AQA A-level Psychology notes
& exam questions: Memory
Sensory memory
Coding: Modality specific. Information is held in the same sense that
it is registered – sight, hearing, touch, smell and taste.
Capacity: Large. This was theorised from a study by Sperling. He used
a tachistoscope and presented a 12 symbol grid for 1/20th of a second
on a screen. Participants could recall 4 symbols, but saw more than
they had time to report. This demonstrates the capacity of SM is
large. However although evidence suggests that the capacity of SM is
very large, it isn’t well studied as the images last so briefly and
generally at a high level.
Duration: 0.25 – 2 seconds.
Short-term memory
Coding: Acoustic. Causes confusion when material sounds similar.
- Conrad showed students letters one at a time to study coding in
STM. He found acoustically similar letters are harder to recall,
concluding STM coding is acoustic.
Capacity: 7 +/- 2 items (5 to 9), as theorised by Miller. However he
felt it could be expanded if we chunked items together to reduce the
number of items overall. However he might have overestimated this
as Cowan found the capacity of STM was only around 4 chunks.
Duration: 15-30 seconds if maintenance rehearsal isn’t used.
,Peterson & Peterson (1959) (IMPORTANT STUDY)
Their aim was to investigate the duration of STM. 24 psychology
students were shown trigrams, followed by a distractor task of
counting back in 3s from a number for 3-18 seconds to prevent
rehearsal. They then tried to recall the words. After 3 seconds, 80%
of the words were recalled, while only 10% at 18 seconds. They
concluded that STM has a limited duration of 18-30 seconds if
rehearsal is prevented.
Evaluation:
- A limitation of the study is the stimulus material is artificial.
They used consonant-syllables to memorise in a controlled,
artificial environment, so it doesn’t reflect real-life activities and
lacks ecological validity.
- The study supports the explanation that the memory trace
disappears after a short duration if not rehearsed. However,
info. in STM could also be displaced as it has a limited capacity
and any new info. pushes out what is currently in STM. In the
study participants counted back in 3s which could have led to
displacement, so the study lacks ecological validity.
Long-term memory:
Coding: Semantic.
- Baddeley presented 10 short words one at a time. Some lists
were semantically similar, others not. Participants were tested
immediately and after 20 minutes. After 20 minutes, they did
poorly on the semantically similar words. This suggests that
coding in LTM is semantic. However he used artificial stimuli so
the results may have a limited application.
Duration: Up to a lifetime.
- Bahrick tested participants 48 years after their graduation and
they were 70% accurate in photo recognition after being given a
, recognition test asking to match names of former classmates to
50 photos in a yearbook. They were 392 Americans aged 17-74.
Real, meaningful memories were studied, so this research has
high ecological validity, however confounding variables are not
controlled as they may have looked at their yearbooks over the
years.
Capacity: Potentially unlimited.
The multi-store model
The multi-store model was created by Atkinson and Shiffrin in 1968.
(credit for the diagram goes to psychology wizard)
In SM, info. is lost through decay if not paid attention to. In STM, it is
lost through displacement if not rehearsed due to its limited capacity.
In LTM it is lost through decay.
Evidence for the MSM
A clinical case study of HM, a man who underwent surgery for
epilepsy, can be used as an example for evidence. The surgery
damaged his LTM, so he could not transfer new memories from STM
to LTM. This suggests there are at least 2 separate distinct stores, one
can be damaged and the other one remain intact.
& exam questions: Memory
Sensory memory
Coding: Modality specific. Information is held in the same sense that
it is registered – sight, hearing, touch, smell and taste.
Capacity: Large. This was theorised from a study by Sperling. He used
a tachistoscope and presented a 12 symbol grid for 1/20th of a second
on a screen. Participants could recall 4 symbols, but saw more than
they had time to report. This demonstrates the capacity of SM is
large. However although evidence suggests that the capacity of SM is
very large, it isn’t well studied as the images last so briefly and
generally at a high level.
Duration: 0.25 – 2 seconds.
Short-term memory
Coding: Acoustic. Causes confusion when material sounds similar.
- Conrad showed students letters one at a time to study coding in
STM. He found acoustically similar letters are harder to recall,
concluding STM coding is acoustic.
Capacity: 7 +/- 2 items (5 to 9), as theorised by Miller. However he
felt it could be expanded if we chunked items together to reduce the
number of items overall. However he might have overestimated this
as Cowan found the capacity of STM was only around 4 chunks.
Duration: 15-30 seconds if maintenance rehearsal isn’t used.
,Peterson & Peterson (1959) (IMPORTANT STUDY)
Their aim was to investigate the duration of STM. 24 psychology
students were shown trigrams, followed by a distractor task of
counting back in 3s from a number for 3-18 seconds to prevent
rehearsal. They then tried to recall the words. After 3 seconds, 80%
of the words were recalled, while only 10% at 18 seconds. They
concluded that STM has a limited duration of 18-30 seconds if
rehearsal is prevented.
Evaluation:
- A limitation of the study is the stimulus material is artificial.
They used consonant-syllables to memorise in a controlled,
artificial environment, so it doesn’t reflect real-life activities and
lacks ecological validity.
- The study supports the explanation that the memory trace
disappears after a short duration if not rehearsed. However,
info. in STM could also be displaced as it has a limited capacity
and any new info. pushes out what is currently in STM. In the
study participants counted back in 3s which could have led to
displacement, so the study lacks ecological validity.
Long-term memory:
Coding: Semantic.
- Baddeley presented 10 short words one at a time. Some lists
were semantically similar, others not. Participants were tested
immediately and after 20 minutes. After 20 minutes, they did
poorly on the semantically similar words. This suggests that
coding in LTM is semantic. However he used artificial stimuli so
the results may have a limited application.
Duration: Up to a lifetime.
- Bahrick tested participants 48 years after their graduation and
they were 70% accurate in photo recognition after being given a
, recognition test asking to match names of former classmates to
50 photos in a yearbook. They were 392 Americans aged 17-74.
Real, meaningful memories were studied, so this research has
high ecological validity, however confounding variables are not
controlled as they may have looked at their yearbooks over the
years.
Capacity: Potentially unlimited.
The multi-store model
The multi-store model was created by Atkinson and Shiffrin in 1968.
(credit for the diagram goes to psychology wizard)
In SM, info. is lost through decay if not paid attention to. In STM, it is
lost through displacement if not rehearsed due to its limited capacity.
In LTM it is lost through decay.
Evidence for the MSM
A clinical case study of HM, a man who underwent surgery for
epilepsy, can be used as an example for evidence. The surgery
damaged his LTM, so he could not transfer new memories from STM
to LTM. This suggests there are at least 2 separate distinct stores, one
can be damaged and the other one remain intact.
