Coding, capacity and duration Flashcards
what is coding?
The process of converting information between different forms
Who did the key study of coding?
Alan Baddeley (1966)
What 4 groups of words were tested?
- acoustically similar
- acoustically dissimilar
- semantically similar
- semantically dissimilar
what words did participants do worse with after immediate recall?
acoustically similar
What words did participants do worse with after 20 minutes?
semantically similar
How is our STM coded?
acoustically
How is our LTM coded?
semantically
what are the strengths of Baddeley’s (1966) procedure?
- identified a clear difference between two stores
- idea of acoustic and semantic coding has stood the test of time
- important step into understanding of MSM
what are the weaknesses of Baddeley’s (1966) procedure?
- artificial stimuli - no meaning to participants
- lack of mundane realism
- limited application
What is capacity?
How much information our brain can hold at once
Who did the key research on capacity of STM?
Joseph Jacobs (1887)
what was Jacobs (1887) procedure?
researcher reads out 4 digits which participant immediatley recalls in correct order, researcher increases number of digits until recalled incorrectly.
what was the mean digit span?
9.3 items
what was the mean letter span?
7.3 items
What are the strengths of Jacob’s (1887) procedure?
- been replicated
- confimed by other, newer studies
What are the limitations of Jacob’s (1887) procedure?
- old
- lacked adequate control
Who made observations on capacity of STM?
George Miller (1956)
what did Miller (1956) observe?
Things come in sevens (days of the week, deadly sins, notes on music scale).
What did Miller (1956) conclude capacity of STM was?
7 (+/- 2) items
What is chunking?
Grouping larger information into groups of smaller information.
What are the limitations of Miller’s (1956) procedure?
- just an observation
-over-estimation
-Cowan (2001) suggested STM is only 4 (+/-1)
What is duration?
The length of time information can be held in our brains before we forget.
who did they key study of duration of STM
Peterson and Peterson (1959)
What was Peterson and Peterson’s (1959) procedure?
tested students (24), gave them consonant syllables to remember, given 3 digit number to count down from for a given amount of time. After counting down they would have to recall the consonant syllables.
Why did the participants have to count backwards?
To prevent mental rehearsal
What were the periods of time participants had to count down from?
3, 6, 9, 12, 15, 18
What was the average recall after 3 seconds?
80%
What was the average recall after 18 seconds?
3%
What was the conclusion on the duration of STM?
18 seconds
What were the limitaions of Peterson and Peterson’s (1959) study?
- material was artificial
- doesn’t reflect everyday memory
- lacked external validity
Who did the key study on duration of LTM?
Harry Bahrick (1975)
what was Bahrick’s (1975) procedure?
324 (17-74) participants given yearbooks (their own and others) to be tested on.
what were the two recall tests?
photo recognition
free recall, participants recalled their graduating class
what was the recall of participants who graduated 15 years ago?
photo recognition- 90%
free recall - 60%
what was the recall of participants who graduated 48 years ago?
photo recognition- 70%
free recall - 30%
Whats the duration of LTM?
up to a lifetime
What are the strengths of Bahrick’s (1975) study?
- high external validity
- used meaningful material
