Short term memory Flashcards
What is meant by the term Short term memory?
A system for storing information for brief period of time.
How did Atkinson and Shriffrin (1968) see STM as?
A temporary storage depot for incoming informatin
How did Baddeley (1986) see STM as?
Preferred to used the term working memory to show its dynamic and flexible aspects
What is the capacity?
Limited capacity
What does it mean by limited capacity
Only holds small amounts of information before it’s forgotten
What study shows the capacity of STM
Serial digit span studies
Explain what serial digit span studies are?
PP’s are given incresingly long sequences of digits in which they have to recall back in serial order.
When do participants reach their digit span capacity?
When they fail on 50% if the trials
Which two researchers used digit span studies?
Baddeley (1975)
Jacobs (1887)
Explain Jacob’s study of immediate digit span?
Used to investigate the STM capacity.
Procedure:
He read aloud a list of either letters or numbers then gradually increased the length until it was impossible for them to recall back in serial order
Findings:
STM capacity for digits was 9 and letters was 7
STM increased with age- 8 y/o recalled 7 digits but 19 y/o recalled 9 digits.
Conclusions:
STM capacity is between 5 and 9 and age does affect it bcos people increase recall strategies with ages and practice.
Also numbers are easier to recall than letters bcos there are fewer of them (9) than letters (25)
What are the strengths and weaknesses of Jacobs (1887) study?
Strengths:
Replicated research
- replicated by Miller (1956)
-Atkinson and Shiffrin (1968)- argued STM store had a small number of ‘slots’ where information could e help and that the limited capacity was bcos of small number of slots.
Weaknesses:
There are other factors such as age and practice which influence STM.
Who suggested that most people have a digit span of seven plus or two?
Miller (1956)
What did Miller believe?
Our immediate memory span is determined by the number if chunks of information we can hold instead of the individual letters or numbers
What did simon (1974) find about STM capacity?
The spam measured in chunks depends in the amount of information in the chunk.
He experimented with serial recall
He found that people have shorter span for longer chunks than smaller chunks
What were Glanzer and Razels (1974) findings on STM capacity?
Used recency effect as a measure of STM capacity.
Findings:
Recency effect was 2.2 items when the stimulus material had single unrelated words but increased to 1.5 sentences when unfamiliar sentences were given and to 2.2 proverbs when familiar proverbs were used.
Who is the researcher that studied word length effect of immediate memory span to see if people could recall more short words than long words in a serial recall test?
Baddeley et al (1975)
Explain Baddeley et al (1975) research study?
Procedure:
-Measured the reading speed of the participants then were given sets if five words.
-The words were either one syllable words or a set of polysyllable words
- Then they were asked to recall the words back in serial order
Findings:
-PPs recalled more short words than long words
-They could recall as many words as they could articulate in about 2 secs
-Strong positive correlation between memory span and reading speed
Conclusion:
Immediate memory span shows the number of items of any length that could be articulated in about 2 seconds
What are the evaluative points (strengths and weaknesses) of Baddeley et al (1975) study?
Weaknesses:
Might just be bcos short words are easier to remember than long words bcos they are familiar to us
Miller hadn’t been able to account for findings of research which showed that immediate memory span depends on nature of stimulus ( i.e the kind of words and the nature in which they are spoken)
What are the factors that affect STM capacity?
- Influence of LTM
- Reading aloud
- Pronunciation time
- Rhythmic grouping
- Individual differences
Explain the influence of LTM
A problem with using immediate digit span as measure of STM capacity is it’s difficult to exclude the influence of LTM.
In terms of influence of LTM what did Cowan (2000) believe?
Miller may have overestimated the number of chunks held in STM
The performance on span tasks is usually affected by rehearsal to LTM but doesn’t show STM capacity .
Estimated that STM capacity is 4 chunks when factors are controlled.
In terms of influence of LTM what did Bower and Winzenz (1969) find?
Digit strings that are repeated witan series of immediate memory spans trails became easier for PPs to recall
W
What did Bower and Winzenz (1969) findings suggest?
The strings have been gradually rehearsed and stored in the LTM which helps increase STM capacity
Explain reading aloud
Digit span increases if PPs read the digits aloud instead of reading them sub vocally