DURATION IN STM

DURATION IN STM

1. PETERSON & PETERSON (1959)

   • A: Wanted to find out how long data remains in STM when rehearsal is prevented
     • P: PP's were shown a constant trigram, e.g GBX or KJG. PP's then asked to count backwards in 3's from a specific number to prevent rehearsal (interference task). After interval of 3, 6, 9 , 12, 15 seconds, pp's were asked to recall the original trigram
       • F: The longer the recall interval in seconds, the less trigrams accurately recalled
         • STRENGTH:
           • It allows us to see the cause & effect in the experiment. It was carried out in controlled conditions & use of repeated measures design minimised the impact of individual differences. (High internal validity)
         • PROBLEMS:
           • It is possible that forgetting is caused by displacement (i.e. trigrams pushed out by capacity limitations being exceeded because of the counting task) rather than decay (fading over time). This means the internal validity of the study can be challenged
           • Constant trigrams are artificial things to remember. This means the task lacks mundane realism & so it is difficult to generalise the findings to real life situations.

2. FACTORS AFFECTING DURATION IN STM

   • MAINTENANCE REHEARSAL
     • When we try to remember a phone number, we continuously repeat it in our head in order for us to remember it- this keeps it in STM. Research has shown that if we do an interference task we are preventing rehearsal so the data disappears. This means rehearsal is an important factor in the duration of STM as without rehearsal, duration is very brief.
   • DELIBERATE INTENTION TO RECALL
     • If people don't make a conscious effort to retain info, it will disappear. Sebrechts found if people were briefly shown 3 common nouns, followed only 4 secs later by an unexpected serial recall test, correct recall was only 1%. This shows duration in STM is very brief unless a conscious effort to retain info is made.

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