memory Flashcards
what is short term memory?
a limited capacity memory store, coding is mainly acoustic, capacity is between 5-9 items and the duration is about 18 seconds
what is long term memory?
a permanent memory store, coding is mainly semantic, has unlimited capacity that can store for up to a lifetime
what is coding?
the way in which information is stored in various memory systems
what is capacity?
the amount of information that can be stored
what is duration?
how long memories can be stored
what was the procedure for Alan Baddeley’s research on coding?
- gave different lists of words to four groups of participants
group 1: (acoustically similar)
group 2: (acoustically dissimilar)
group 3: (semantically similar)
group 4: (semantically dissimilar)
- participants were shown the original words and asked to recall them in the correct order.
what were the results of Baddeley’s research on coding?
- When they immediately recalled from the STM, they struggled the most with acoustically similar words
- When they recalled the words after 20 mins, with their LTM, they did worse on semantically similar words
- these findings suggest that STM is acoustically coded and LTM is semantically coded
strength of Baddeley’s research into coding - separate memory stores
- identified a clear difference between the two memory stores
- although later research showed some exceptions, these ideas have stayed the same over time
- this was important in understanding the memory system and understanding the MSM
weakness of Baddeley’s research into coding - artificial stimuli
- used artificial stimuli instead of meaningful
-Baddeley’s findings do not tell us about memory tasks in everyday life - when people are using memory in everyday life, they may use semantic memory even in STM
- this suggests that the findings from the study have limited application
How did Jacobs (1887) find about capacity?
- began measuring digit span e.g how many digits the participant can recall at once is their capacity
- found that the mean span for digits was 9.3 and for letters it was 7.3
how did George Miller (1956) find out about capacity?
- noted different things come in sevens and thought that the span of the STM is 7 + or - items
- found that by chunking, people have the capacity they can recall 5 words as easily as letters
strength of Jacob’s study of capacity - a valid study
- has been replicated
- the study is very old and old studies often lack adequate controls on variables
-despite this, Jacob’s findings have been confirmed by more recent, better controlled studies - this hows that Jacob’s study is valid
weakness of Miller’s study on capacity - not so many chunks
- one limitation is Miller may have overestimated STM capacity
- Cowan (2001) reviewed other research and suggested that capacity may only be 4 + or - 1 chunks
- this suggests the lower end of his estimate may be more correct
what happened in Peterson and Peterson (1959) study on STM duration?
- laboratory test on 24 psychology students in 8 trials
- in each trial, they were given trigrams to recall at different intervals, counting backward
- told to stop at 3,6,9,12,15 or 18 seconds) (retention interval)
what were the findings of Peterson and Peterson (1959) study on duration?
- after 3 seconds recall was 80%, after 18 seconds it was 3%
- concluded that information vanishes rapidly from STM if participants are not able to rehearse information, duration is about 18 seconds
what was the procedure of Bahrick et al (1975) study into duration of LTM?
- studied 392 american participants between the ages of 17 and 74 where they obtained their yearbooks
they tested their recollection of the people through photos and free recall with their names
what were the findings of Bahrick et al (1975) ?
