Coding, capacity & duration of memory Flashcards
What is coding?
The format in which information is stored in memory stores
What was Baddeley’s research on coding procedure?
- group 1 given acoustically similar words to remember (cat cab etc)
- group 2 given acoustically dissimilar words (pit, few, cow)
- group 3 given semantically similar words (great, large big)
- group 4 given semantically dissimilar words (good, huge, hot)
What was Baddeley’s research findings and conclusions?
- when they had to recall words immediately participants tended to do worse with acoustically similar words
- when they had to recall after 20 minutes participants did worse on semantically similar words
- suggest The STM is coded acoustically while the LTM is coded semantically
How did Jacobs find out how much information the STM can hold at one time?
By measuring participants digit span
What is capacity?
The amount of information that can held in a memory store
What was the procedure for Jacobs digit span test?
- The researcher read out four digits and participants had to recall this out loud in the correct order
- digits increased until participants could no longer remember
What was the mean span for digits and the mean for letters across all participants in Jacobs study?
- 9.3 items for digits
- 7.3 items for letters
What did Miller observe & note from his observations?
- observed everyday practices , & noticed that things come in sevens, 7 notes on musical scale, 7 days of the week, 7 deadly sins
What did Miller think that span of the STM was and how do people recall easily?
- 7 items plus or minus two
- we recall easily by chunking information- grouping sets of digits or letters into units or chunks
What is duration?
The length of time information can be held in memory
Who measured duration in the STM?
Peterson & Peterson
What was Peterson & Peterson procedure?
- tested 24 students in 8 trials
- each trial the student was given a consonant syllable to remember
- also given a 3 digit number
- student counted backwards from number until told to stop out loud (prevent mental rehearsal of syllable)
- told to stop after varying times
What did Peterson & Peterson find?
- after 3 secs average recall of syllable was 80%
- after 18 secs it was about 3%
What does Petersen & Petersen suggest about the duration of STM?
- 18 seconds unless information is repeated over and over
Who measured duration in the LTM?
Bahrick et al
What was Bharick’s research procedure?
- 392 p’s age 17-74
- high school yearbooks were obtained from participants or directly from schools
- recall was tested in 2 ways:
1) photo recognition test consisting of 50 photos
2) free-recall test where participants recalled all the names of their graduating class
What were Bharick’s findings & conclusions?
- after 48 years= recall was 70% for photo recognition
- after 48 years= recall was 30% for free recall
- This shows that the STM may last up to a lifetime for some material
What is a strength of Baddeley’s study?
- It identified a clear difference between two memory stores
- the idea that the STM is mainly coded acoustically & LTM mainly semantic has stood the test of time
- important step in our understanding of the memory system (led to MSM)
What is a limitation of Baddeley’s study?
- uses quite artificial stimuli rather than meaningful material
- e.g. world lists had no personal meaning to P’s
- findings do not tell us much about coding in different kinds of memory tasks, especially in everyday life
- limited application
What is a strength of Jacobs’ study?
- has been replicated
- old study so lacked adequate controls e.g. some participants digit spans might have been underestimated because they were distracted during testing (CV)
- however, better controlled studies have confirmed Jacobs findings (Bopp & Verhaeghen)
- valid test of digit span
What is a limitation of Miller’s research?
- may have overestimated STM capacity
- Cowan reviewed other research and concluded that the capacity of the STM is only about 4+-1 chunks
- suggest the lower end of Miller’s estimate is more appropriate than 7 items
What is limitation of Peterson & Peterson’s study?
- stimulus material was artificial
- recalling consonant syllables does not reflect most everyday memory activities where what we are trying to remember is meaningful
- lacks external validity
What is a strength of Bahrick’s stduy?
- has high external validity
- researcher investigated meaningful memories (names & faces)
- When studies were conducted with meaningless pictures to be remembered recall rates were lower (Shepard)
- Barracks findings reflect a more ‘real’ estimate of duration in the LTM
