Memory Flashcards
define short term memory
The limited capacity memory story
- coding is mainly acousting
- capacity is 7 +-2 items
- duration is about 18 seconds
Define long term memory
The permanent memory store
- coding is mainly semantic
- unlimited capacity
- unlimited duration
Define coding
The format in which information is stored in the various memory stores
Define capacity
The amount of information that can be held in a memory store
Define duration
The length of time information can be held in memory
What research has been done into coding
Baddeley
- gave lists of words to four different groups of pps
- 1: acoustically similar
- 2: acoustically dissimilar
- 3: semantically similar
- 4: semantically dissimilar
- pps were shown the original words and asked to recall them in the correct order
- STM: worse at recalling acoustically similar words
- LTM: worse at recalling semantically similar words
What does semantic mean
Have similar meaning
What does acoustic mean
Similar sounding
What are examples of capacity
- digit span
- span of memory and chunking
What is the digit span research into capacity
Jacobs
- researcher reads out 4 digits
- pps recalls them out loud in the correct order
- the researcher adds 1 more digit until the pps can no longer recall them
- this was the individuals digit span
- the mean span of digits was 9.3
- mean span of letters was 7.3
What is the research into span of memory and chunking
Miller
- noticed things come in groups of 7s
- 7 days, 7 deadly sins, 7 notes
- Miller thought that the capacity of STM is about 7 +-2 items
- people can really 5 words as easily as 5 letters
- this is done by chunking
What is chunking
Grouping sets of digits or letters into units or chunking
What was the research done into duration
- duration of STM
- duration of LTM
What research was done into the duration of STM
Peterson + Peterson
- tester 24 in 8 trials
- in each trial the student was given a constant syllable
- also given a 3 digit number
- student then counted backwards from a number until told to stop
- counting backwards prevented mental rehearsal
- told to stop after varying periods of time
- recall worsened with more time between hearing and recall
- 3 seconds = 80% recall
- 18 seconds = 3% recall
What research was done into duration of LTM
- Bahrick
- studied 392 American participants between 17-74
- high school year books were obtained
- recall was tested in various ways
- 1: photo recognition test consisting of 50 photos
- 2: free recall
- within 15 years = 90% accuracy
- after 48 years = 70% accuracy
- free recall was less accurate
- 15 years = 60% accuracy
- 48 years = 30%
Evaluation points for research on coding
- separate memory stores
- artificial stimuli
PEEL for separate memory stores = coding
- strength
- Baddeley’s study identifies a clear difference between two memory stores
- later research showed that there are some exception to his findings
- STM being acoustically coded and LTM being semantically coded has remained constant
- led to the multi-store model
PEEL for artificial stimuli - research on coding
- limitation
- used artificial stimuli rather than meaningful material
- word lists had no personal meaning
- findings might not tell us much about coding in different kinds of memory tasks
- meaningful information may use semantic coding
- limited application
Evaluation for research on capacity
- a valid study
- not so many chunks
PEEL for a valid study - research on capacity
- strength
- study has been replicated
- old psychology research often lacked adequate controls
- some pps digit spans might have been underestimated
- distracted during testing
- Jacobs findings have been confirmed y others
- valid test of digit span in STM
PEEL for not so many chunks - research on capacity
- limitation
- Miller’s research may have overestimated STM capacity
- Cowan reviewed other research
- concluded that STM capacity is only about 4 +-1 chunks
- the lower end of Miller’s estimate is more appropriate
Evaluation points for research on duration
- meaningless stimuli in STM study
- high external validity
PEEL for meaningless stimuli in STM study - research on duration
- limitation
- stimulus material was artificial for Peterson + Peterson
- not completely irrelevant
- we do sometimes try to remember fairly meaningless material (phone numbers)
- recalling constant syllables doesn’t reflect most everyday memory activities
- lacked external validity
PEEL for high external validity - research on duration
- strength
- Bahrick’s study has high external validity
- the researchers investigated meaningful meteorites
- when the study was conducted with meaningless pictures recall rates were lower
- findings reflect a more real estimate of he duration of STM