1. Research support for the duration of STM
A01: Peterson and Peterson (1959), used nonsense trigrams. Pps were given an
interference task to stop them rehearsing the words and then asked to recall the
trigrams after differing time periods at 3 seconds intervals. After 3 seconds - 80%
recall, after 18 - 10%. Thus, STM has a very limited duration of about 18s when
rehearsal is prevented.
A03: low ecological validity. Artificial task that doesn't represent real. Trying to
memorise consonant syllables does not fully reflect most everyday activities when
memory is involved. However, we do sometimes try to remember phone numbers.
Therefore, even though the task is artificial, the study has some relevance to
everyday life.
2. Duration of LTM might be up to a lifetime.
A01: Bahrick (1975), 392 American ex-high school students between 17-74 years.
Free recall of the names of former classmates, photo recognition test. After 48 years,
70% accuracy for photos, free recall 30%.
A03: High external validity. However, only testing memory for faces we know, and so
may be representative of all types of memory. It is possible that memory for faces is
a distinct type of memory and recalled for longer than others. Humans are social
species, in terms of evolutionary survival, it would be highly adaptive.
3. Capacity of STM
A01: Jacobs (1887) used digit span test to assess capacity of STM. Found that the
average span for digits was 9.3 items and 7.3 for letters. Supported by Miller (1956)
5-9 items of larger chunks of information.
A03: However, individual differences. Jacobs found that digit span increased steadily
with age; 8 year olds could remember an average of 6.6 digits, whereas the mean for
19 year olds was 8.6 digits. Due to changes in brain capacity and development of
strategies such as chunking.
Therefore, the capacity of STM is not fixed and ind differences play a role.
4. STM and LTM are encoded differently.
A01: Baddeley (1966), when testing STM it was harder to recall words that are
acoustically similar (rat, hat, fat). When recall was tested after 20 min recall of words
with similar meaning were more difficult to recall than non-similar. Therefore, STM is
encoded acoustically and LTM semantically.
A03: However, some experiments shown that visual codes are also used on STM.
Brandimote et al found that pps used visual coding in STM if they were given a visual
task(pictures) and prevented from doing any verbal rehearsal in the retention
interval. Normally, we translate visual images into verbal codes in STM, but as verbal
rehearsal was prevented, pps used visual codes.
Therefore, STM may not be exclusively acoustic
A01: Peterson and Peterson (1959), used nonsense trigrams. Pps were given an
interference task to stop them rehearsing the words and then asked to recall the
trigrams after differing time periods at 3 seconds intervals. After 3 seconds - 80%
recall, after 18 - 10%. Thus, STM has a very limited duration of about 18s when
rehearsal is prevented.
A03: low ecological validity. Artificial task that doesn't represent real. Trying to
memorise consonant syllables does not fully reflect most everyday activities when
memory is involved. However, we do sometimes try to remember phone numbers.
Therefore, even though the task is artificial, the study has some relevance to
everyday life.
2. Duration of LTM might be up to a lifetime.
A01: Bahrick (1975), 392 American ex-high school students between 17-74 years.
Free recall of the names of former classmates, photo recognition test. After 48 years,
70% accuracy for photos, free recall 30%.
A03: High external validity. However, only testing memory for faces we know, and so
may be representative of all types of memory. It is possible that memory for faces is
a distinct type of memory and recalled for longer than others. Humans are social
species, in terms of evolutionary survival, it would be highly adaptive.
3. Capacity of STM
A01: Jacobs (1887) used digit span test to assess capacity of STM. Found that the
average span for digits was 9.3 items and 7.3 for letters. Supported by Miller (1956)
5-9 items of larger chunks of information.
A03: However, individual differences. Jacobs found that digit span increased steadily
with age; 8 year olds could remember an average of 6.6 digits, whereas the mean for
19 year olds was 8.6 digits. Due to changes in brain capacity and development of
strategies such as chunking.
Therefore, the capacity of STM is not fixed and ind differences play a role.
4. STM and LTM are encoded differently.
A01: Baddeley (1966), when testing STM it was harder to recall words that are
acoustically similar (rat, hat, fat). When recall was tested after 20 min recall of words
with similar meaning were more difficult to recall than non-similar. Therefore, STM is
encoded acoustically and LTM semantically.
A03: However, some experiments shown that visual codes are also used on STM.
Brandimote et al found that pps used visual coding in STM if they were given a visual
task(pictures) and prevented from doing any verbal rehearsal in the retention
interval. Normally, we translate visual images into verbal codes in STM, but as verbal
rehearsal was prevented, pps used visual codes.
Therefore, STM may not be exclusively acoustic
