CODING, CAPACITY AND DURATION OF MEMORY

• Coding (format information is stared in) - BADDELEY (1966) 


  Procedure =

  Acoustically similar words (E.G cat, cab, can) or dissimilar (E.G pit, few, cow).

  Sematically similar (E.G great, large, big) or dissimilar (E.G good, huge, hot). 

  Findings = 

  Immediate recall worse with acoustically similar words, Stm is acoustic.

  Recall after 20 mins worse with semantically similar words, LTM is semantic.
• Capacity (quantity of info the store can hold) - JACOBS (1887) Testing digit span


  Procedure =

  Researcher reads 4 digits and increases until the participant cannot recall the order correctly. Final number = digit span. 

  Findings =

  On average, partiocipants could repeat 9.3 numbers and 7.3 letters in the correct order immediately after they were presented. 
• Capacity 


  MILLER (1956) MAGIC NUMBER 7 +/- 2:

  Procedure =

  Miller observed everyday practice, noted that things come in 7 - notes of musical scale, days of the week, deadly sins etc.

  Findings =

  The span of STM is about 7 items (plus or minus 2) but is increased by chunkinmg - grouping sets of digits/letters into meaningful units. 
• Duration (how long info stays) STM - PETERSON AND PETERSON (1959) consonant syllables


  Procedure = 

  24 students were given a consonant syllable (E.G YCG) to recall and a 3 digit number to count backwards from. The retention interval was varied: 3,6,9,12,15 or 18 seconds. 

  Findings = 

  After 3 seconds - avg recall was about 80%. After 18 seconds it was about 3%. STM duration without rehearsal is up to 18 seconds. 
• Duration LTM - BAHRICK ET AL. (1975) Yearbook photos


  Procedure =

  Participants were 392 Americans aged between 17 and 74.

  1. Recognition test - 50 photos from high school yearbooks. 
  2. Free recall test - participants listed names of their graduating class. 

  Findings =

  Recognition test - 90% accurate after 15 years, 70% after 48 years.

  Free recall test - 60% recall after 15 years, 30% after 48 years.