Memory 🧠 Flashcards
(88 cards)
What is the capacity of STM?
STM is limited and Joseph Jacob’s (1887) found capacity by measuring digit span eg when researcher reads out four digits and the participant recalls these out loud in order correctly.
- If correct researcher reads out five digits and so on until participant can’t recall order correctly- indicates individuals digit span
He found that the mean span for digits across all participants was 9.3 items. Mean span for letters was 7.3
What is the span of memory and chunking (STM)?
George Miller(1956) made observations of everyday practice eg he noted things that came in sevens like days of the week etc
- Miller thought the span of STM was about 7+-2 items
- also noted that people recall five words as easily as they can recall five letters by chunking - grouping sets of digits or letters into units or chunks
LTM = UNLIMITED
What is the duration of STM? (Peterson and Peterson process)
length of time info can be held for
Peterson and Peterson (1959) :
- 24 students took part in 8 trials each
- given a consonant syllable to remember
- given a 3 digit number to count back from in 3s until told to stop to prevent rehearsal in head
- each trial saw the backwards counting last a different time (3,6,9,12,15 or 18 seconds) - retention interval
What did Peterson and Peterson find?
- After 3 seconds average recall was about 80%
- After 18 seconds= 3%
- Their findings suggested that STM duration may be about 18 seconds unless we repeat the info over and over ( mental rehearsal)
Duration= between 18 and 30 seconds
What is the duration of LTM? (Bahrick et al)
Bahrick et al (1975) studies 392 American participants aged between 17 and 74 and high school year books were obtained from participants or schools
- Recall was tested in photo recognition a test consisting of 50 photos some from participants year books
- also through free recall test in which participants recalled all names from graduating class
What did Bahrick et al find?
- Particpants tested within 15 years of graduation = 90% accurate in photo recognition
- After 48 years, recall declined to about 70% for photo recognition
- Free recall was less accurate than recognition - about 60% after 15 years dropping to 30% after 48 years
Shows that LTM may last up to a lifetime for some material
What is coding?
the format in which info is stored in different memory stores
What are the different types of coding?
acoustic= sound
semantic = meaning
What was Baddely’s (1966) experiment process?
He gave different lists of words to four groups of participants ( acoustically similar words, acoustically dissimilar words that sound different, semantically similar and semantically dissimilar)
What did Baddely find?
- Participants were shown original words and asked to recall in correct order and when they did this task immediately recalling from STM they tended to do worse with acoustically similar words
- When they recalled the list after 20 mins recalling from LTM they did worse with the semantically similar words
Information is coded acoustically in STM and semantically in LTM
What is a strength of Jacob’s capacity study?
P- One strength of Jacob’s study is that it’s been replicated
E- The study is very old and early research in psychology often lacks adequate controls eg some participants digit spam might have been underestimated because they were distracted during testing(confounding variable). Despite this Jacob’s findings have been confirmed by other better controlled studies since such as Bopp and Verhaghen (2005).
L- This suggests that Jacob’s study is a valid test of digit span in STM.
What is a limit of Miller’s capacity study?
P- One limitation of Miller’s study research is that he may have overestimated STM capacity.
E- Nelson Cowan 2001 reviewed other research and concluded that the capacity of STM is only about 4+-1 chunks.
L- This suggests that the lower end of Miller’s estimate (5 items) is more appropriate than 7 items.
What is a limit of Peterson and Peterson study on duration of STM?
P- One limitation Peterson and Petersons study is that the stimulus material was artificial.
E- The study isn’t completely irrelevant as we do sometimes try to remember fairly meaningless material eg phone numbers. However recalling consonant syllable doesn’t reflect most everyday memory activities where what we’re trying to remember is meaningful.
L- This means the study lacked external validity.
What is a strength of Bahrick’s study on duration of LTM?
P- One strength of Bahrick et als study is that it has high external validity.
E- This is because researchers investigated meaningful memories (people’s names and faces). When studies on LTM were conducted with meaningless pictures to be remembered recall rates were lower eg Shepard (1967).
L- This suggests that Bahrick et al’s study findings reflect a more real estimate of the duration of LTM.
What is the sensory register? (multistore model)
- receives any info
- two main stores within is the iconic memory where visual info is coded and echoic memory which is where auditory info is coded acoustically.
- The duration= only half a second
- very high capacity as there are millions of sensory cells storing data
- for its info to be passed on to STM attention must be paid to it
LTM in multi store model of memory
- If info is rehearsed enough it becomes LTM (prolonged rehearsal)
- unlimited capacity and duration could last a lifetime
- Bahrick et al’s (1975) study showed people could identify their classmates 50 years after leaving school
- coded semantically so given meaning
- If we want to recall info from LTM retrieval from LTM back into STM must occur
- memories are not recalled directly from LTM
STM in multistore model
- only holds specific capacity before info is lost
- 7+-2 items but research suggests it’s closer to 5 than 9
- coded acoustically and won’t last more than 30 seconds
- maintenance rehearsal - when we repeat the info over and over in heads to keep it in STM
What is a strength for the multi store model?( famous case study)
P- Henry Gustav Molaison (HM) is a famous case of anterograde and retrograde amnesia in psychology.
E- He underwent brain surgery to remove his hippocampus and amygdala to control his seizures and as a result the seizures decreased but he could no longer form new long term memories or remember the prior 11 years of his life. His LTM was damaged but his STM was fine as he lost the ability to remember experiences a few years before his surgery but could recall childhood events.
L- This provides evidence for the idea that the compartments of the MSM work separately and independently from each other and one can still function even if other stores can’t.
What is another strength that supports the multi store model of memory?( research support)
P- A strength of the MSM is support from studies that show that STM and LTM are different.
E- For example, Baddeley (1966) found that we tend to mix up words that sound similar when we’re using our STMs. However we mix up words that have similar meaning when we use our LTMs. Further support comes from the studies of capacity and duration.
L- These studies clearly show that STM and LTM are separate and independent memory stores as claimed by the MSM.
What is a counterpoint to the research support for MSM?
P- In everyday life we form memories related to all sorts of useful things such as faces,names facts,places etc.
E- But many of the studies that support the MSM used none of these materials and instead used digits and letters such as Jacobs or words such as Baddeley and even consonant syllables with no meaning such as Peterson and Peterson.
L- This means that the MSM may not be a valid model of how memory works in our everyday lives where we have to remember more meaningful information.
What is a limitation of MSM?
P- One limitation of the MSM is evidence of more than one STM store.
E- A client called KF who had clinical memory disorder called amnesia. KF’s STM for digits was very poor when they were read out loud to him but his recall was much better when he read the digits to himself. Further studies of KF and others showed that there could even be another STM store for non verbal sounds eg noises.
L- This evidence suggests that MSM is wrong in claiming that there’s just one STM store processing different types of information( visual,auditory etc.)
What are the types of long term memory?
According to the MSM the LTM was too simple and fixed so Tulving (1985) suggested there were 3 stores in the LTM
1. Episodic memory
2. Semantic memory
3.Procedural memory
What is episodic memory?
How we recall events like a dairy eg what you had for dinner yesterday etc.
- time stamped as it stores info about how events relate to each other in time
- a single episode memory includes several elements eg place people objects and behaviors are INTERWOVEN
- have to make conscious effort to recall and happens quickly but still aware you’re searching
What is semantic memory?
shared knowledge of the world like a dictionary eg meaning of words
- NOT time stamped
-constantly being added to
-less personal more about facts we all share
- less vulnerable to distortion and forgetting than episodic memory