4.1.2 SHORT TERM MEMORY Flashcards
what’s the short term memory?
- known as a limited capacity store
- holds a small amount of information for short period of time
- holding device before memory is forgotten / lost
OR moved into the long term memory
what is the capacity of short term memory?
who found this out and when?
Miller (1956)
METHOD
- asked participants to recall information, adding an extra bit as he moved on
- started participants with two or three words to recall
- gradually built it up until they made an error
FINDINGS
- found that the capacity of STM could be considerably increased by combining/organising separate ‘bits’ of information ( known as chunking)
- most participants struggled with between 5-9 words
- this is known as ‘Miller’s Magic 7’
how can we evaluate research into capacity and short term memory?
Jacobs (1887)
METHOD
- similar experiment using digits with 443 female students
- called this a digit span experiment using numbers instead of words
FINDINGS
- results were similar to Miller’s
- 7.3 was the average recall
how does this evaluate Miller’s study?
- shows it is reliable as it’s easy to copy and the results are more often than not the same
- as it’s a lab study, extraneous variables would have been controlled
- it could be argued to lack ecological validity as the task bears little resemblance to real life
what is the duration of short term memory?
- short term memory is only a temporary device so duration is limited
- is a very short amount of time
- around 18-30 seconds
what is the method of evidence for the duration of short term memory?
Peterson and Peterson (1959)
METHOD
- gave participants a non-sensical three-letter trigram to learn eg) CGR or BHT
- these were presented visually, one at a time
- participants had to recall the trigram in the correct order after a delay of either 3s, 6s, 9s, 12s, 15s or 18s
-during the delay they were asked to complete a distraction task: usually counting backwards from 300 in 3’s
- this was to prevent them from rehearsing during the delay
what are the findings for the delay of the evidence for STM duration?
- graph of the correctly recalled trigrams over time was plotted and was shown to be a decay curve
- this demonstrates that over time the memory seems to decay
- after 30s recall in STM would be zero
- therefore, P+P stated that the duration of STM was 18-30s
what is the evaluation of duration in the STM?
- Peterson and Peterson conducted a well-controlled study
- many extraneous variables would have been removed or controlled
- validity of the study is challenged
- previous trigrams (maybe similar to the one being recalled) could have interfered with the memory and this is why the participant made the mistakes
what is encoding in the short term memory?
- encoding is how the information is processed from the senses into the memory itself
- this is how it will be stored and recalled
- encoding is always in the form of a modality/one of the senses
- STM encodes acoustically or using sound
what is the evidence for acoustic encoding in short-term memory?
who and when?
Baddely (1966)
METHOD
- he gave participants four lists of words to learn
acoustically similar, acoustically dissimilar, semantically
similar, semantically dissimilar
- the words were all presented visually on a screen as part of a slideshow
- free recall was not allowed
- he asked for immediate recall
FINDINGS
- he found the acoustically similar words had the worst recall
- there was no difference for the semantically similar and dissimilar words
- he concluded that STM relied on acoustic encoding to process information
how can we evaluate the research into encoding in short term memory?
- lab experiment so is highly controlled
- extraneous variables taken care of
- lacks ecological validity as the tasks don’t relate to real life
- the words had little to no meaning for participants and so they were harder to recall
- information we have to recall in reality often has meaning and significance so it makes recall easier
