Memory - Coding, capacity and duration of memory Flashcards
Capacity memory is defined as …
the amount of information that can be held in a memory store
What is the suggestion about the capacity of the Sensory Register
There is no limit of capacity for SR / its unlimited
Capacity - Short Term Memory key researcher & technique
Jacobs (1887) and his technique was called Digit Span Technique
Capacity - STM procedure
Participant A reading out letters/numbers and participant B recalling them. As they went on, the numbers/digits increased until one digit / number was incorrectly called
Capacity - STM findings
He found that the mean for span of digits was 9.3
he found that the mean span for letters was 7.3
Capacity - STM strengths
standardised method
if they included 7 or w we would not know if we were measuring the amount of syllables they could remember
Capacity - STM weakness
explicit what he was testing > nervousness
extraneous variables
Capacity - STM Additional Researcher
Miller
Capacity - STM additional research observation
He observed that things come in 7, for example seven deadly sins, 7 wonders of the world, seven colours in the rainbow, seven days a week
Capacity - STM additional proposition
He proposed the idea of chunking which is remembering things in chunks like phone numbers
chunking
remembering things in chunks like phone numbers
Capacity - LTM key researcher
there is no key researcher !!
what is the suggestion about the capacity of LTM
There is no capacity for LTM / it is unlimited
Duration of memory is defined as …
how long information can be held in memory store
Duration - SR key researcher
there is none !!
Duration - if attention is not paid to information in the SR, then it only lasts for …
1/2 a second
Duration - STM key researchers
Peterson & Peterson
Duration - STM example of a nonsense trigram
YGC
Duration - STM procedure
1) Students took part in 8 trials
2) Each trial the student was given a trigram to remember (such as YGC) and a 3 digit number
3) the students had to count back from the 3 digit number to prevent maintenance rehearsal
4) each trial, they would stop at different amounts of time – 3,6,9,12,15,18
Duration - STM findings
Decays over a short period of time, short term memory has the ability to last long. Absolute maximum capacity is 18-30 for short term memory without rehearsal
Duration - STM - Estimate what percentage of correct responses at each retention interval there was
3 seconds – 80
6 seconds – 55
9 seconds – 30
12 seconds – 23
15 seconds – 14
18 seconds - 12
Duration - what main conclusion can be taken about the duration of STM?
Absolute maximum capacity is 18 - 30 for short term memory without rehearsal
Duration LTM key researcher
Bahrick et al (1975)
Duration LTM how many partcipants
392
Duration LTM what stimuli did they use?
Old year books
Duration LTM what two things did they test
photo recognition task
free recall task
Duration LTM what were the findings
photo recognition – 90% accurate if they graduated in the last 15 years, 70% accuracy if they graduated within 48yrs
Free recall task – 60% accuracy if graduated in the last 15 years, 30% accuracy if they graduated within 48 yrs
Coding of memory is defined as …
The format in which information is stored in various memory stores
The coding of the sensory register is …
modality specific
Coding - SR 5 sense
eyes - iconic
ears - echoic
touch - tactile
taste - gustatory
nose - olfactory
coding - STM and LTM key researcher
Baddley (1966)
Acoustic meaning
words that sound similar
semantic meaning
words that have similar meaning
Coding - what experimental design was used?
Coding - what were the groups?
Group 1 - acoustically similar = cat, cab, can
Group 2 - acoustically dissimilar = pit, few, cow
Group 3 - semantically similar = large, big, colossal
Group 4 - semantically dissimilar = good, huge, hot
Coding - findings
When asked to recall word list immediately…
they struggled to record the correct order of the acoustically similar word > acoustic confusion
focusing too much on how the words sound and getting confused by this
When asked to do a task which took 20 minutes before recalling …
they struggled to recall semantically similar words > semantic confusion
Therefore, STM is encoded acoustically and the LTM semantically.
Coding - when asked to recall word list immediately …
they struggled to record the correct order of the acoustically similar word > acoustic confusion
focusing too much on how the words sound and getting confused by this
Coding - when asked to do a task which took 20 minutes before recalling ..
When asked to do a task which took 20 minutes before recalling …
they struggled to recall semantically similar words > semantic confusion
Coding - conclusion
Therefore, STM is encoded acoustically and the LTM semantically.
