memory Flashcards
coding definition
format in which information is processed and stored
capacity definition
amount of information that can be help in a memory store
duration definition
length of time information can be held in memory
coding baddeley
- lists of words to four groups of participants
- group 1 – acoustically similar (sound similar)
- group 2 – acoustically dissimilar
- group 3 – semantically similar (similar meaning)
- group 4 - semantically dissimilar
- participants asked to recall words in the same order
coding Baddeley findings
- immediate recall – recalling from short term memory tended to do worse in acoustically similar words
- recall after 20 minutes – recalling from long term memory did worse with semantically similar words
coding baddeley advantage
- separate memory store - identified a clear difference between 2 memory stores, led to multi store memory model
coding baddeley disadvantage
- artificial stimuli - word list had no personal meaning to participants, processing more meaningful information may use semantic coding even for STM tasks.
capacity jacobs
- participants asked to recall the list the correct order until they make an error
- mean score = 9.3
- letter = 7.3
capacity miller
- magic number = 7
- believed that STM capacity is 7 +/- 2
capacity advantage
- valid study - has been replicated (Bobb and Verhaegen)
capacity disadvantage
not so many chunks
- may have overestimated STM capacity
- cowan reviewed research and found capacity of STM is only about 4
- suggests lower end of miller estimate is more appropriate than 7 items
duration Peterson and Peterson
- 24 student participants in 8 trials/tests
- students had to remember a consonant syllable (trigram) and count 3 digit number to count back from
- prevent any mental rehearsal of consonant syllable
- asked to stop for different periods of time from 3-18 seconds
duration Peterson and Peterson findings
- After 3 seconds the average recall was 80%
- After 18 seconds the average recall was 3%
duration Baharick
- 392 american participants aged 17-74
- tested photo recognition and free recall from highschool yearbook
duration Baharick findings
- <15 year graduation 90% photo, 60% free
- 48 years, 70% photo, 30% recall
duration positives
high external validity
- research investigated meaningful memories
- when studies on LTM were conducted with meaningless pictures recall rates lower
- suggests findings reflect a more real estimate of duration of crime
duration negatives
artificial stimuli
- rather than meaning full material
- word list had no personal meaning
- findings may not tell us much ab coding in different kinds of memory tasks
- processing more meaningful information people may use semantic coding even for STM tasks
Factors affecting the accuracy of eyewitness testimony: misleading information
Loftus and Palmer
Loftus and Palmer
- 45 participants to watch clips of car accidents
- asked to describe how fast the cars were going, 5 groups given different verb
- mean for ‘contacted’ was 31.8mph
- mean for ‘smashed’ was 40.5mph
why do leading questions affect EWT
response bias
- wording of questions influence how we answer
- Loftus and palmer - participants who heard ‘smash’ recalled broken glass (there was none)
research on post-event discussion
Gabbert
- each participant watched video of same crime but filmed from different angle
- then discussed what they saw before completing recall test
- 71% recalled aspects that they heard in discussion not in video
- control group where no discussion was 0%
why does post-event discussion affect EWT
- memory contamination - co-witnesses to crime discuss it eyewitness testimony become altered, they combine info with other witnesses with their own
- memory conformity - Gabbert witnesses go along with each other to win social approval
misleading information evaluation
- real world application
- evidence against the substitution
- evidence challenging memory conformity
misleading information real life application
real world application
- in criminal justice system
- Loftus - leading questions have distorting effect on memory so police are careful with how they phrase their questions
- psychologists askd to act as eyewitnesses in court to explain the limits of EWT to juries
real world application counterpoint
- Participants watched film clips in a lab different from experiencing it in real life
- Foster said what eyewitnesses remember has important consequences in the real world but participant responses in research don’t matter in the same way
- Suggests that Loftus is too pessimistic about the effects of misleading information
misleading information.
evidence against the substitution
- EWT is more accurate for some aspects of an event than others
- Sutherland and Hayne - asked leading questions their recall was more accurate for central details
- original memories for central details survived and were not distorted an outcome that is not predicted by the substitution explanation
misleading information.
evidence challenging memory conformity
- Evidence that post – event discussion actually alters EWT
- Skagerberg and Wright (2008) showed participants 2 versions film clips.
