Saturday 29 June 2019


~ Improving accuracy of eyewitness testimony ~


~ Factors affecting eyewitness testimony ~


~ State-dependent forgetting ~


~ Retrival failure ~

Encoding specificity principle – Tulving research into rereival failure. Summerised this pattern encoding specificity principle if a cue is to help us to recall information it has to be present at encoding where the material was learned and at retrieval. 
If cues available at encoding and retrieval are different. 
Cues are linked to the material-to-be remembered in a meaningful way. Such cues are used in many mnemonic techniques 
Context-dependent forgetting 
State-dependent forgetting. 

Context-dependent forgetting 
Godden and Baddeley 1975 – deep sea divers working underwater. 
Critical for divers to remember instruction given before their work (matter of life or death) 
Learn on land – recall on land 
Learn on land – recall underwater 
Learn underwater – recall on land 
Learn underwater – recall underwater 
Recall 40% lower in non-matching conditions external cues available at learning were different from ones at recall and this led to retrieval failure.


~ Explanations for forgetting ~

Retroactive interference 
Old information/memory is disrupted by the new learned information 

Proactive interference 
New information/memory is disrupted by the old learned information.

McGeoch and McDonald 1931 
Study of retroactive interference by changing the amount of similarity between two sets of materials. PPT has to learn a list of 10 words until they could remember them accurately then learned new set of words 
6 groups =
1)    Synonyms 
2)    Antonyms 
3)    Words unrelated to original ones 
4)    Nonsense syllables 
5)    3 digit numbers 
6)    No new list 
Similar material had the worst recall // interference is strongest when memories are similar. 

ü Real life studies = Baddeley and Hitch 1977 wanted to find out if interference was a better explanation for forgetting than passage of time.  The accuracy of the recall is based on the number of games played rather than depending on how long ago the matches took place. 
ü Interference can be overcome using cues – Tulving and Psotka 1971 gave participants five lists of 24 words organised into 6 categories – hut, cottage, hill, etc. categories not explicit recall 70% for the first word list but fell when additional lists were given to learn. Then given cued recall test – recall rose again to about 70%.  

×     Artificial material – interference would be greater in lab studies rather than in real-life situations. The stimulus materials used in most studies are lists of words. Interference may not be as likely an explanation for forgetting in everyday life as it is the lab.


~ Working memory model ~

For short term memory. 

Central executive: attentional process that monitors incoming data/information and allocates it into the slave systems. – limiting processing capacity.

Phonological loop: one of the slave systems. Preserves the information in the order of which arrives in. 
Sub-divided stores 
1.    Phonological store – stores the words you hear. 
2.    Articulatory process – allows maintenance rehearsal (repeating words in a loop) 

Visuo-spatial sketchpad: second slave system. Stores visual and spatial information. Has limited capacity according to Baddeley 2003 – 3-4 objects 
Logie 1995 – subdivided VSS:
Visual cache – stores visual data 
Inner scribe – records the arrangement of objects in visual field. 

Episodic buffer: third slave system. Added by Baddeley 2000. Temporary store for information, intergrating the visual, spatial and verbal information processed by other stores and maintaining a sentence of time sequencing – can be seen as a component of central executive // has a limiting capacity of 4 chunks Baddeley 2012 // linked working memory to LTM wider cognitive processes – perception. 

ü Studies of dual-task performance supports the separation existing visuo-spatial sketchpad. Baddeley et al 1975 more difficulty doing two visual tasks at the same compared to doing one visual and verbal task. 
×     Lack of clarity over the central executive – is unsatisfactory and doesn’t really explain anything. // needs to be more clear than it simply pays attention – some argued that the WMM hasn’t been fully explained. 

ü Brain scanning studies support the WMM // Braver et al 1997 gave their participant tasks that involved the central executive during brain scan. Researchers found greater activity in an area greater activity left prefrontal cortex the activity of the area increased as the tasks got harder. Demands of the CE increase has to work harder to fulfil its function.


~ Types of long term memory ~

Implicit// involves unconscious thought 
  • Procedural:  Allows us to perform learned tasks with little/no conscious thought such as walking and riding a bike

Explicit// involves conscious thought 
  • Semantic: General facts and knowledge, not time stamped, less personal. 
  • Episodic: Memories of events which have taken place in our lives, consist of personal facts and experiences.

Areas of the Brain:
  1.  Episodic Memory- Prefrontal cortex, also associated with memory storage, neocortex, all connected to the hippocampus.
  2. Semantic Memory- Hippocampus and coding is 1.    mainly associated with the frontal, temporal lobes.
  3. Procedural Memory- Neocortex areas in the brain, primary motor cortex, cerebellum and prefrontal cortex.


