1.2 memory Flashcards
memory
the process of retaining learned information and retrieving this information when needed. an important factor in how human beings process information.
processes in memory
coding, capacity, duration
coding
the way information is changed so that it can be stored in memory
coding case study (short term)
baddeley (1966) gave participants 4 lists of words to recall immediately:
SOUND:
A = similar sounding words
B = dissimilar sounding words
MEANING:
C = similar meaning words
D = dissimilar meaning words
he argued that stm is coded acoustically because participants performed better in list B than A suggesting similar sounding words can be confused. STM organises information according to how it sounds.
C and D had no difference (meaning is irrelevant to stm)
coding case study (long term)
baddeley (1966) repeated the experiment for ltm by delaying recall by 20 mins.
results showed that there was no difference between A and B this time (the sounds of the words didn’t affect memory).
participants performed better in word list D than C because ltm is coded semantically (organised based on meaning) so similar-meaning words could be confused.
evaluation for coding: baddely (1966)
+ lab experiment, so it is easy to replicate as the variables have been closely controlled. this means that reliability can be assessed.
- the results have low ecological validity. the material that participants needed to recall (lists of unconnected words) was artificial. in real life, people would never need to recall such information, meaning we dont know if memory is coded the same way outside the lab setting.
capacity
the amount of information that can be held in memory before new incoming information displaces it. this is when information is ‘pushed out’.
capacity case study (short term)
jacobs (1887) used a digit span test to determine the capacity of stm.
he gave participants several sequences of digits or letters, asking them to repeat the sequence immediately after in the correct order. sequences got longer by 1 each time.
results showed that on avg we can hold 9.3 digits and 7.3 letters. miller (1956) reviewed this and concluded that the span of stm was 7 (+/-) 2.
if we try to recall more information than we have the capacity for, it will displace old information.
he also found that we can recall five letters as easily as five words, so chunking (grouping large amounts of information into smaller groups) can help us remember more.
evaluation for capacity: jacobs (1887)
+ research was the first to acknowledge that stm capacity improves with age gradually
- study was done a long time ago (1887), so the validity is questioned. it may not have been done to the same scientifically vigorous standards as research today
capacity (long term)
the capacity of ltm is unlimited
duration
the amount of time information can be held in a memory store before it is lost due to decay - when information ‘fades away’
duration case study (short term)
peterson and peterson (1959) used nonsense trigrams (3 random consonants) to test STM duration.
they were asked to recall 3 random consonants that the psychologist had asked them in different time intervals.
they asked participants to count backward from 100 in 3s to prevent maintenance rehearsal (repeatedly verbalising or thinking about the information) during the time in between.
they found that recall was 90% accurate after 3 seconds, 20% after 9 seconds, and 2% after 18 seconds. this concludes that stm lasts for 18-30 seconds without rehearsal before it is lost due to decay.
evaluation for duration: peterson and peterson (1959)
+ high levels of control and standardised procedures because they made participants count down from 100 to prevent maintenance rehearsal and eliminated other factors like noise that could have influenced memory
- findings of the study may be caused by interference rather than stm having a short duration. possible that earlier learnt trigrams could be confused with later ones
duration case study (long term)
bahrick (1979) tested 400 people of various ages (17-74) on their memory of their classmates.
- a photo recognition test consisted of participants being shown 50 photos and deciding if they belonged to their classmates or not.
they found 90% accuracy at identifying faces of school friends within 15 years of leaving school. after 48 years this declined to 70%.
- a free recall test, participants were asked to list the names they could remember from their graduating class.
free recall of names of classmates was 60% accurate within 15 years of leaving school, dropping to 30% after 48 years.
bahrick et al. (1979) concluded that the duration of LTM is potentially a lifetime but sometimes we have retrieval failure and need retrieval cues to access this information.
evaluation for duration: bahrick (1979)
+ this study has higher ecological validity than peterson and peterson (1959) as the material used was more meaningful and relevant to everyday life.
- it is problematic to control for extraneous variables, such as people staying in touch after they left school or how many participants have looked in their yearbook since leaving school.
multistore model of memory
the MSM was developed by atkinson and
shiffrin (1968). it attempts to explain how information flows from one memory store to another.
there are three permanent structures in the memory system: the sensory register (SR), short-term memory (STM) and long-term memory (LTM).
each of these memory stores differ in terms of their capacity, duration, coding and how information is lost from them.
sensory register
environmental stimuli received through the senses enters the SR, which is a short-duration store that contains unprocessed impressions of information.
its coding is modality specific, which means that it has a separate sensory store for each sensory input, like the echoic store for auditory information, or iconic store for visual information
the capacity of the SR is unlimited, but its duration is only 250 miliseconds.
a small fraction of the information received by the SR is attended to and selected for further processing in STM. if not attended to, sensory information is lost due to decay.
short term memory
if information in the SR is attended to, it is acoustically coded into STM (that’s why similar-sounding material can be confused).
STM is a temporary store for information received from the SR before it is transferred to LTM. information may be recalled at this point and then forgotten.
STM has a limited capacity of 7 (+/-2) pieces of information so displacement with new information may occur. STM also has a short duration of 18-30 seconds. without rehearsal, information decays very quickly.
