STM vs LTM: Capacity

Question 1

Define capacity

Answer 1

-The amount of information that can be held in a memory store.

Question 2

Research on capacity- Digit span

Answer 2

STM capacity- Jacobs
- Developed a technique to measure digit span.
- Researcher gives, for example, 4 digits and then the ppt has to recall them in the correct order out loud.
- If this is correct the researcher reads out 5 digits and so on until the ppts cannot recall the order correctly.
- This determines an individuals digit span.

Question 3

Research on capacity- Digit span (findings)

Answer 3

• Jacobs found that the mean span for digits across all ppts was 9.3 items. The mean span for letters was 7.3 items.

Question 4

Define chunking

Answer 4

• Grouping sets of digits or letters together into units or chunks.

Question 5

Span of memory- Research

Answer 5

Miller:
- Made observations of everyday practice.
- E.g. he noted that things come in sevens= 7 notes on musical scale, 7 days of the week, 7 deadly sins etc.
- This suggests that the span of STM is about 7 items (+ or - 2) (7+/-2).

Question 6

Chunking- Research

Answer 6

• Miller also noted that people can recall 5 words as well as they can recall 5 letters (they do this by chunking).

Question 7

Evaluating research into capacity of memory: Digit Span

Answer 7

Limitation= conducted a long time ago.
- Early psychological research lacked adequate control.
- E.g. some ppts may have been distracted while they were being tested so did not perform as they liked.
- This may mean the results might not be valid because there were confounding variables that were not controlled.
- This decreases the internal validity.

Question 8

Evaluate research into capacity of memory: Span of memory

Answer 8

Limitation= he may have overestimated the capacity of STM.
- E.g. Cowan reviewed other research and concluded that the capacity of STM was only about 4 items.
- This suggests that the lower end of Millers estimate (5 items), was more appropriate than 7 items.