Encoding, Duration, Capacity

Encoding, Duration, Capacity

1. DURATION

   • STM
     • 20 Seconds
       • Peterson + Peterson (1959) With 24 Uni ptpt's, said a 3 letter word followed by a 3 digit number, they had to remember this whilst counting backwards from a said number if 3's or 4's so they could not rehearse in their head. They found ptpt's remembered 90% when only 3 second counting back interval and 2% with 18 second interval.Suggests when rehersal prevented, STM last 20 seconds tops.
   • LTM
     • Potentially Unlimited
       • Shepard (1967) Showed Ptpt's 612 memorable pictures, one hour later recall almost perfect, four months later 50% were recognized.

2. CAPACITY

   • LTM
     • Potentially Unlimited
   • STM
     • 7+/-2
       • George Miller (1956) Reviewed Psychological research and concluded the span of the immidiatte memory is 7. He also found people can recall 5 words as well as 5 digits (chunking) Chunking allows us to remember more.
       • Joseph Jacobs ( 1887) Digit-span technique. Showed ptpt's one digit, and then adding one each time. He found digits remembered on average was 9.3, but for letters it was 7.3. This may be due o the fact there are only 9 number whilst there are 26 letter possibilities.

3. ENCODING

   • STM + LTM
     • Acoustically
     • Semantically
     • Baddeley (1966) Gave ptpt's list of words which were acoustically similar dissimilar and words which were semantically similar or dissimilar. He found ptpt's had difficulty remembering acoustically similar words in STM but not in LTM, whereas semanticallysimilar words posed little problem for STM recall but not in LTM and visa versa for semantically similar words.