AO1, Description – Definition of Memory:
Memory: The process by which we retain information about events that have happened in the past. This includes fleeting (short term) memories as well as memories that last for longer (long term). Research has identified a number of key differences between short-term memory (STM) and long-term memory (LTM) in terms of the way these types of memory work.
A model of memory is a theory of how the memory system operates, the various parts that make up the memory system and how the parts work together.
AO1, Description – The Multi-Store Model (MSM) of Memory: Atkinson and Shiffrin
The most well-known and influential model of memory was put forward by Atkinson and Shiffrin in 1968. They proposed that human memory involved:
- A flow of information through an information processing system.
- A system divided into 3 stages or storage components i.e., Sensory Register (SR), Short-term Memory (STM) and Long-term Memory ( LTM).
- Information passing from one stage to another in a fixed sequence.
- Constraints (or restrictions) at each stage in terms of capacity (size, i.e., how much each stage can hold), duration (length of time the memory stays in each stage) and coding (the way the information is stored at each stage e.g., visual images or sounds).
There are three limitations (or constraints) to the separate memory stores which are:
(1) Coding: The way that information is represented in the memory store (e.g., by sound [auditory], meaning [semantic] or image [visual]).
(2) Duration: The length of time that memories can be held within the memory store.
(3) Capacity: The amount of information that can be held in the memory store at any one time.
|Sensory register||Short-term memory||Long-term memory|
|Key research||Key research||Key research|
|Coding||Deals with information from the 5 senses:
Haptic, Echoic, Iconic, Olfactory,
|Crowder (1993) found that the SR had different durations for each information type – indicating different processing all types||Acoustic||Baddeley gave participants 2 lists of words to remember for immediate recall.
List 1 = acoustically similar, List 2 = acoustically dissimilar.
Increased errors were made in List 1
|Semantic||Baddeley gave participants 2 lists of words to remember for immediate recall.
List 1 = semantically similar, List 2 = semantically dissimilar.
Increased errors were made in List 1
Flashed a 3×4 grid of letters for 1/20th /s and asked for recall of one row. Recall was high, which suggests all the information was originally there.
|5-9 items||Jacobs (1887) gave participants increasingly long number lists for immediate recall. Jacobs found that the capacity ranged between 5-9||Unlimited||Anokhin (1973) estimated the number of neuronal connections in the human brain as 1 followed by 10.5 kilometres of noughts.|
|Triesman (1964) played identical auditory messages to both ears, with a slight delay between presentations. Ps noticed they were identical if the delay was 2s or less.||Seconds||Peterson & Peterson (1959) read nonsense trigrams to participants (e.g. ZFB) & asked them to count backwards in 3s from a large 3-digit number (to prevent rehearsal). After a specific length of time the participants were required to recall the trigram; 90% recall after 3s, 5% recall after 18s||Lifetime||Bahrick et al (1975) showed participants aged between 17-47 a set of photos and a list of names, some of which were ex-school friends. Those who had left school within 15 years had 90% recall for faces & names, those who left within 48 years had 80% recall for faces & 70% recall for names.|
The Multi-Store model of memory (MSM), AO1, Description:
According to Atkinson and Shiffrin:
- The sensory store is constantly receiving information from the environment. Most of this information receives no attention and so is lost through However, if the information that enters the sensory stores is attended to (paid attention) then this information is encoded and passes through to the short term memory (STM).
- Once in the STM, information (if not rehearsed), can be lost through either displacement (this is because the STM has a capacity of 7+/- 2 items) or decay (as the STM only has a duration of 0-18 seconds).
- If information is elaborative rehearsed (over and over…) and the information is understood, then the information will be transferred /encoded into the long term memory (LTM).
- The LTM can hold information for an unlimited about of time and has an unlimited capacity.
- When stored information is needed, it can be retrieved from the LTM back to the STM.
- Atkinson and Shiffrin proposed a direct link between rehearsal in the STM and the strength of the long term memory.
Evaluation, AO3 of The Multi-Store Memory Model
(1) Point: Further research from brain scanning techniques has supported the Multi-Store Memory model and the idea of separate memory stores (i.e. a short term memory store and a long term memory store. Evidence: Squire et al (1992) used brain-scanning techniques and found that STM can be associated with activity in the prefrontal cortex and that LTM can be associated with activity in the hippocampus. Evaluation: This is a strength because it provides biological evidence that the different types of memory are processed by different parts of the brain and that the memory stores are distinct as the multi-store model suggests.
(2) Point: Case studies of brain damaged patients (e.g. KF) have also offered support for the Multi-Store Model of memory. Evidence: Shallice and Warrington (1970), reported the case of KF, who was brain damaged as a result of a motorcycle accident. His STM was severely impaired, however his LTM remained intact. Evaluation: This supports the view that STM and LTM are separate and distinct stores and therefore supports the proposals of the Multi-Store Model of memory as it shows that it is possible to damage only one store in memory.
(3) Point: The main strength of the MSM come from support for the idea that at least two separate memory stores do exist (i.e. STM and LTM). Evidence: Murdock’s (1962) Serial position effect (laboratory experiment): – Murdock argued that no matter how many words a person is shown and then asked to recall, items at the beginning of the list are recalled to a greater degree than those in the middle, while words at the end have a greater recall than either the beginning or the middle. Words recalled at the beginnig are rfered to as the primacy effect, words remembered at the end of the list are refered to as the recency effect. Evaluation: This supports the MSM because the fact that participants remember words more at the beginning of the list is due to the fact that these words are rehearsed and are starting to pass into the LTM (as suggested by the MSM). Words in the middle of the list are not remembered as well due to the fact that these words are not rehearsed and therefore are lot through displacement. Finally, as suggested by the MSM, the words at the end are remembered well due to the fact that we can hold words in in our STM without rehearsal for up to 30 seconds.
(3) Point: Case studies of brain damaged patients criticise the MSM. Evidence: The case of KF demonstrated that his deficit in STM was for verbal information and that the STM for visual material was normal. Evaluation: This is a weakness because it demonstrated that it is possible to damage only part of the STM going against the MSM idea that STM is unitary (suggesting that there may be more than one type of STM).