Memory

short term memory

temporary place for storing information received through the sense

long term memory

permanent place for storing information received through the senses

coding

how sensory input is represented by the memory system

how is info in STM coded?

acoustically (through sound) eg. CAP, CAT, CAN

how is info in LTM coded?

**semantically** (through meaning)

Baddeley (1966)

* Laboratory experiment using 4 independent groups 


* Acoustically dissimilar words were recalled significantly more accurately than similar words (for STM)
* Semantically dissimilar words were recalled significantly more accurately than similar (for LTM)

= s**uggests information is coded semantically in LTM and acoustically in STM**

capacity

how much info can be stored

capacity for STM?

limited to 7 (+/- 2) items

Jacobs (1887)

* Laboratory experiment using digit span technique
* Found that capacity for numbers was 9 items and for letters 7 items

= i**llustrates that capacity of STM is limited**

criticism of Jacobs (1887)

experimental tasks such as recalling lists of letters have little relevance to everyday activities therefore lacking mundane realism

Miller (1956)

* Suggests that capacity of STM is about 7 plus or minus 2 after observations of everyday practice (7 days of the week, 7 deadly sins etc)
* Also noted that people can recall 5 words as well as 5 letters due to chunking

Wagenaar (1986)

* Created a diary of 2 400 events over 6 years and tested himself on recall of events 

= found that he had too excellent recall, **suggesting that capacity of LTM is extremely large**

criticism of Wagenaar (1986)

diary studies are a type of case study and therefore are unrepresentative and there could also be an element of bias as people are testing themselves

duration

how long info can be held in storage

duration of STM

Information **remains within the STM without being lost for 30 secs max**

duration of LTM

Information **can remain in the LTM for the entirety of a person’s lifespan**

Peterson + Peterson (1959)

* Participants were presented with sets of trigrams In a repeated measures design, they were asked to recall the trigrams after a delay of 3, 6, 9, 12, 15, 18 secs -> participants were given an interference task of counting backwards in 3’s from a random number to prevent rehearsal

= 3 secs = 90% recall, 18 secs = 5% recall -> found that duration of STM is approx 18 secs

criticism of Peterson and Peterson (1959)

recalling nonsense trigrams has little relevance to everyday life STM tasks and therefore lacks mundane realism

Bahrick et al (1975)

* Field experiment using opportunity sample of 392 American ex-high school students aged between 17- 74

= Participants who were tested within 15 years of graduation were 90% accurate in photo recognition After 48 years, recall declined to about 70% for photo recognition -> shows that LTM is very long lasting and possibly infinite

The Multi-Store Model of Memory - Atkinson + Shiffrin (1968)

\

sensory store

* an automatic response to the reception of sensory information by the sense organs (5 for each of the senses)

Duration = less than half a sec

Capacity = over 100m cells in one eye storing data

Coding = depends on the sense

maintenance rehearsal

occurs when we repeat material to ourselves

elaborative rehearsal

occurs when we attach meaning (semantic coding) to information in order to transfer from STM to LTM

Glanzer + Cunitz (1966) - Serial Position Effect 

* Primacy effect (LTM) due to enough time to rehearse 
* Recency effect (STM) short amount of time allows it to remain in STM and be recalled

= s**hows there are different memory stores, supporting the MSM,** found that words first and last were most likely to be remembered and recalled 

evaluation of Glanzer and Cunitz (1966)

\+ lab experiment with controlled variables

\- lacks mundane realism as participants are made to memorise meaningless words

Case study of HM 

* removal of his hippocampus left him with anterograde amnesia (unable to make any new conscious memories, ability to transfer information from STM to LTM is affected)
* However, he retained the ability to learn new motor skills

= shows different parts are responsible for memory, supporting MSM

Case study of Clive Wearing 

* Suffered from anterograde and retrograde amnesia (unable to recall memories before the event that caused amnesia, was unable to transfer STMs into LTM)
* However, his procedural LTM was still intact -> was still able to play the piano, without knowledge of being able to

= supporting MSM as STM and LTM stores are seen to be separate

Evaluation of MSM

==-== sees STM as a unitary store which is arguably too simplistic 

\- supported research **lacks ecological validity so it is difficult to generalise** the findings from beyond the experimental setting to memory in real life

\+ supported r**esearch is standardised and controlled, improving the reliability** of the findings

2 systems of LTM

**Explicit** (declarative) -  we have conscious access to 

**Implicit** (non-declarative) - we don’t have conscious access to (like muscle memory)

Types of explicit memory

* semantic
* episodic

semantic memory

* memory of general knowledge, immense collection of material which is constantly being added to 
* **Vicari et al (2007) - Case study of CL**
* **After suffering brain damage, she demonstrated deficiencies in her episodic LTM functions (esp creating new episodic memories) but was still able to create and recall semantic memories**

