Memory Flashcards
(36 cards)
What is coding?
The process of converting information from one format to another. Once information gets into the memory system, it’s stored in different formats, depending on the memory store.
How did Baddeley (1966) study coding?
A - investigated coding used in STM and LTM.
M - 4 groups of participants were each shown a different list of words to memorise. Group 1 were given acoustically similar words, Group 2 acoustically dissimilar words, Group 3 semantically similar words and Group 4 semantically dissimilar words. Participants were asked to recall them in the correct order. Some were asked to do this immediately after (coding in STM) and others were asked to recall 20 mins later (coding in LTM).
R - when asked to recall immediately, participants recalled fewer words in the correct order with acoustically similar words. When asked to recall after 20 mins, fewer semantically similar words were recalled correctly.
C - information is coded acoustically in STM and semantically in LTM.
What is capacity?
A measurement of how much information a memory store can hold. One way of measuring the capacity of STM is using the digit span task (Jacobs, 1887).
How did Jacobs (1887) study capacity?
Digit span task - the researcher gives participants a list of digits (numbers from 0 through 9) and then the participant is asked to recall these in the correct order. If they are correct, the researcher gives the participant another list but with one more digit than the last one and asks them to recall in the correct order. The researcher continues to add one digit to each proceeding list until the participant cannot recall the order correctly. This determines the individual’s digit span. Jacobs found that the mean span for digits across all participants was 9.3 items. When repeated with letters rather than digits, Jacobs found the mean span for letters was
7.3.
How did Miller (1956) study capacity?
From Jacobs’ research, Miller (1956) proposed that the span (or capacity) of STM is around 7 items (plus or minus 2). This was reinforced by everyday observations, where Miller noted that things tend to come i sevens such as seven notes on the musical scale, seven days of the week, seven deadly sins etc.
Miller also noted that people can recall 5 words as well as they can recall 5 letters and identified chunking as the process they used. Chunking is where we group together sets of digits or letters into units or chunks.
What is duration?
A measurement of how long a memory store can hold information for.
How did Peterson and Peterson (1959) study duration in STM?
A - to investigate the duration of STM.
M - tested 24 undergraduate students who each took part in 8 trials. On each trial, the student was given a trigram to remember and was also given a 3-digit number. The student was then asked to count backwards from that number until told to stop. This was to prevent any mental rehearsal of the trigram. On each trial, they were told to stop counting backwards after a different amount of time (either 3, 6, 9, 12, 15 or 18 seconds - retention interval).
R - they found that the number of trigrams recalled significantly decreased as the retention interval increased and after the 18 second retention interval, only 10% of the trigrams were successfully recalled. (Negative correlation.)
C - this suggests that STM may have a very short duration of around 18 seconds unless we repeat something over and over again (maintenance rehearsal).
How did Bahrick et al (1975) study duration in LTM?
A - to investigate the duration of LTM.
M - studied 392 participants from the American state of Ohio who were aged between 17 and 74. High school yearbooks were obtained from the participants or directly from some schools. Recall was tested in various ways including:
(1) photo-recognition test consisting of 50 photos, some from the participant’s high school yearbook.
(2) free recall test where participants recalled all the names of their graduating class.
R - participants who were 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 worse than recognition. After 15 years, this was about 60% accurate, dropping to 30% after 48 years.
C - the duration of LTM is very long and at least 48 years.
(-) Artificial stimuli evalutation for Baddeley’s study into coding (1966).
One limitation of Baddeley’s study is that it used artificial stimuli rather than meaningful material. The word lists had no personal meaning to participants. This means we should be cautious about generalising the findings to different kinds of memory task. For example, when processing more meaningful information, people may use semantic coding even for STM tasks. This suggests that the findings from this study have limited application and low external validity.
(-/+) Lacking internal validity evalutation for Jacobs’ study into capacity (1887).
One limitation for Jacob’s study is that it was conducted a long time ago, in 1887. Early research in psychology often lacked adequate control. For example, some participants may have been distracted while they were being tested so they didn’t perform as well as they might. This would mean that the results might not be valid because there were confounding variables that were not controlled. (+) However, the results of this study have been confirmed in other research, confirming their reliability and meaning that they are more likely to be valid.
(-) Not so many chunks evalutation for Miller’s research into capacity (1956).
One limitation of Miller’s research is that he may have overestimated the capacity of STM. For example, Cowan (2001) reviewed other research and concluded that the capacity of STM was only about 4 chunks. This suggests that the lower end of Miller’s estimate (5 items) is more appropriate than 7 items.
(-/+) Meaningless stimuli evalutation for Peterson and Peterson’s study into duration in STM (1959).
A limitation of Peterson and Peterson’s study is that the stimulus material was artificial. Trying to memorise consonant syllables does not reflect both real-life memory activities where what we are trying to remember is meaningful so may lack ecological validity. (+) However, we do sometimes try to remember fairly meaningless things, such as phone numbers, so it could be argued that the study does have some ecological validity.
(+) Higher external validity evalutation for Bahrick et al’s study into duration in LTM (1975).