-those tested within 15 years were 90% accurate in photo recall
- after 48 years, recall declined to about 70% for photo recall
- free recall has 60% accuracy after 15 years, dropping to 30% after 48 years
- this shows that LTM may last up to a lifetime for some material
limitation of Peterson and peterson (1959) - stimulus material was artificial
- the study is not completely irrelevant as we may try to remember meaningless ideas
- recalling trigrams does not appear in everyday life
- lacks external validity
strength of Bahrick et al (1975) - high external validity
- the researchers investigated meaningful memories
- when studies on LTM were conducted with meaningless pictures to be remembered, the recall rate was not as high (Shepard 1967)
- this suggests that Bahrick et al’s study reflects a more realistic viewpoint on LTM
describe Atkinson and Shiffrin (1968) multiple store model
information enters the sensory store and through attention enters the STM. it stays in the STM by rehearsal and can be transferred to the LTM through transfer. It either stays in the LTM or through retrieval can go to the STM. it can be forgotten or decay at any time
strength of MSM - research support
- one strength of the MSM is support from studies that show that STM and LTM are different
- for example , Baddeley found that we tend to mix up words that sound similar when we are using our STM, but we mix up words that tend to have similar meaning of capacity and duration
couterpoint of a strength of MSM - research support isn’t as valuable
- in everyday life, we form memories related to all sorts of things, something that is not shown in experiments as they often use digits
- this means that the MSM may not be as applicable and valid to everyday life as we thought
weakness of MSM - more than one STM store
- one limitation of the MSM is the evidence of more than one STM store
- Tim Shallice and Elizabeth Warrington (1970) studied KF, who had amnesia from a brain injury
- KF’s STM for digits was poor when they were read aloud to him but he was much better when he read the digits himself
- this means that there may be more than one form of STM
weakness of MSM - elaborative rehearsal
- another limitation of the MSM is prolonged rehearsal is needed for the transfer to the LTM
- MSM says that the more you rehearse something, the more likely it is to transfer to LTM (prolonged rehearsal)
- Fergus Craik and Michael Watkins (1973) 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)
- this means that information can be transferred to the LTM without prolonged rehearsal
- this suggests that the MSM does not fully explain how long term storage is achieved
how does the case of HM support MSM?
- HM went under brain surgery to relive his epilepsy
- his hippocampus was removed from both sides of his brain
- when his memory was assessed in 1955, he though that the year was 1953 and that it was 1953
- he could not form long term memories and would read things multiple times without realising
- despite this he performed well on tests of STM
- individual case study but good real life example
how does Sperling (1960) support the limited duration of the sensory register?
- tested the iconic sensory register (memory store)
- participants saw a grid of digits and letters for 50 milliseconds
- they were asked to either write down all 12 items or they would hear a tone immediately and after the exposure, they should write down the row indicated
- when asked to report the whole thing, their recall was poor
who proposed the idea of multiple LTM and why?
Tulving (1985) and he said that the MSM was too simplistic and inflexible
what is episodic memory?
- our ability to recall events (episodes) from our lives
- these memories are complex and time stamped
- you have to make a conscious effort to recall
what is semantic memory?
- shared knowledge of the world
- knowledge of concepts and are not time-stamped
- less vulnerable to distortion and forgetting
- conscious recall
what is procedural memory?
- memory for actions or skills
- can recall without concious effort
- hard to explain to someone else
strength of types of LTM - clive wearing and HM
- episodic memory in both cases was severely impacted due to brain but their semantic and procedural memory was still intact
- this evidence supports Tulving’s ideas that there are different LTM memory stores
counterpoint for clive wearing and HM
- there is often very little control of extraneous variables due to accidents being unexpected
- there is no knowledge on the memory before the accident
- this lack of control limits what clinical studies can tell us about different types of LTM
limitation of types of LTM - conflicting neuro imaging research
- Randy Buckner and Steven Peterson (1996) reviewed evidence regarding the location of semantic and episodic memory
- they concluded that semantic memory is located on the left side of the prefrontal cortex and episodic memory on the right
- however different research says that the left pre frontal cortex is for episodic encoding and the right is for episodic retrieval
- this conflict challenges any neurophysical evidence
strength of LTM - real world application
- allows psychologists to help people with memory problems
- for example, as people age, they experience memory loss - research has shown that this is specific to episodic memory
- Belleville et al 2006 devised an intervention to improve the memory of elderly people - experiment group had better memory after training than the control group
what is the WMM (working memory model) (Baddeley and Hitch 1974)
an explanation of how one aspect of STM is organised and how it functions
what is the job of the Central executive
- has a “supervisory role”
- monitors incoming data, focuses and divides our limited attention, and allocated tasks to subsystems
- has a very limited capacity and does not store information
what is the job of the phonological loop?
- Processes information in terms of sound
- This includes both written and spoken material
- It’s divided into the phonological store (stores the words you hear) and the articulatory process (allows maintenance rehearsal)
- Capacity of this loop is believed to be two seconds worth of what you can say
