Research on capacity and duration of STM Flashcards
Who completed research on the capacity of STM?
Joseph Jacobs and George Miller
How did Joseph Jacobs measure the capacity of the STM?
Using digit span
What did Jacob’s find the mean span for digits was?
9.3
What are the 2 strengths of Jacobs’ study?
+ Has been replicated
+ The replication suggests that it is a valid test of digit span
What is the limitation of Jacobs’ study?
- As it is an old study, it may have not been done in a controlled way.
What did George Miller observe?
That many items come in groups of 7
What was Miller’s magic number?
7+/-2 which means that the capacity of the STM ranges between 5 and 9
What does ‘chunking’ mean?
Grouping sets of letters/digits together into units or ‘chunks’
What are the 2 limitations of Miller’s research?
- May have overestimated STM capacity
- Cowan reviewed other research, he said that STM capacity was 4+/-1
What is the strength of Miller’s research?
+ His lower estimation of 5 is closer to reality
Who conducted research on the duration of STM?
Peterson and Peterson
What was the Petersons’ procedure in their research?
- 24 students
- They were each given a consonant syllable to remember and a 3 digit number
- They had to count back until told to stop
- They were told to stop on each trial at varying lengths of time
In the Petersons’ research, why did they make the students count backwards?
To prevent mental rehearsal of the consonant syllable
After 3 seconds of counting backwards, what was the average recall? (P+P)
80%
After 18 seconds of counting backwards, what was the average recall? (P+P)
3%