= **suggests that episodic and semantic memory are separate systems** using different brain areas, with the hippocampus associated with episodic and perirhinal cortex with semantic

episodic memory

* memory of personal experiences and events
* Tulving (1989)
* Using neuroimaging, participants were asked to think about episodic and semantic topics of their choice = found that episodic and semantic LTMs appeared to involve different brain areas and thus are separate forms of LTM

types of implicit memory

* procedural
* emotional

procedural memory

* nonconscious memory for skills, habits and actions
* Finke et al (2012)  - Case study of PM
* The 68 year old professional cellist, suffered brain damage and severe amnesia after contracting an illness
* His episodic and semantic LTM was very affected but his ability to read and play music were not

= suggesting that procedural LTM is separate to the other types

emotional memory

* unconscious memories that evoke an emotional response
* Case study of Clive Wearing 
* Despite suffering from anterograde and retrograde amnesia, he still had emotional strong responses when seeing his wife

= suggests emotional memory is separate

Evaluation of types of LTM (or MSM)

\+ neuroimaging studies show that different types of memory are stored in different parts of the brain

* Tulving (1994) scanned participants’ brains using a PET scanner while they performed various memory tasks (Semantic = left prefrontal cortex Episodic = right prefrontal cortex Procedural = cerebellum) = supports the theory of multiple stores in LTM

\- there are problems with the case studies used to support types of LTM Clive Wearing and HM are very small samples therefore difficult to generalise to help understand LTM in wider, healthy population

\+ identifying different stores in LTM has many real life applications

* Researchers have found that episodic memories can be improved in older people with mild cognitive impairments -> allows specific treatments to be developed which can improve memory and therefore quality of life, With an ageing population, this is important as treatments for illnesses such as Alzheimer's etc

The Working Memory Model - Baddeley + Hitch (1974)

central executive

* **Controls the focus of attention**
* **decides which system (visual or auditory) to use**


* **limited capacity** 
* Controls the 2 'slave controls’ (visuospatial sketchpad and phonological loop)

visuospatial sketchpad

* Deals with the temporary storage of visual and spatial information (AKA the ‘inner eye’)
* limited capacity -> Baddeley suggests around 3-4 objects

phonological loop

* **Deals with auditory information** and preserves word order
* **limited capacity** 
* Baddeley (1978) divided this into 2 subparts:
* Phonological Store = inner ear holds words heard
* Articulatory Process = inner voice keeps information in the PL through subvocal repetition of information (kind of maintenance rehearsal)

episodic buffer

* Temporary store


* Integrates information from the other components and maintains a sense of time, so that events occur in a continuing sequence 
* **Moves information between STM and LTM**
* Limited capacity of about 4 chunks 

Evaluation of Working Memory Model

\+ supporting evidence

* Case study of KF = suggests that just his phonological loop had been damaged leaving other areas of memory intact
* However, evidence from brain damaged patients may not be reliable or generalisable as it concerns unique cases

\- low ecological validity 

* Most research came from lab experiments therefore lacking ecological validity as they may not apply to real life
* However, they can be replicated and are highly controlled making them reliable and accurate

\- studies of VSS and PL often feature a dual task technique

* Tasks performed are often not ones encountered much in everyday life so such studies arguably lack mundane realism

\- Liebermann (1980)

* WMM implies all spatial information is visual, however blind people have good spatial awareness although they have never had visual information
* Therefore, VSS should be separated into 2 different stores, to explain this

types of forgetting

* interference
* proactive interference
* retroactive interference
* retrieval failure
* encoding specificity principle
* context dependant forgetting
* state dependent forgetting

proactive interference

occurs when an older memory interference with a newer one

retroactive interference

happens when a **newer memory interferes with an older** one

* **Baddeley and Hitch (1977) =** found that players who had played the most games forgot proportionately more games than those who had played fewer games
* Support the idea of retroactive interference, with new memories interfering old ones 

Evaluation of interference

\- research into interference tends to use lab experiments based around artificial tasks, therefore lacking mundane realism

\- Use of artificial tasks makes interference much more likely in the lab

\+ thousands of lab experiments have been carried out into this explanation for forgetting, these contribute to the validity and accuracy as they are controlled

\+ research like Baddeley and Hitch (1997) have high ecological validity due to their research in real life scenarios

encoding specificity principle

retrieval of memory is optimal when the retrieval condition (context/cues) duplicate the conditions that were present when the memory was formed (Tulving, 1983)

context dependent forgetting

occurs with external retrieval cues, with forgetting occurring **when the environment is different** at recall from how it was at coding

state dependent forgetting

occurs with internal retrieval cues, with forgetting occurring **when the individual’s internal environment is dissimilar** at recall to when information was coded

* **Carter and Cassaday (1998)**
* Gave antihistamines (which cause drowsiness) or a placebo to participants and Asked to learn and recall in 4 different conditions of learning and recalling 
* Showed a marked decrease in accuracy of recall in a memory test when the participants' internal state did not match at the time of encoding and retrieval and and increased performance when the states did match
* = supports concept of state dependent forgetting 

