Short and Long Term Memory

Short and Long Term Memory

1. Capacity

   • Jacobs
     • Digit span is 9.3 for digits, 7.3 for letters
   • Miller
     • People remember about 7 items and 7 chunks

2. Evaluation of Capacity

   • Cowan- 4 chunks is probably the limit. Same for visual information
   • Simon- larger chunks means fewer items are recalled
   • Jacobs- 19-year-olds have longer digit span than 8-year-olds

3. Duration

   • Peterson and Peterson
     • Used consonant syllables, prevented verbal rehearsal. STM lasted 18 seconds
   • Bahrick et al
     • After 48 years, participants were 70% accurate in face recognition of classmates and 30% for names

4. Evaluation of Duration

   • Consonant syllables are not meaningful but some memory activites do involve such stimuli (e.g. initials)
   • Reitman- auditory tones to avoid displacement led to a longer duration of STM
   • Nairne et al- duration for STM is 96 seconds

5. Coding

   • Baddeley
     • Difficulty remembering acoustically similar words in STM but not in LTM, it is the reverse for semantically similar words

6. Evaluation of Coding

   • In Baddeley's study, LTM was tested by waiting 20 minutes but it could be argued this isn't really LTM
   • Brandimote et al- STM is visually coded if verbal rehearsal is prevented
   • Wickens et al- STM sometimes uses a semantic code
   • Frost- found evidence for visual coding in LTM