One strength of Bahrick et al’s study is that it has higher external validity. Real-life meaningful memories were studied. When studies on LTM have been conducted with meaningless pictures to be remembered recall rates were lower (Shepard, 1967). The downside of such real-life research is that confounding variables are not controlled, such as the fact that Bahrick’s participators may have looked at their yearbook photos and rehearsed their memory over the years.
What is Atkinson and Shiffrin’s Multi-Store Model (1969)?
The MSM attempts to explain the flow of information through three separate memory stores, from input to storage. It is a good example of the ‘information processing approach’ in psychology, seeing cognitive processes as a sequence of stages and comparing them with the operations of a computer.
It’s a linear model that sees STM and LTM as functionally different from each other.
What is the coding of the sensory registers like in MSM?
Sensory information from the environment is first encoded into the sensory registers.
There is a sensory register for each of our 5 main senses and each is modality specific i.e. they encode information in the same code which they receive it. For example, the iconic memory receives visual information from our eyes and encodes that information visually - based on what it looks like. The echoic memory receives auditory information from our ears and encodes this information acoustically - based on what it sounds like.
What are the capacity and duration of the sensory registers like in MSM?
Quite large capacity.
Very brief duration of less than half a second.
Most information in sensory memory is lost when the brief memory trace fades.
Information we pay attention to is passed to STM.
What are the capacity and duration of STM like in MSM?
STM is your memory for immediate events. This is a temporary place for storing information and has a limited duration of 18-30 seconds (if not rehearsed) and a limited capacity of between 5 and 9 items (Miller, 1956).
Chunking can also be used to expand the capacity of this store.
What is maintenance rehearsal for STM in MSM?
It is possible to maintain information in STM for longer than 30 seconds by repeating information over and over again which is called maintenance rehearsal. For example, verbally rehearsing a set of directions in your head as you follow a route in a car.
Maintenance rehearsal is also the process by which we pass information into LTM - if we repeat information for long enough it will pass into LTM.
What is LTM like in MSM?
Long term memory is a relatively permanent store and has a possibly unlimited capacity and a large duration - possibly up to a lifetime.
When we want to recall information from LTM it is transferred back into STM by a process called retrieval. No memories are recalled directly from LTM.
How can the case of HM be used to support the MSM?
HM underwent experimental brain surgery for epilepsy.
During the surgery, his hippocampus was removed from both sides of his brains, which we have since learnt is involved in memory function.
When HM was questioned in 1955 at the age of 31, he believed it was 1953 and he was 27. HM couldn’t recall the operation and couldn’t remember speaking to someone an hour earlier.
HM’s LTM was repeatedly tested but never improved even with practice eg. he couldn’t remember reading a particular magazine or what he had for lunch earlier that day. However, he did perform well in tests involving STM where he had to recall things from the last few seconds.
This clearly supports the MSM as it gives evidence that STM and LTM must be separate stores as in HM, although his LTM was damaged, his STM remained functioning.
(+) Research support evaluation for MSM - Baddeley (1966).
The MSM is supported by research studies that show that STM and LTM are qualitatively different eg.
Baddeley (1966) found that we tend to mix up words that sound similar when we are using STM, but we mix up words that have similar meanings when using LTM. This study clearly shows that coding in STM is acoustic and in LTM it is semantic which implies they are different and thus supports the MSM’s view that these two memory stores are separate and independent. (+) Further reliable support is given by all the studies of coding, capacity and duration.
(+) Research support evaluation for MSM - Squire et al (1992).
Further research from brain scanning techniques has supported the MSM and the idea of separate memory stores (ie. a STM store and a LTM store). Squire et al (1992) used brain-scanning techniques and found that STM can be associated with activity in the prefrontal cortex and that LTM can be associated with activity in the hippocampus. This is a strength because it provides biological evidence that the different types of memory are processed by different parts of the brain and that the memory stores are distinct as the MSM suggests.
(-) Contradictory evidence evaluation (STM isn’t a unitary store) for MSM - Shallice and Warrington (1970).
The MSM states that STM is a unitary store (ie. there is only one type of STM). However, evidence from people suffering a clinical condition called amnesia shows that this cannot be true. Shallice and Warrington (1970) studied a patient with amnesia known as KF. They found that KF’s short-term memory for digits was very poor when they read them out loud to him. But his recall was much better when he was able to read the digits for himself. This suggests that at the very least, there must be one short-term store to process visual information and another one to process auditory information weakening the MSM’s idea that STM is unitary. An improvement to the MSM can be seen in the working memory model which includes these separate stores.
(-) Contradictory evidence evaluation (more than one type of rehearsal) for MSM - Craik and Watkins (1973).
According to the MSM, the more you rehearse information, the more likely you are to transfer it to LTM and remember it for a long time. However, Craik and Watkins (1973) found that this prediction is wrong and found that what really matters about rehearsal is the type. They discovered that there are two types of rehearsal:
Maintenance rehearsal - (+) maintains (increases the duration of) information in STM (which supports the MSM). (-) However, Craik and Watkins (1973) found that this does not transfer information into LTM (which contradicts the MSM).
Elaborative rehearsal - transfers information into LTM by either linking the information to your existing knowledge, or by you thinking about the meaning of the information (not present in the MSM which suggests it is incomplete and inaccurate).
