Models of memory

MSM

• The multi-store model of memory (MSM) was devised by Atkinson & Shiffrin (1968) as a way of conceptualising the processes by which memories are encoded and stored

• The model is a linear representation of the ways in which information is either retained and stored in the memory or lost, e.g. due to lack of rehearsal

MSM Process

• Incoming info is automatically stored briefly in the sensory register – where senses may initially interpret information at an unconscious level

• Paying attention to this information transfers it to short-term memory (STM) and then we become conscious of the info. Only around 1% of all info in our sensory memory reaches the STM.

• If info in STM is rehearsed (repeated consciously or unconsciously) Rehearsal keeps info in the STM. It is also responsible for transferring info to the long-term memory (LTM). This allows us to encode info

• If info is not rehersed it is lost from STM according to the FIFO principle (First in first out – info that entered the STM first is lost first). Older info or info is displaced and quickly decays. Duration = 5-15 seconds, can store between 5-9 items

• Over time some info can be lost from LTM. Or forgetting can occur if memories are stored but the retrieval process does not work. We may recall the wrong information (interference). Capacity: unlimited, duration: infinite

Sensory Memory (MSM)

• Encoding: 5 sense

• Capacity: everything

• Duration: 250 milliseconds

• Forget: Not paying attention

Short term memory (STM) (MSM)

• Encoding: Acoustically

• Capacity: 5-9 items

• Duration: 5-15 seconds

• Forget: displacement (FIFO)

Long term memory (MSM)

• Encoding: Semantically

• Capacity: Unlimited

• Duration: Infinite

• Forget: Interference

Study: Case study - Henry Moliason (HM)

• Longnitudinal Case study – data collected over years.

• HM (Henry Moliason) – bike accident which resulted in epilepsy. Had part of his temporal lobe removed – specifically the hippocampus.

• Method triangulation: tests, experiments, interviews, observations, medical records

• Data triangulation: results of the experiments/tests

• No damage to personality, to prior memories. Unable to learn new memories. Unable to learn new memories (declarative) but could acquire new skills (procedural memories)

• Proves MSM structure that it is a linear structure because without Henry’s short term memory he can’t create long term ones

Strengths of HM

• longitudinal - over 50 years!  This means that change could be observed over time.  In addition, case studies use method triangulation.

• 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.

Limits of HM

• 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 study was retrospective. we do not have a lot of data on HM's actual cognitive abilities before the accident.

• medication taken to treat epilepsy may have resulted in some of the damage, but this is not highly relevant as it is the damage to specific parts of the brain that is important

Strengths of MSM

• There is significant research to support the theory of separate memory stores - both in experimental research and biological case studies of patients with brain damage.

• The model is of historical importance. It gave psychologists a way to talk about memory and much of the research which followed was based on this model.

Limitations of MSM

• The model is over-simplified. It assumes that each of the stores works as an independent unit.

• The model does not explain memory distortion.

• The model does not explain why some things may be learned with a minimal amount of rehearsal. For example, once bitten by a dog, that memory is quite vivid in spite of the lack of rehearsal.

• There are several times that we rehearse a lot to remember information and it is not transferred to LTM.

Schema theory

• Schema are mental representations that are derived from prior experience and knowledge.

• bottom-up information derived from the senses is interpreted by the top-down influence of relevant schemas in order to determine which behavior is most appropriate.

• Schemas help us to predict what to expect based on what has happened before

Bartlett War of Ghosts - Aim

investigate how the memory of a story is affected by previous knowledge

Bartlett War of Ghosts - Procedure

• Told participants a Native American legend called the The War of the Ghosts. Participants were British, story was filled with unknown names and concepts, and the manner in which the story developed was foreign.

• Allocated participants to one of two conditions: group 1, asked to use repeated reproduction (heard the story then told to reproduce it after a short time and then to do so again repeatedly over a period of days, weeks, months, or years). Group 2, asked to used serial reproduction (recall the story and repeat it to another person)

Bartlett War of Ghosts - Results

• No significant difference between the way that the groups recalled the story. Found that both conditions changed the story as they tried remember it (distortion – act of giving misleading account or information). Found 3 patterns of distortion:

• Assimilation: the story became more consistent with the participants own cultural expectations – details change to fit British cultural norms

• Leveling: the story became shorter with each retelling as participants omitted information that was “not important”

• Sharpening: participants tended to change the order of the story in order to make sense of it, using terms more familiar to the culture of participants. Also added detail/or emotions

• Overall remembered main themes, but changed unfamiliar elements to match cultural expectations, so the story remained a coherent whole

Bartlett War of Ghosts - Findings/link

Study indicates that remembering is not a passive but rather an active process, where information is retrieved and changed to fit existing schemas. Done in order to create meaning in the incoming information.

Bartlett strengths:

• Bartlett's theory of reconstructive memory has several applications and explains many real-life situations. Thus, despite being carried out in a laboratory, it has high ecological validity.

Bartlett limitations

• Many textbooks conclude that culture affects our ability to recall information correctly; however, that is not the finding of this study.  The participants were British because it was assumed that the story would be culturally unfamiliar to them; in other words, they would not have the schema that would help to recall the study

• If we wanted to study the effect of culture on our ability to recall this story, we would have to carry out a quasi-experiment; there would have to be the British group and the Native American group, and the number of details correctly recalled would have to be compared.

Schema theory strengths:

• application; Early Maladaptive Schemas - pervasive, self-defeating patterns of thought, emotion, and behavior that develop during childhood and continue to influence individuals throughout their lives (example Riso et al, found EMS are stable over time for those with depression)

• Unbiased: Schema theory is applied across cultures. There is no apparent bias in the research, although most of the early research was done in the West.

• Predictive validity: The theory helps to predict behavior. We can predict, for example, what types of information will be best recalled when given a list of words. Trends, such as omitting information that is not of high relevance to the individual, are commonly seen in individuals recalling a news story. However, we cannot predict exactly what an individual will recall.

Limitations of schema

• concept of a schema is often too ambiguous and lacks precise definitions, making it difficult to understand and apply in research contexts.

• does not clearly specify the processes involved in schema formation, activation, and modification. This lack of detail makes it challenging to understand how schemas are created and how they influence cognitive functions like memory

• Many studies supporting schema theory are conducted in controlled laboratory settings, which may not accurately reflect real-world situations. This raises questions about the ecological validity of the findings and their applicability to everyday cognitive processes

Key differences between Schema and MSM

• Schema Theory explains distortion/confabulation – MSM does not​

• Schema Theory does not explain where memory is stored ​

• Schema is more holistic because it can be applied culturally, while MSM is reductionist because it is linear

• MSM has a structure, schema is ambiguous