2. memory Flashcards
short-term memory
the limited capacity memory store
― coding is mainly acoustic
― capacity is between 5 and 9 items
― duration is about 18 seconds
long-term memory
the permanent memory store
― coding is mainly semantic (meaning)
― has unlimited capacity
― can store memories for up to a lifetime
coding
the format in which information is stored in the various memory stores
capacity
the amount of information that can be held in a memory store
duration
the length of time information can be held in memory
research on coding
Baddeley procedure & findings
Alan Baddeley gave different lists of words to four groups of participants to remember
➥ group one: acoustically similar
➥ group two: acoustically dissimilar
➥ group three: semantically similar
➥ group four: semantically dissimilar
― Participants were shown the original words and asked to recall them in the correct order
― When they did this task immediately, recalling from STM, they tended to do worse with acoustically similar words
― When they recalled the world list after a time interval of 20 minutes, recalling from LTM,** they did worse with the semantically similar words**
― These findings suggest that information is coded acoustically in STM and semantically in LTM
research on capacity
Jacobs - digit span procedure and findings
Joseph Jacobs found out how much information can be held by STM at one time by measuring digit span
― The researcher reads out four digits and the participant recalls these aloud in the correct order.
― If this is correct the researcher reads out five digits and so on until the participant cannot recall the order correctly.
➥ this indicates the individual’s digit span
― Jacobs found that the mean span across all participants was 9.3 but the mean span for letters was 7.3
research on capacity
George Miller - span of memory and chunking and findings
George Miller made observations of everyday practice
― For example he noted that things come in sevens: seven notes on the musical scale, seven days of the weel, seven deadly sins, etc.
― He thought that the span of STM is about 7 items, plus or minus 2
― He noted that people can recall five words as easily as they can recall five letters.
― We do this by chunking (grouping sets of digits or letters into units or chunks)
research on duration
Peterson and Peterson - duration of STM procedure and findings
Margaret and Lloyd Peterson tested 24 students in eight trials each
― On** each trial, the student was given a consonant syllable** (e.g. YCG) to remember as well as a three-digit number
― The student counted backwards from this number until told to stop
➥ the counting backwards was to prevent any mental rehearsal of the consonant syllable
― After each trial they were told to stop after varying periods of time (3, 6, 9, 12, 15, or 18 seconds)
― After three seconds, average recall was about 80%; after eighteen seconds, it was about 3%
― These findings suggested that STM duration without verbal rehearsal may be about 18 seconds
research on duration
Bahrick - duration of LTM procedure and findings
Henry Bahrick et al. studied 392 American participants between 17 and 74.
― High school yearbooks were obtained from the participants or directly from some schools
― Recall was tested in various ways
➥ a photo-recognition test consisting of 50 photos, some from the participants’ high school yearbooks
➥ free recall test where participants recalled all the names of their graduating class
― Participants tested within 15 years of graduation were about 90% accurate in photo recognition.
― After 48 years, recall declined to about 70% for photo recognition
― Free recall was less accurate than recognition
➥ 60% after 15 years; 30% after 48 years
― This shows that LTM may last up to a lifetime for some material
multi-store model
― A representation of how memory works in terms of three stores (the sensory register, STM, and LTM)
― It also describes how information is transferred from one store to another, what makes some memories last or disappear
linear MSM model
information is shown to flow through the system in one direction
passive stores
the stores hold on to information before being passed on or lost
sensory register
― This store is not under cognitive control like STM or LTM.
― All information found in the STM or LTM stores were initially gathered by the sensory register.
― Information is passed on to STM by paying attention.
coding
sensory register
The store depends on the sense organ the information comes from
➥ visual information is iconic; acoustic information is echoic
capacity
sensory register
The SRs have a very high capacity
➥ over one hundred million cells in one eye, each storing data
duration
sensory register
― It is very brief, less than half a second
― As so much information is held, it cannot be retained for very long
multi-store model
short term memory
― STM passes information to LTM through rehearsal.
― This is either maintenance rehearsal or elaborative rehearsal.
― Information is passed back from LTM with retrieval, and information can be lost via displacement or decay
coding
short term memory
Information in short term memory is stored acoustically (in the form of sound / spoken words)
capacity
short term memory
Miller suggested that this is small between 5 and 9 items of information and this can be improved by chunking
➥ Cowan’s research, however, suggested that it might be more like five rather than nine.
duration
short term memory
Short, between 18 and 30 seconds.
➥ However, the duration of information can be extended by maintenance rehearsal
multi-store model
long term memory
― Information stored may last permanently and LTM may be unlimited in the amount of information it can contain
― Information comes into LTM from STM via rehearsal
― In order to use information in LTM, it needs to be passed back to STM via retrieval
coding
long term memory
Information in long term is stored semantically
➥ this is in the form of meaning
capacity
long term memory
Capacity is thought to be unlimited
― Information can be lost but doesn’t seem to be because it is ‘out of the room’
➥information may still be in LTM but not accessible
duration
long term memory
Psychologists believe that is potentially unlimited.
➥ Recall of childhood events is normal even for the oldest people
multi-store model strengths (AO3)
support from research - Alan Baddeley
One strength of the MSM is support from studies showing that STM and LTM are different
― For example, Alan Baddeley found that we tend to mix up words that sound similar when using our STM; and that we mix up words that have similar meanings when we use our LTMs
― These studies clearly show that STM and LTM are separate and independent memory stores, as claimed by the MSM
multi-store model limitations (AO3)
evidence of more than one STM store & elaborative rehearsal
One limitation of the MSM is** evidence of more than one STM store.**
― Tim Shallice and Elizabeth Warrington studied a client they refered to as KF
➥ KF had amnesia, a clinical memory disorder.
― KF’s STM for digits was very poor when read out loud to him, but his recall was much better when he read the digits to himself.
― Further studies of KF showed that there could even be another short-term store for non-verbal sounds
― This evidence suggests that the MSM is wrong in claiming that there is just one STM store processing different types of information
Another limitation of the MSM is that prolonged rehearsal is not needed for transfer to LTM
― According to the STM, what matters about rehearsal is the amount of it
➥ the more you rehearse something, the more likely it is to transfer to LTM (prolonged rehearsal)
― Fergus Craik and Michael Watkins found that the type of rehearsal is more important than the amount.
― Elaborative rehearsal is needed for long-term storage. This occurs when you link the information to your existing knowledge, or you think about what it means.
➥ this means that information can be transferred to LTM without prolonged rehearsal
― This suggests that the MSM does not fully explain how long-term storage is achieved.
