Coding, Capacity and duration Flashcards
Process of coding
The format in which information is stored in various memory stores
Who investigated Coding?
Alan Baddeley (1966a, 1966b)
Alan Baddeley’s study into coding
Gave four different lists of words to four groups of participants:
- G1 - acoustically similar words (cat, cab, can)
-G2 - acoustically dissimilar words (pit, few, cow)
-G3 - semantically similar words (great, large, big)
-G4 - semantically dissimilar (good, huge, hot)
Participants showed words and asked to recall them immediately in the correct order (from short term memory)
Then asked to recall them after 20 minutes (from long term memory).
A mixture of 72 men and women used from Cambridge university, volunteered
Baddeley’s results
From short term memory, did worse with acoustically similar words, suggesting short term memory codes acoustically. As the STM pays not attention to what the words mean, but gets confused as they sound similar
From long term memory, did worse on with semantically similar words, suggesting long term memory is coded semantically
Baddeley - strengths
Strengths:
- Identified clear difference between stores
-Later research showed there are some exceptions to findings but the idea that STM codes semantically and LTM acoustically has remained
-Baddeley’s findings were important in development of multi-store model
Baddeley limitations
Limitations:
-Experiment used artificial stimuli rather than meaningful material, no personal meaning. May not tell about coding in different tasks in everyday life. When processing meaningful information, people may use semantic coding even for STM tasks
-Suggests investigation has limited application
Capacity of memory
The amount of information that can be held in a memory store
Research on capacity
Joseph Jacobs (1887) - digit span
Joseph Jacobs (1887) - procedure
-Researcher read out list of numbers for participants to recall in order
-If order was correct, list of numbers increases from 4 digits + until the participant is incorrect
-This indicates the individual’s digit span
Jospeh Jacobs’s - results
Found the mean span for digits across all participants was 9.3 items. Mean span for letters was 7.3
Jacob’s strengths
-Has been replicated various times
-Old studies can lack controls, e.g. (Digit span may have been underestimated as they were distracted when taking the test - confounding varibale)
-Jacob has been confirmed by controlled studies (Bopp and Vertaeghan 2005)
George Miller - 1956
Made observations of everyday items - lots come in groups of 7
Thought the span of STM was about 7, plus or minus 2
Claimed people can recall 5 words as easily as they can recall 5 letters. Do this by chunking
Miller’s limitation
Nelson Cowan (2001) - reviewed other research and found that STM is only about 4 (plus or minus 1) chunks
Said that the lower end (5 items) is more appropiate
Duration of STM
Margaret and Lloyd Peterson (1959) - tested 24 students in eight trials each
Given a 3 digit number, then told to count backwards until they were told too top (prevent mental rehearsal)
Told to stop after varying periods of time - 3, 6, 9, 12, 18 (retention interval)
Peterson and Peterson results
- After 3 seconds, average recall was about 80%
- After 18 seconds, average recall was about 3%
Peterson and Peterson’s findings suggested that STM duration may be about 18 seconds, unless we repeat the information over and over (verbal rehearsal)
