Memory Flashcards
What is coding?
The format in which information is stored in various memory stores
What is capacity?
The amount of information that can be held in a memory store at a given time
What is duration?
The length of time information can be held in a memory store
What is short term memory?
The limited capacity store. Coding is mainly acoustic, capacity is between 5 and 9 items, duration is between 18 and 30 seconds.
Capacity can be increased via chunking
What is long term memory?
The permanent memory store. Coding is mainly semantic, it has unlimited capacity and can store memories for up to a lifetime
Research into capacity, coding and duration of STM and LTM
Coding: Baddely (STM, LTM)
Capcity
STM - Jacobs and Miller
Duration:
STM - Peterson and Peterson
LTM - Bahrick
Baddeley aim
Research coding into stm and LTM
Baddeley procedure
- 4 sets of word lists - acoustically similar and dissimilar, semantically similar and dissimilar.
- participants recalled the order of word lists
- done immediately to assess stm and after 20 minutes for ltm
Baddeley findings
Participants given acoustically and Semantically similar words had the worst recall
They confused the similar sounding and meaning words
Baddeley conclusions
- lists that had poor recall showed that the words had become confused
- for immediate recall, acoustically sounding words weren’t remembered well, showing stm is acoustically coded as they remembered the others fine.
- for delayed recall, semantically sounding words were not remembered well, showing that LTM is semantically coded
Jacobs aim
Research capacity of stm
Jacobs procedure
Developed a technique to measure digit span - how many items an individual can remember, in sequence and repeat back in order
Jacobs findings and conclusions
Mean span for digits was 9.3 items and for letters it was 7.3
Concluded memory can hold 7-9 items
Miller aim
Research capacity of stm
Miller procedure
Observed things come in sevens e.g. days of the week.
Also used the digit span technique but ‘chunked’ items into groups e.g. sets of numbers
Miller findings
People could recall 5 words as well as they could recall 5 letters, via chunking
Miller conclusions
Used the term ‘the magical number seven’ to describe the capacity of stm
Peterson and Peterson aim
Research duration of stm
Peterson and Peterson procedure
- 24 students took part in 8 trials and were given a consonant syllable/trigram and asked to count backwards to prevent rehearsal
- on each trial, they were stopped after either 3,6,9,12,15 or 18 secs. This was the retention interval
Peterson and Peterson findings
STM lasts about 18 seconds after this, very few people correctly recall the consonant syllable
Peterson and Peterson conclusions
STM has a very short duration, unless it is rehearsed
Bahrick aim
Research duration of ltm
Bahrick procedure
Tested recall of people participants had gone to school with using photo recognition (50 yearbook photos) and free recall (recalled names)
Bahrick findings
90% accuracy for photo recognition for people who had graduated within 15 years ad 60% accuracy for free recall.
After 48 years photo recognition recall about 70% and 30% for free recall