Peterson and Peterson - duration of STM

• Peterson & Peterson (1959)

  Researchers who investigated the duration of short-term memory
• Peterson & Peterson's study

  1. Conducted a laboratory experiment

  2. Sample of 24 psychology students

  3. Recall meaningless three-letter trigrams

  4. Prevent rehearsal by counting backwards

  5. Recall letters at different intervals (3, 6, 9, 12, 15 or 18 seconds)
• The longer the interval, the less accurate the recall
• At 3 seconds, around 80% of the trigrams were correctly recalled, whereas at 18 seconds only 10% were correctly recalled
• Peterson & Peterson's conclusion

  • Short-term memory has a limited duration of approximately 18 seconds
  • If unable to rehearse information, it will not be passed to long-term memory, providing further support for the multi-store model and the idea of discrete components