capacity of memory Flashcards
what are the three stages of memory?
encoding - storage - retrieval.
what is the capacity of memory in the STM and LTM?
STM:
7+-2 pieces of information.
LTM:
potentially unlimited.
define capacity.
the amount of information that can be held in a memory store.
what is the name of the study by Jacobs (1887)?
the digit span test.
outline the research by Jacobs (1887).
researcher gave ptps a number of digits and the ptp had t recall them in order.
the researcher then increased the amount by one digit and the ptp had to recall them again and so on until the ptp could not recall them in the correct order.
this determines an individuals digit span.
what did Jacobs find in his research into capacity of STM?
found that the mean digit span for ptp was 9.3 items.
for letters it was slightly lower at 7.3 items.
evaluate Jacobs digit span test.
Jacobs research was done in the 1800s, when research may not have been well controlled, so results may have been affected by confounding variables.
however, his research was based on a systematic and replicable procedure, and the findings have been replicated by more well controlled studies since then, which suggests that Jacobs study was a valid and reliable test of digit span in the STM.
what was the name of the study by Miller (1956)?
Millers magic 7.
outline the research by Miller (1956).
Miller observed everyday practise and argued that most things come in 7s - seven notes on a musical scale, seven days of the week etc.
he reviewed other peoples experiments and concluded that on average we can recall 7 items (7+-2), with a range of between 5-9 items.
he also noted that people remember more as long as we break down info into 5-9 manageable chunks.
he believed that people can recall 5 words as easily as they can recall 5 numbers - we do this by chunking, grouping sets of digits or letters into chunks.
evaluate Millers Magic 7.
Millers theory of STM holding 5-9 items is based on and supported by Jacobs (1887).
However, his theory that people can remember as many chunks as letters or numbers has been disproved. Cowan (2001) reviewed a variety of studies and concluded that the capacity of the STM is likely to be limited to around 4 chunks.
This was demonstrated by research that showed people have a shorter span for larger chunks than smaller chunks like one syllable words - showing the size of the chunk does matter and limiting the validity of Millers theory.