*     Episodic Memory- Herlitz (1997) 100 Swedish participants, explicit long term abilities tested, researching gender differences in episodic memory, females performed better than males.
*     Semantic Memory- Kroeing (2007) created 64 imaginary but believable drawing of dogs, one was prototype for cutters (Animals shared 3 similar features). Alzheimer and  Non-Alzheimer took part, deciding which out of 64 pictures were cutters, Alzheimer participants were as good as Non-Alzheimer participants when directly comparing, but inferior when using stated rule as it requires higher level of processing, suggesting semantic memory involves different processes and brain areas. 
*     Procedural Memory- Finke et al (2012) a 68 year-old professional cellist with encephalitis, resulted in amnesia, his episodic and semantic LTM were very affected, he could not remember musical facts such as names of composers, but his ability to read and play music was unaffected.


Procedural Memory- 
×     Problem in deciding which brain areas are involved in procedural memory is the lack of research, cases of people with brain damage which affects procedural memory is needed but not explicit memory this is rare.
Procedural memories take longer to learn than explicit, this may be because procedural memory requires motor functions and spatial abilities explicit tends not to. 


~ Multi-store model ~

Proposed by Atkinson and Schifrin – information is passed between the stores in a linear way.
Sensory register > Short term memory > Long term memory 

Sensory register receives information from a stimulus. This information would come from environment. 
Two main stores = iconic memory – visual information is coded – echoic memory – sound information 

If the information is paid attention to then it gets passed onto the short-term memory. If any information is not important then the information is decays or disappears. Or if there is not enough rehearsal then the information is displaced or decays. Maintained rehearsal – when repeating material to ourselves over and over again. Long enough to pass into the long-term memory. 

Once in the short-term memory informed can be rehearsed and some information is rehearsed and the passed into the long term memory.
Memory is stored in the long-term memory however to retrieve it when recalling information it is transferred to the short-term memory = retrieval. 

Each has its own characteristics – encoding, capacity, duration. 

Sensory register 

Encoded = all sensory experience
Duration = 500 milliseconds// half a second 
Capacity = very huge 

Short term memory 

Encoded = mainly acoustic 
Duration = 30 seconds 
Capacity = 5-9 chunks 

Long term memory 

Encoded = mainly semantic – can be visual and acoustic 
Duration = unlimited 
Capacity = unlimited

ü Multistore model is that it gives us a good understanding of the structure and process of STM. Allows researchers to expand the model further. 
×     Short term memory and long term memory is more complex than the multistore model makes out. Supporting research from Baddeley and Hitch show that the short term memory store and long term is not a unitary store – compromising of different stores e.g. central executive, Visio-spatial.
×     Model suggests that rehearsal helps transfer information were we able that the 
ü Supported by research studies STM and LTM indeed qualitatively different. Baddeley, found we mix up words that sound the same when using STM. We mix upwards with similar meaning in LTM. Strength of study use acoustic coding in STM and LTM use semantic coding. Generated a lot of research.


*     Coding = Baddeley // given four groups // acoustically similar and dissimilar // semantically similar and dissimilar // asked to recall after hearing it (STM recall) tend to do worse with acoustically similar words. When asked to recall after 20 minutes (LTM recall) they did worse in semantically similar words. 
*     Capacity = Jacobs 1887 // digit span // 4 digits give to participants asked to recall these in correct order out loud. // if correct asked to read out 5 digits so on until the participants cannot recall order correctly // Jacob found the mean span to be 9.3 items and 7.3 letters. 
George Miller 1956 – span for short term memory is 7 items (+ or – 2) // also noted that through chunking people can recall 5 words as well as 5 recalling 5 letters. 
*     Duration = Peterson and Peterson // 24 undergraduate students tested // took part in 8 trials // trial = 1 test. // given a consonant syllable (trigram i.e. YCG) also given 3 digits // made to count backwards to prevent mental rehearsal of consonant syllable. // each trial told to stop after different amounts of time 3,6,7,9,12,15 or 18 seconds. = retential interval. // STM has short duration. // repeating = verbal rehearsal. 
Bahrick and colleagues 1975 – 392 participants American sstate ohio 17-74 // high school yearkbooks collected . recall was tested by 1) photo recognition – 50 photos from year book 2) free recall – recalled names of their graduating class 
Those tested within 15 years of graduation recalled 90% accurately in photo-recognition // 48 years recall decline to 70% for photo recognition. Free recall for 15 years after graduation 60% dropping 30% after 48 years. (LTM supportive evidence

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