M: Short- and long-term memory Flashcards
(36 cards)
Your memory for events in the present or immediate past (e.g. trying to remember an order of drinks at a bar) is referred to as what?
Short- term memory
Your memory for events that have happened in the more distant past (e.g. remembering this distinction between STM & LTM in an exam) is referred to as what?
Long-term memory
STM and LTM are often distinguished in terms of what?
Their capacity, duration and coding.
What does capacity concern?
What is the capacity of STM and LTM?
- Concerns how much data can be held in a memory store.
- STM is a limited capacity store whereas LTM has a potentially infinite capacity.
How can the capacity of STM be assessed?
Using digit span.
The capacity of STM
What did Joseph Jacobs (1887) do in one of his earliest studies in psychology?
What did he find?
- He used the technique of using the digit span to assess STM capacity.
- He found that the average span for digits was 9.3 items and 7.3 for letters.
The capacity of STM
What did Joseph Jacobs suggest was the reason for why it was easier to recall digits?
He suggested that it may be because there are only 9 digits whereas there are 26 letters.
What did George Miller (1956) write and what did he conclude?
- He wrote a memorable article called The magic number seven plus or minus two, in which he reviewed psychological research.
- He concluded that the span of immediate memory is about 7 items- sometimes a bit more and sometimes a bit less.
What did George Miller discover?
Think in terms of what he noted about people: what could they recall?
- He noted that people can recall 7 dots flashed onto a screen but not anymore.
- The same is true if you are asked to recall musical notes, letters and even words.
- He also found that people can recall 5 words as well as they can recall 5 letters- we chunk things together then can remember more!
What are the evaluation/ discussion points for capacity?
- The capacity of STM may be even more limited.
- The size of the chunk matters.
- Individual differences.
A criticism of the research investigating STM is that Miller’s original findings have not been replicated. Explain this.
- Cowan (2001) reviewed a variety of studies on the capacity of STM and concluded that STM is likely to be limited to about 4 chunks.
- Research on the capacity of STM for visual information (rather than verbal stimuli) also found that 4 items was about the limit (e.g. Vogel et al., 2001).
- This means that the lower end of Miller’s range is more appropriate (i.e. 7-2 which is 5).
- This suggests that STM may not be as extensive as was thought.
Evaluation/ discussion- the size of the chunks matters?
- It seems that the size of the chunk affects how many chunks you can remember.
- Simon (1974) found that people had a shorter memory span for larger chunks, such as 8-word phrases, than smaller chunks, such as one-syllable words.
- This continues to support the view that STM has a limited capacity and refines our understanding.
Evaluation discussion, capacity, Individual differences?
- The capacity of STM is not the same for everyone.
- Jacobs also found that recall (digit span) increased steadily with age; eight year olds could remember an average of 6.6 digits whereas the mean for 19 year olds was 8.6 digits.
- This age increase might be due to changes in brain capacity, and/or to the development of strategies such as chunking.
- This suggests that the capacity of STM is not fixed and individual differences may play a role.
What did Lloyd Peterson and Margaret Peterson (1959) study and what did they do?
- Studied the duration of STM, using 24 students.
- Each participant was tested over 8 trials.
- On each trial a participant was given a consonant syllable and a three-digit number.
- They were asked to recall the consonant syllable after a retention interval of 3,6,9,12, 15 or 18 seconds.
- During the retenention interval they had to count backwards from their three-digit number.
What were the findings in Lloyd Peterson and Margaret Petersons 1959 study?
What did the findings suggest?
- Participants on average were 90% correct over 3 seconds, 20% correct after 9 seconds and only 2% correct after 18 seconds.
- It suggests that STM has a very short duration- less than 18 seconds- as long as verbal rehearsal is prevented.
The duration of LTM
What did Harry Bahrick et al. (1975) do?
- He tested 400 people of various ages (17-74) on their memory of classmates.
- A photo recognition test consisted of 50 photos, some from the participant’s high-school yearbook.
- In a free-recall test participants were asked to list the names they could remember of those in their graduating class.
The duration of LTM
What were the findings in Harry Bahricks test?
- Participants who were tested within 15 years of graduation were about 90% accurate in identifying faces.
- After 48 years, this declined to about 70% for photo recognition.
- Free recall was about 60% accurate after 15 years, dropping to 30% after 48 years.
Evaluation/ discussion -DURATION
Discuss how testing STM was artificial…
P: A criticism of research investigating STM is that it is artificial.
E: Trying to memorise consonant syllables does not truly reflect most everyday memory activities where what we are trying to remember is meaningful.
E: However, we do sometimes try to remember fairly meaningless things, such as groups of numbers (phone numbers) or letters (post codes).
L: This means that, although the task was artificial, the study does have some relevance to everyday life.
Duration- Evaluation/ discussion
Discuss- STM may be due to displacement.
P: A criticism of the Peterson’s study is that it did not actually measure what it set out to measure.
E: In the Peterson’s study participants were counting the numbers in their STM- this may displace or ‘overwrite’ the syllables to be remembered.
E: Reitman (1974) used auditory tones instead of numbers so that displacement wouldn’t occur (sounds don’t interfere with verbal rehearsal) and found that the duration of STM was longer.
L: This suggests that forgetting in Peterson’s study was due to displacement rather than decay.
How is information ‘written’ in our memory?
It is described as a ‘code’ in which it is held in the form of sounds (acoustic), images (visual) or meaning (semantic).
Acoustic and semantic coding
What are the following words in terms of acoustic and semantic coding?
cat, cab, can ,cad, cap, mad, max, mat, man, map.
They are acoustically similar but semantically different.
What are the following words in terms of acoustic and semantic coding?
Great, large, big, huge, broad, long, tall, fat, wide, high
They are semantically similar but acoustically different.
Acoustic and semantic coding
What did Alan Baddeley (1966a and 1966b) use and what did they test?
What were the findings and what did it suggest?
- Used words lists to test the effects of acoustic and semantic similarity on STM and LTM.
- He found that participants had difficulty remembering acoustically similar words in STM but not in LTM, whereas semantically similar words posed little problem for STMs but led to muddled LTMs.
- This suggests that STM is largely encoded acoustically whereas LTM is largely encoded semantically.
Coding, Evaluation/ discussion- STM may not be exclusively acoustic.
P: Some experiments have shown that visual codes are also used in STM.
E: Brandimote et al. (1992) found that participants used visual coding in STM if they were given a visual task (pictures) and prevented from doing any verbal rehearsal in the retention interval ( they had to say ‘la la la’) before performing a visual recall task. Normally we ‘translate’ visual images into verbal codes in STM but, as verbal rehearsal was prevented, participants used visual codes.
E: Other research has shown that STM sometimes uses a semantic code (Wickens et al., 1976).
L: This suggests that STM is not exclusively acoustic.