STM: rehearsal
there are two types of rehearsal.
maintenance rehearsal is repeatedly verbalising or thinking about the information, known as a rehearsal loop.
elaborative rehearsal is where information is organised in a meaningful way.
if there is sufficient or elaborative rehearsal, information may be transferred to LTM for more permanent storage
long term memory
if information is sufficiently rehearsed in STM then it is semantically coded into LTM. this is a permanent store holding limitless amounts of information for long periods.
the capacity of LTM is potentially infinite and there is no way of accurately measuring it. the duration of LTM could potentially be a lifetime.
when information in LTM is needed it is retrieved by STM and then recalled. sometimes we cannot access information from LTM because of retrieval failure so we may need retrieval cues to help us access it.
strength of MSM: scoville (1957)
+ scoville (1957) attempted to treat a patient’s (HM) epilepsy by removing several brain areas, including his hippocampus. this resulted in the patient being unable to code new long-term memories (LTM), although his short-term memory (STM) was unaffected. this supports the idea of separate and distinct STM and LTM.
strength of MSM: shallice and warrington (1970)
+ shallice and warrington (1970) reported the case study of KF.
because of a motorbike accident, he had a reduced STM capacity of one or two digits, but his LTM was normal. this supports the idea of separate STM and LTM stores.
- however, KF had poor STM for verbal tasks but not visual, suggesting there is more than one type of STM and that the MSM is flawed.
the MSM also suggests LTM has to be retrieved by the STM, but KF could do this without difficulty even with a damaged STM.
strength of MSM: murdock (1962)
+ murdock (1962) carried out the free recall experiment, in which participants were presented with a long list of words to be recalled in any order.
words at the beginning and the end of the lists were recalled better than those in the middle (serial position effect).
words at the beginning of the list are recalled because they have been constantly rehearsed and transferred to LTM (the primacy effect), while words at the end of the list are recalled because they are still in STM (the recency effect).
this supports the idea of separate and distinct STM and LTM
weakness of the MSM: over-simplified
- the MSM is oversimplified in assuming that there is only one type of STM and one type of LTM.
research studies indicate that there are several types of STM, such as one for verbal information (phonological loop) and another for non-verbal information (visuo-spatial sketchpad).
research also suggests that there are several types of LTM, we have episodic memory for life events, semantic memory for knowledge and facts and procedural memory for motor skills.
weakness of MSM: baddely and hitch (1974)
- they claimed that the MSM could not explain the ability to multi-task. if there is only one type of STM then multi-tasking would not be possible. however, people multi-task all the time, for example listening to the radio while driving.
working memory model
baddely and hitch (1974) questioned the idea promoted by the MSM that people only have one type of STM. they also argued that STM is more complex than just a temporary store for information before it is transferred to LTM.
they suggested the STM was an active store holding several pieces of information while they are being worked on, that is why they referred to their model as the working memory model.
they argued that LTM is the passive store that only holds previously learned material to be used by STM when needed.
the central executive
the central executive drives the whole working memory system and allocates data to the other components, known as slave systems.
it also deals with cognitive tasks such as decision-making, reasoning, and problem-solving.
since individuals have a limited attentional capacity, tasks that are automated make less attentional demands on the central executive and so leave us free to perform other tasks.
eg. a person who has been driving for 10 years will find that driving has become an automated task that does not make as many attentional demands as it did when they were learning to drive, and so they can now listen to the radio or talk to passengers much more easily than a learner driver can.
the phonological loop
the component of working memory that deals with spoken and written material. two sub-components.
the phonological store/inner ear: linked to speech perception. holds information in speech-based form (i.e. spoken words) for 1-2 seconds.
articulatory loop/inner voice: linked to speech production. used to rehearse and store verbal information from the phonological store. this allows for maintenance rehearsal.
visuo-spatial sketchpad
the visio-spatial sketchpad/inner eye is a component of the wmm that stores and processes information in a visual or spatial form. used for navigation. there are two subcomponents.
visual cache: stores visual material about form and colour
inner scribe: handles spatial relationships
the episodic buffer
baddeley (2000) added another component called the episodic buffer because he realised that the model needed a general storage component to operate properly.
this is because the slave systems only deal with the processing and temporary storage of specific types of information, and the central executive has no storage capacity at all.
the episodic buffer is a limited capacity store, integrating information from the central executive, the phonological loop, and the visuospatial sketchpad, as well as from LTM.
strength of WMM: shallice and warrington (1970)
+ shallice and warrington (1970) reported the case study of KF. because of a motorbike accident, he had poor STM for words that were presented verbally but not visually.
this suggests that there is more than one type of STM, as the WMM suggests. in particular, it shows that we have a type of STM for verbal tasks (phonological loop) and another for visual (visuo-spatial sketchpad).
strength of WMM: baddely and hitch (1974)
+ baddely and hitch (1974) gave participants a dual task. they were asked to complete a reasoning task (central executive), at the same time as a reading-aloud task (phonological loop).
participants could do both tasks simultaneously very well, supporting the idea of separate components in STM.
strength of WMM: baddeley (1975)
+ baddeley (1975) gave participants brief visual presentations of lists of words, either short or long words. participants were asked to recall the list immediately in the correct order.
it was found that participants could recall more short words than long ones. this is the word length effect.
he concluded that it supports the idea that the phonological loop can hold as many items as can be said in 1.5-2s rather than being limited by 7 (+/- 2) items as the MSM argues.
strength of WMM: practical applications
+ WMM has practical applications.
it has improved the understanding of how
people learn to read and so helped psychologists to assist those with dyslexia
who can struggle with reading.
weakness of WMM: damasio (1985)
- several psychologists have criticised the WMM because they think the idea of a central executive is vague and untestable.
damasio (1985) presented the case of EVR who had a cerebral tumor removed. he had good reasoning skills, which suggested his central executive was intact, but he could not make decisions, which suggests his central executive was damaged.
this case study strongly indicates that the central executive is more complicated than the WMM claims.
