The MSM research; Encoding, Duration and Capacity for STM and LTM

The MSM research; Encoding, Duration and Capacity for STM and LTM

1. Experiment on the Capacity of the STM

   • Aim - Whether the pronunciation time, rather than times recalled, determines STM capacity
   • Procedure - reading speed was measured. presented with 5 words on a screen. Two sets 1) one syllable words & 2) polysyllabic words.
     • asked to recall the 5 words in serial order. They recalled several lists of short and long words.
   • Findings - considerably more short than long words.able to recall as many as they could say in 2 secs. strong positive correlation with speed&memory

2. Natural Experiment on the duration of the LTM

   • Procedure - tracked down grads from an American high school over a 50 yr period.
     • over 400 were shown photographs and names, some from their yearbook. had to identify faces then names of classmates.
   • Findings - 90% correct in recognising faces and names 15 yrs after grad. correctly recalled 80%names & 70% faces 48 after grad.

3. Study on the Duration of the STM

   • Procedure - ppts were briefly shown a trigram (three letters such a CGW), immediately asked to count backwards in threes from a given number to stop thinking of the letters
     • after intervals of either 3,6,9,12,15 and 18 secs, they had to recall the trigram. repeated several times using different trigrams
   • Results - 80% could recall trigrams after 3 sec interval. after 18 secs fewer than 10 recalled the trigram. conc = stm is limited to 18 seconds if rehearsals prevented.

4. Study of encoding in STM and LTM.

   • Procedure - shown a list of 5 words, asked to immediately recall them in serial order. the list were either acoustic similar words, acoustic dissimilar words, semantically similar & semantically dissimilar. LTM was increased to 10 and recall after 20 seconds.
   • Findings for STM -similar sounds = more difficult to remember than dissimilar words. 10% accuracy on strings of similar words. 82% accuracy on dissimilar words.
     • Findings for LTM - 20 minutes after seeing the semantic similar had a negative effect. much better at recalling words with different meanings.