- Participants discussed the clips in pairs each having seen different
- Often didn’t report what they had seen but what they had heard
- Suggests that memory itself is distorted through misleading post-event discussion rather than result of memory conformity.
improving the accuracy of EWT: cognitive interview
Fisher and Geiselman
- EWT could improve if police used cognitive interviews
cognitive interview
method of interviewing eyewitnesses to help them retrieve more accurate memories
- 4 main techinques used
cognitive interview
4 main techniques used
- report everything
- reinstate the context
- reverse the order
- change perspective
the enhanced cognitive interview
- Fisher - focus on dynamics of the interaction
- includes ideas such as reducing eyewitness anxiety, mimimising distractions
cognitive interview positive
support for the effectiveness
- Meta- analyse by kohnken, combined data from 55 studies comparing the CI with the standard police interview
- CI gave an average 41% increase in accurate information
- Shows CI is an effective technique in helping witnesses recall information that is stored in the memory but not immediately accessible
cognitive interview negative
some elements may be more useful
- not all elements are useful
- Milne and Bull- found combining ‘report everything’ and ‘reinstate the context’ produced the best recall
- some aspects of CI are more useful than others
cognitive interview negative
time consuming
- police may reluctant to use CI because it takes more time and training
- better to focus on just a few elements
the multi store memory model
- representation of how memory works in terms of 3 stores
- Describes how information is passed from 1 store to another
sensory register
- All stimuli from the environment is passed into the sensory register
- Memory store for each of our 5 senses
- Coding in each store is specific
- Duration less than half a second
- high capacity
- Information passes further into the memory system only if you pay attention to it
STM
- Coded mainly acoustically and lasts around 18 seconds unless its rehearsed
- Temporary memory store
- Capacity is between 7 +/-2
LTM
- Potentially permanent memory store for information that has been rehearsed for a prolonged time
- Coded mostly semantically
- when we want to recall information from LTM it has to be transferred back into STM by retrieval
- Bahrick el al found many participants were able to recognise the names and faces of old school classmates almost 50 years after graduating
multi store memory model evaluation
- research support
- more than 1 STM store
-elaborative rehearsal
research support
- MSM shows that STM and LTM are different
- Baddeley found we tend to mix words that sound similar when using our STM
- mix words that have similar meaning when we use our LTM
- Shows LTM and STM are separate independent memory stores, claimed by the MSM
research support counterpoint
- In everyday life we form memories related to all sorts of useful things – names, faces
- many studies that support MSM used none of these materials
- Used digits, letters (Jacob) and sometimes words (Baddeley)
- Used consonant syllables – have no meaning
- Means that MSM may not be valid model of how memory works in our everyday life where we have to remember meaningful information
more than 1 STM store
- Shallice and Warrington studied a client with amnesia
- STM for digits was poor when read aloud to him but good when he read them himself
- Shows MSM is wrong in claiming that there is just 1 STM store processing different types of information.
elaborative rehearsal
- Prolonged rehearsal isn’t needed to transfer to LTM
- according to MSM what matters about rehearsal is the amount of it (the more you rehearse something the more likely it goes to your LTM) – prolonged rehearsal
- Craik and Watkins found the type of rehearsal is more important than the amount
- elaborative rehearsal is needed for long-term storage
- occurs when you link information of existing knowledge
- suggests MSM doesn’t fully explain how LT storage is achieved
types of LTM
- Tulving proposed the idea that there are 3 LTM stores
episodic memory
- Recall person events from life
- Memories are time stamped
- Memories of single episode will include several elements (people, places, objects)
- Memories have to be retrieved consciously and with effort