Coding Capacity Duration

• Duration- Bahrik- high school year book photos (1975), 


  found that 15 years post grad were 90% correct, pps who graduated almost 50 years ago were still correct 70% of the time, supports LTM theory of potentially lasting forever
• Baddeley- pps found it harder to remember acoustically similar words straight after encoding, but harder to with semantically similar a long time after encoding, supports STM and LTM claims


  conclusion- LTM must rely on semantic coding, STM must rely on acoustic coding,
• peterson and peterson trigrams- duration- 3 letter trigrams for pps to remember, then were asked to count back from 3 digit number to prevent trigram rehearsal, pps were stopped at 3 seconds to 6 and so on till they could not remember the trigram- the trigrams could only hold in memory for 18-30 seconds- DURATION OF STM

  Drawback- trigrams not reflective of real life instances, lacking ecological validity, trigrams have no external meaning to pps
• miller- capacity- 7+/-2 items average recall for pps using digit span technique- 7 words can be as easily recalled as 7 letters as we chunk items into meaningful units to aid memory

  research in 1956 lacked vigorous control, results may not be valid due to confounding variables
• DRAWBACK OF MILLER- Cowan's research in 2001 suggests short term memory is only around 4 chunks, miller may have overestimated, suggests the lower end of miller's estimate (5 compared to 7) may be more appropriate, therefore this study reduces the validity of miller's research with a different outcome than him 


  research against miller