, Coding, capacity and duration of memory
Research on coding
The format in which information is stored in the various memory stores.
Allen baddely conducted an experiment
Group 1. Acoustically similar
Group 2. Acoustically dissimilar
Group 3. Semantically similar
Group 4. Semantically dissimilar
They tend to do worse in acoustically similar words. If they were asked to
recall rewards after 20 minutes, they did worse with semantically similar
words, this proves that information is coded semantically.
Artificial stimuli. The words had no meaning to the participants, so hard to
generalise.
Research on capacity
Digit span
Joseph jacobs gave words to the participants and asked to recall and
eventually they’ll increase number of words. He found that the mean span
for numbers was 9.3 and for letters 7.3.
Lacks validity because of confounding variables, however there are studies
that back these results, supporting its validity.
Span of memory and chunking
George miller found that things usually come in 7s, the capacity is 7+-2.
Chunking is grouping sets of digits or letters into units or chunks.
Cowan found that the capacity of short term memory was only four chunks,
so 5 Items is more appropriate than 7.
Research on duration
Duration of STM
Peterson and Peterson tested 24 undergraduate students, each student
took part in 8 trials. On each trial the student, they were given a trigram and
a 3 digit number and told to count backwards, to avoid any mental
rehearsal. On each test they were told to stop at different seconds. This is
called retention interval, STM has short duration unless repeated.
Lacks mundane realism because the words are meaningless and random.
Duration of LTM
Bahrick studied 392 participants from America aged between 17-74. Told to
recall names and photo recognition of their high school years. Those who
tested within 15 years, 90% accurate in PR. After 48 years 70%, after 15
years 60% and after 48 years 30%
High external validity because the photos were meaningful.
Research on coding
The format in which information is stored in the various memory stores.
Allen baddely conducted an experiment
Group 1. Acoustically similar
Group 2. Acoustically dissimilar
Group 3. Semantically similar
Group 4. Semantically dissimilar
They tend to do worse in acoustically similar words. If they were asked to
recall rewards after 20 minutes, they did worse with semantically similar
words, this proves that information is coded semantically.
Artificial stimuli. The words had no meaning to the participants, so hard to
generalise.
Research on capacity
Digit span
Joseph jacobs gave words to the participants and asked to recall and
eventually they’ll increase number of words. He found that the mean span
for numbers was 9.3 and for letters 7.3.
Lacks validity because of confounding variables, however there are studies
that back these results, supporting its validity.
Span of memory and chunking
George miller found that things usually come in 7s, the capacity is 7+-2.
Chunking is grouping sets of digits or letters into units or chunks.
Cowan found that the capacity of short term memory was only four chunks,
so 5 Items is more appropriate than 7.
Research on duration
Duration of STM
Peterson and Peterson tested 24 undergraduate students, each student
took part in 8 trials. On each trial the student, they were given a trigram and
a 3 digit number and told to count backwards, to avoid any mental
rehearsal. On each test they were told to stop at different seconds. This is
called retention interval, STM has short duration unless repeated.
Lacks mundane realism because the words are meaningless and random.
Duration of LTM
Bahrick studied 392 participants from America aged between 17-74. Told to
recall names and photo recognition of their high school years. Those who
tested within 15 years, 90% accurate in PR. After 48 years 70%, after 15
years 60% and after 48 years 30%
High external validity because the photos were meaningful.
