coding, capacity and duration of memory Flashcards
what is the capacity for sensory register
unlimited
what is coding for sensory register
modality specific
what is duration for sensory register
less than half a second
what is capacity for short term memory
7 +/- 2
research for capacity of short term memory
MILLER(1956)
Observed things that come in 7s , eg 7 days of the week, 7 deadly sins , 7 notes in the musical scale
We are predisposed to remembering the quantity and ‘chunking’ (remembering in small chunks) method can help us recall information
7 +/- 2 items
JACOBS (1887) [digits span technique]
Researcher reads out four digits and the participant recalls these out loud in the correct order, if this is correct then the researcher moves onto 5 digits and so on until the participant cant recall the order correctly –> indicates the individuals digit span
Digits (9.3) letters (7.3)
how does STM code
acoustically
research for coding for STM + LTM
BADDELEY (1966)
Gave different lists of words to four groups of participants to remember
Group 1 – acoustically similar –> cat,cab,can
Group 2 – acoustically dissimilar–> pit,few,cow
Group 3 – semantically similar –> colossal, large, big
Group 4 – semantically dissimilar –> good, huge, hot
When asked to recall words immediately (STM) –> participants did worse semantically similar words
When asked to recall the list after some time (LTM) –> do worse on acoustically similar words
Information is coded from acoustically in STM and semantically in LTM
coding for LTM
semantically
capacity for LTM
unlimited
duration for STM
less than 18s
research for duration of STM
PETERSON AND PETERSON (1959)
Students took part in 8 trials
On each trial they were given a nonsense trigram and a three digit number
Student had to count back from the three-digit number to prevent maintenance rehearsal
On each trial, they would stop at different amounts of time (3,6,9,12,15,18)
3-80%
6-56%
9-33%
12-23%
15-13%
18-11%
18-30 seconds without maintenance rehearsal
duration for LTM
at least 48 years
research for duration for LTM
BAHRICK ET AL (1975)
392 American participants aged 17-74
High school year book photos as stimulus
Recall was tested in two different ways 1. photo recognition task consisting 50 photos 2. free recall task , recall names of their graduating class
Photo recognition task : 90% accuracy if graduated within 15 years; 70% accuracy if graduated within 48 years
Free recall task : 60% accuracy if graduated within 15 years ;30% accuracy if graduated within 48 years
strength of coding capacity duration studies
P - High external validity
E- Investigated meaningful memories (people’s names and faces)
E/L we can be more confident when generalising the findings about how long our LTM lasts, outside of the experimental setting
weakness of coding capacity duration studies
P- meaningless stimuli
E- peterson and Peterson Used nonsense trigrams such as YCG as stimuli and provided random 3 digit number to count back on
A- Weakness as it limits how confident we can be when generalising he 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
C- Therefore, basing the conclusions of how long our STM lasts on laboratory study with tightly controlled and manipulated stimuli, might not accurately reflect the length in real life. It may be that the length of STM is different when it is more relevant information to us.
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P- may not have tested out what it intended to
E- The longest gap that Baddeley left between learning and recall was 20 minutes.
A- 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.
C- Therefore, this research creates cautiousness about our confidence in the claim that LTM is always encoded semantically, as to test coding of LTM more robustly, they should have measured further into the future.
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P- extremely outdated
E- Jacob’s study was conducted in 1887, over 100 years ago at a time where psychology often lacked adequate control.
A- 137 years ago, psychologists would not have been aware of the need for such tight manipulation of the environment and variables
C- meaning that participants may have experienced confounding variables such as distraction which may have affected how much they could remember
E- Therefore, this is a weakness as if the same research was conducted into the capacity of STM in 2023, different results may be found.
