80 lists of commonly used English words and recalled the words after each list was read. For each participant, the mean number of words recalled was calculated.
Although the practice effect did lead to a significant difference in performance over time, the biggest improvement was 1.13 words. The pace of the presentation did not make a difference. There was no significant difference found.
The study produced six different serial position curves. In all cases, the greatest number of words was recalled at the end of the list due to the recency effect. This was followed by the words at the beginning of the list. The asymptote was most obvious in the list of 40 words. In the 10-word list, the primacy and recency curves intersected and there was no asymptote. This is most likely due to the fact that we can hold 7 +/- 2 pieces of information in STM.
The study is beneficial as it provided evidence that there are different stores for the different types of memory, which is what Atkinson and Shiffrin proposed in their multi-store memory model (1968).
Another strength of the study is that other studies such as Glanzer and Cunitz (1966) found supporting evidence. Coherent results also further support that the recency effect results from the STM temporarily storing the words.
The study recruited a non-representative sample. The study recruited psychology students, so they may have been able to guess the study's aims and act accordingly to the Hawthorne effect. Moreover, as the study used a small sample, it isn't easy to generalise the findings to the population.
The study can be reductionist, as it over-simplifies
by measuring the ability based on the accuracy of recalling a list of words. Different results may be found if we measure different types of memories, names or words with associations.
Multi-Store Model
Sensory Memory (感官所接受的信息)
Short-term Memory (易忘的, information usually stay for 6-12 seconds.)
Miller argued than memory capacity is 7+-2 pieces of information.
Rehearsal (不断练习巩固), helps memory to move from STM to LTM
Long-term Memory (长期记忆, 无法忘掉)
Milner (1966) Biological Support
It is a longitudinal case study which investigated the role of the hippocampus on memory formation.
HM had undergone for epilepsy that resulted in the removal of most of his hippocampus and parts of his amygdalae.
Researchers applied method triangulation like psychometric testing, direct observation of his behaviour, and interviews with both HM and with family members.
They found out that HM could not acquire new episodic knowledge (memory for events) and he could not acquire new semantic knowledge (general knowledge about the world). This suggests that the brain structures that were removed from his brain are important for the transfer of information from short-term to long-term memory.
The researchers also found that he was able to remember his house and could draw a picture of the floor plan of his new home. This indicates that he was able to form a cognitive map of the spatial layout of his house. This may mean that this type of memory is not encoded in the same way as semantic or episodic memories.
HM had a capacity for working memory, since he was able to carry on a normal conversation. This requires a minimal level of retention of what has just been heard and said. On being asked to recall the number 584, HM was able to do so even 15 minutes later, apparently by means of constant rehearsal. However, after the task was over, HM would not be able to recall the number.
The study was a case study. The strength of this study is that it was longitudinal - over 50 years! This means that change could be observed over time. In addition, case studies use method triangulation.
The limitation of case studies is that they cannot be easily replicated. However, there are several other case studies of patients like HM - for example, Clive Wearing - which confirm the findings.
Some of the study was retrospective in nature. This means that we do not have a lot of data on HM's actual cognitive abilities before the accident.
High ecological validity , no variables were manipulated and HM was observed in his natural environment.
Milner's research met high ethical standards of consent, confidentiality and protection from harm.
The study supported that the memory systems in the brain constitute a highly specialized and complex system. The hippocampus specifically plays a critical role in converting memories of experiences from short-term memory to long-term memory.
Does not explain memory distortion
The model does not explain why some things may be learned with a minimal amount of rehearsal.
The levels of processing Theory challenges this model, showing that process of information may be more important than the frequency of rehearsal.
There are several times that we rehearse information and it is not transferred to LTM.
Working Memory Model
Central Executive
role: directs attention to tasks.
Automatic level: automatically processing (daily tasks)
Supervisory attention: planning and decision-making.
Phonological Loop
Role: Auditory information and language - both written and spoken
Baddeley subdivided it into the phonological store (holds word heard) and the articulatory process (holds words heard/seen)
Visuospatial Sketchpad
Visual and spatial information
Visual cache = what things look like, stores information about form and color
Episodic Buffer
role: linking information to form integrated units
Holds several sources of information
Display store until the information is needed.
Landry and Bartling (2011)
to see if articulatory suppression would influence recall of a written list of phonologically dissimilar letters in serial recall.
The researchers used an independent samples design with a sample of thirty-four undergraduate psychology students.
There were ten lists each consisting of a series of 7 letters.
In the experimental group, participants received instructions to repeatedly say the numbers '1' and '2' from the time of presentation of the list until the time they filled the answer sheet. Each trial was scored for the accuracy of recall.
The control group saw the letters but did not carry the articulatory suppressions task.
The results showed that the mean percent if accurate recall for both groups was 76% compared to a mean of 45% in the experimental group.
The strength of this study is that it can be easily replicated since it is a true experiment everything could be manipulated under lab conditions that are highly controlled. It has a high internal validity, which cause and effect relationship can be determined.
The limitation of case studies is that the results are artificial and highly controlled not reflective of real work thus lacks ecological validity
The sample size of the study is too small, which reduces the generalisability of results.
In line with the WMM, articulatory suppression is preventing rehearsal in the Phonological Loop because of overload. The data supports the prediction of the WMM that disruption of the Phonological Loop results in less accurate working memory as it has a limited capacity.
Help us to understand why we are able to multi-task in some situations and not in others
How the various components of the model interact is not clear
Central executive is unclear
Didn’t explain the process of central executive going to phonological loop, visuospatial sketchpad, episodic buffer.
Did not explain memory distortion.
Schema Theory
Cognitive schemas are seen as mental representations that organize our knowledge, beliefs and expectations. Multiple studies have indicated that schemas influence memory processes in encoding, storage and retrieval. Schema processing is to a large extent automatic and non-conscious which saves cognitive energy but at the same time could result in biases in thinking and memory processes.
Relevant Concepts
top down, bottom up processing
pattern recognition -- the matching of a current input to information in memory
effort after meaning -- the attempt to match unfamiliar ideas into a familiar framework
stereotyping -- an example of schema processing based on a fixed mental representation on a group of people
Reconstructive Memory
Human memory is not an exact copy of events but rather a reconstruction that may be altered over time, through discussions with others or input from the media. Research shows that memory may be changed during storage, processing and retrieval, for example, due to schema processing. Knowing this could be important not only in Human memory is not an exact copy of events but rather a reconstruction that may be altered over time, through discussions with others or input from the media. Research shows that memory may be changed during storage, processing and retrieval, for example, due to schema processing. Knowing this could be important not only in
Relevant Concepts
top down, bottom up processing
pattern recognition -- the matching of a current input to information in memory
effort after meaning -- the attempt to match unfamiliar ideas into a familiar framework
stereotyping -- an example of schema processing based on a fixed mental representation on a group of people