Evaluation of retrieval failure

\+ a range of research supports this explanation (Seddon (2019), Godden and Baddeley (1975), Carter and Cassaday (1998) etc)

\- context dependent forgetting effects are arguably not strong in real life 

* Baddeley (1997) argues that contexts have to be very different before an effect can be seen, so real life applications of RF don’t actually explain forgetting 

\+ real life application

* Basic principle of the cognitive interview!

factors affecting eyewitness testimony

* Reconstructive memory
* Leading questions, weapon focus, anxiety levels, conformity etc.
* 72% of convictions overturned by DNA testing involved EWT that was not accurate (source: The Innocence Project)

Loftus and Palmer (1974)

* 45 students were shown 7 different films depicting traffic accidents
* Following each film, participants are given a questionnaire, with a question asking ‘How fast were the cars going when they hit each other?’ with the word ‘hit’ being replaced by ‘smashed’, ‘collided’, ‘bumped’ and ‘contacted’ -> Participant answered with faster speeds with the words ‘smashed’ or ‘collided’ than the words ‘hit’ or ‘contacted’

**= Found that the form of a question can markedly and systematically affect a witness’ answer**

Evaluation of Loftus and Palmer (1974)

\+ application in real life

* Used in formulating guidelines for police questioning of witnesses

\- small sample size of 45

\- only students are used in this experiment, due to their relatively young age they are likely to remember better so ungeneralisable

\+ has high mundane realism

\+ lab experiment so confounding variables were controlled, therefore ensuring they did not affect results

\- lacks ecological validity as they are just watching a video

substitution explanation

the wording of a leading question changes the memory of the participant

post event discussion

when co-witnesses to a crime discuss it with each other, their EWTs may become contaminated

\-> this is because they combine (mis)information from other witnesses with their own memories

memory conformity

when a witness goes along with a co-witness’ version of events

reconstructive memory

suggests that in the absence of all information, we fill in the gap to make sense of what happened

* **Fredrick Bartlett (1932) - The War of the Ghosts**


* **Allport and Postman (1947) - The Psychology of Rumour**
* **Showed an image of a white man threatening a Black man to participants** 
* **Participants then had to retell the description to others and this was repeated in a sequence**

= **found that the description of the photo was simplified and distorted to the Black man threatening the white man, showing the effect of schemas on memory as well as reconstructive memory** 

processes of reconstructive memory

* **Levelling** - condensing/cutting information
* **Sharpening** - focusing only on specific things you remember
* **Assimilation** - fitting memory to our schema

response bias explanation

suggests that the wording of the question has no real effect on the participants memories, but just influences how they decide to answer

Gabbert et al (2003)

* Pairs shown video of the same crime but from a different viewpoint, they then had to discuss what they had just seen


* **71% of pps falsely recalled events they had not personally seen but picked up from the post event discussion**

= witnesses often go along with each other either to win social approval or because they believe the cowitness has correct information (memory conformity)

effect of anxiety on EWT

If anxiety is too high or too low when witnessing an incident, the EWT and memory is much less reliable. With just enough anxiety, memory is optimal and is at its best in EWT

Johnson and Scott (1976)

* Invited participants to a lab where they were told to wait in the reception area alone
* Both groups were then shown 50 photos and asked to identify the person who had left the lab -> those who had witnessed the man holding the pen were correct 49% of the time, whilst those who witnessed the knife were correct 33%

= Loftus claimed that pps who were exposed to the knife had higher levels of anxiety and more likely to focus their attention on the weapon (weapon focus effect) -> therefore, the anxiety associated with seeing a knife reduces the accuracy of EWT

Biological evidence for the Yerkes-Dodson law

* Research found that excessive or too low levels of cortisol (stress hormone) means long term potentiation is harmed. 
* With just enough cortisol, long term potentiation reaches an optimal point, proving the Yerkes-Dodson law

**Fisher and Geisalman (1984**) - The Cognitive Interview

an interview method designed to reduce leading questions and enhance a witness’ memory of events

Designed to:

* Facilitate maximum recall 
* Prevent confabulations (false/distorted memory)

Processes of the Cognitive Interview

1. **Report everything** 

Witnesses should be asked to report everything, however trivial. This may trigger other, important memories.


2. **Context reinstatement** 

Restate the exact context of the event 


1. External 
2. Emotional
3. Cognitive 

Memory is enhanced when the psychological environment at the interview is similar to the environment at the original event  (Links to the encoding specificity principle)


3. **Reverse the order**

Recall in a different order to prevent people reporting their expectations of how things normally happen

May prevent witness unconsciously relying on schema and reconstructive memory  


4. **Change perspective**

Recall form a different viewpoint to disrupt the effect of schema on recall

**Fisher et al (1989)**

Field experiment 

Using the cognitive interview technique, r**esults showed a 47% improvement in the accuracy of recall compared to when they had been using standard interview** technique