Memory
Multi-Store Model of Memory - Atkinson and
Shi rin (1968)
Sensory Register (SR)
‣ Automatic response to any sensory information by the sense organs
‣ All information passes through
Coding in the SR
‣ Stored in a raw, unprocessed form
‣ Separate sensory stores for di erent inputs
Iconic store: visual
Echoic store: auditory
Gustatory store: taste
Olfactory store: smell
Haptic store: tactile (touch)
Research on coding
‣ Crowder (1993) found the SR retains information in the iconic store for a few
milliseconds but 2-3 seconds in the echoic store
‣ Supports the idea that di erent sensory information is coded in di erent stores which
have di erent durations
Evaluation
‣ Face validity as after-images produced by moving a light shows good evidence for
sensory memories
Capacity of the SR
‣ Unlimited
‣ Information contains highly detailed and in an ever-changing format
Research on capacity
‣ 3x4 grids were ashed onto a screen for 1/20th of a second and participants were
asked to recall letters of 1 row
‣ Recall of letters was high suggesting all the information was there and the capacity of
the iconic store is very large
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,Memory
Evaluation
‣ Low mundane realism and external validity as it is an arti cial task which wouldn’t be
done every day
‣ You cant prove anything so inferences have to be made
Duration of the SR
‣ 250 milliseconds but di ers between di erent sensory stores
Research
‣ Walsh and Thompson (1978) said the iconic store has an average duration of 500
milliseconds which decreases as individuals get older
‣ Suggests duration is limited and dependant on age
Evaluation
‣ Biological explanation for duration due to brief duration of sensory memories as their
physical trace fades quickly
‣ Evolutionary theory suggests people only need to focus on perceptual information with
an immediate survival value
‣ Retaining non-useful information would stop this
Short-term Memory (STM)
‣ Temporarily stores information received from the SR
‣ Contains information you pay attention to
‣ Is an active memory system containing information currently being thought about
Coding in the STM
‣ Arrives in its raw form from the SR and is then encoded in an easier form
‣ Mainly coded acoustically
Visually: thinking of an image
Acoustically: repeatedly saying the word
Semantically: by using knowledge
Research of coding - Baddeley (1966)
Aim
To assess coding in the STM and LTM
Procedure
‣ 75 participants were presents with lists repeated 4 times
A. acoustically similar (sound the same)
B. acoustically dissimilar (sound di erent)
C. semantically similar (mean the same)
D. semantically dissimilar (di erent meanings)
‣ To test coding in the STM: participants were given a list with original words in the
wrong order and they had to rearrange them
‣ To test coding in the LTM: same procedure but 20 minutes later to ensure information
was in the LTM (during the break, participants did a task to prevent rehearsal)
Findings
STM
‣ Participants given list A performed the worst (10%) - confused similar-sounding words
‣ Recall for other lists was around 60-80%
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LTM
‣ Participants given list C performed the worst (55%) - confused similar-meaning words
‣ recall for other lists was around 70-85%
Conclusion
‣ There was acoustic confusion suggesting the STM is coded acoustically
‣ There was semantic confusion suggesting the LTM is coded semantically
Evaluation of the Study
Strengths Weaknesses
Face validity - if you had to remember a Lacks ecological validity - it isn’t
shopping list you would repeat the words representative
but if you remember a book you remember
the plot
High internal validity - lab experiment so it Some stimuli like faces or smell of food
can be replicated and there is a cause and would be di cult to code acoustically
e ect relationship
Capacity of the STM
‣ 7±2 items can be held
‣ Chunking increasing the capacity by grouping lots of information together to make it
easier to remember
Research
‣ Jacobs (1887) found that people could recall 7 digits in an immediate recall task but 9
items for letters
‣ There are less letters than numbers to remember so letters have probably been
rehearsed more individually than every number
‣ Simon (1974) said the e ectiveness of chunking varies with the material being recalled
and the amount of information within the chunks
‣ Daneman and Carpenter (1980) found capacity varied between 5 and 20 chunks
between those with advanced and poor reading comprehension
‣ Suggests practice a ects STM capacity
Evaluation
‣ Age and practice and also a ect STM capacity
Duration of the STM
‣ 18-30 seconds
‣ This can be extended by rehearsals information and if done for long enough, will
transfer the information into the LTM where it will become a more log-lasting feature
Research
‣ Peterson and Peterson (1959) got students to recall 3 letters after longer and longer
intervals
‣ 90% of trigrams were recalled correctly after 3 seconds, 5% after 18 seconds
‣ Suggests duration is between 20-30 seconds
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