Coding, Sensory Register
no key researcher
modality specific
> iconic, echoic etc
Capacity, Sensory Register
no limit / unlimited
Duration, Sensory Register
less than 1/2 a second
Coding, STM
Baddley
acoustically
Capacity, STM
Jacobs - digit span technique = 9.3 numbers and 7.3 letters
Miller = 7 +- 2 chunks
Duration, STM
Peterson & Peterson
18 - 30 seconds
Coding, LTM
Baddley
semantically
Capacity, LTM
no limit / unlimited
Duration, LTM
Bahrick
more than 47 years
AO1
- Coding is the format in which information is stored. The sensory register is modality-specific. Baddeley researched coding of STM and LTM using 4 conditions, which tested memory of acoustically or semantically similar or dissimilar words. Immediate recall was worse with acoustically similar words, meaning that the STM encodes acoustically. Recall after 20 minutes was worse with semantically similar words, showing LTM is encoded semantically.
- Capacity is the amount of information that can be held in memory store. Through a digit span study, Jacobs found that on average people could remember 9.3 digits and 7.3 letters. Miller advanced these findings by noticing that thing often come in 7s and concluded that it 7+-2 chunks of information may be a better representation of STM capacity. The capacity of the LTM is unlimited.
- Duration is the length of time that information is held in memory stores. The sensory register has a duration of less than half a second, unless paid attention to. Peterson and Peterson found a limited duration of 18 seconds in the STM, by testing how well participants could remember a nonsense-trigram when counting backwards to prevent maintenance rehearsal. Bahrick found that after 48 years, people are still able to remember names and faces of classmates, tested from a yearbook, suggesting an unlimited duration of the LTM.
AO3
- A weakness of research into the capacity of STM is that it might be outdated.
- For example, Jacob’s study was conducted in 1887, over 100 years ago at a time where psychology often lacked adequate control.
- This is a weakness because 137 years ago, psychologists would not have been aware of the need for such tight manipulation of the environment and variables, meaning that participants may have experienced confounding variables such as distraction which may have affected how much they could remember.
- Method
- However, it could be argued that Jacob’s findings have been confirmed by other, better controlled studies when it has been replicated, showing the internal validity of the results for STM
- Despite this, the research lacks temporal validity as the researchers may not find the same conclusions about capacity of STM if they were to do in 2024 where we have control.
- Therefore, the MSM may not be relevant nowadays as an explanation of memory and therefore lacks temporal validity.
- A weakness of research into the duration of STM is that it uses meaningless stimuli.
- For example, Peterson and Peterson used nonsense trigrams such as YCG as their memory stimuli and provided random 3 digit numbers such as 789 to count back from.
- This is a weakness because using such meaningless stimuli is a weakness of the research because it limits how confident we can be when generalizing the findings about how long our memory lasts, outside of the experimental setting. In everyday life, we form memories related to all sorts of useful and relevant things, such as names, faces, facts and birthdays and not a random groups of letters
- Additionally, meaningless stimuli creates a lack of mundane realism as it cannot be generalised to real-life natural settings
- However, some could argue that meaningless stimuli was important to use in this situation, because if participants were given trigrams that meant something to them, it undoubtedly would have gone to their LTM quicker due to the personal meaning, and therefore the study would not be truly testing what it intended to.
- Despite this, the research has low external validity as there has not been research to show how long the STM is when the stimuli is more relevant information to us.
- This consequently decreases our trust in the multi-store model to be able to accurately describe human’s memory processes.
- A weakness of research into coding is that they may not have investigated what they intended to.
- For example, the longest gap that Baddeley left between learning and recall was 20 minutes.
- This is a weakness because this methodological choice can be questioned, as 20 minutes may not represent what we mean by LTM. When people refer to LTM, they tend to also think about years in the future, which this research may not represent.
- Method
- However, it may be argued that 20 minutes is good level of control for someone to be able to rehearse something.
- Despite this, to truly test coding of LTM they should have measured further into the future, in order to be more robust with the findings.
- Therefore, the MSM lacks internal validity we cannot be sure it explains what it wanted to.
- A strength of research into the duration of LTM is that it used meaningful stimuli.
- For example, Bahrick used real life events such as school photos within the recall tasks
- This is a strength because using meaningful and person stimuli is a strength of the research because means we can be more confident when generalizing the findings about how long our LTM lasts, outside of the experimental setting.
- Method
- However, it can be argued that using year book photos can be considered as an extraneous variable as it is easier for the person to remember as with Bahricks study he doesn’t know how many times that person has looked at the year book over time which means he can’t control for the extraneous variable that people could have read the yearbook, reducing its reliability.
- Despite this, the research is useful as we can be more assured that the conclusions represent human memory.
- This means that we can claim the Multi-Store Model has high levels of external validity as it is likely to explain our memory processes in everyday situations.
