STM+LTM Flashcards
What is the Duration/Capacity/Encoding of the STM?
Duration- 18-30 second
Capacity- 7+/-2 items
Coding- Acoustic
What is the Duration/Capacity/coding of the LTM?
Duration- Lifetime duration
Capacity- Unlimited
Coding- Semantic
Who conducted research on the duration of the STM?
Peterson and Peterson gathered 24 undergraduates and they took part in 8 trials where they were given trigrams (YCG) and 3 digit numbers. Participants had to repeat the trigram after 3,6,9,12,15,18 seconds (retention intervals) and counted back from the number in the time in between to prevent rehearsal.
They found an 80% accuracy when recalling after 3 seconds and 10% accuracy after 18 seconds.
Who conducted research on the capacity of the STM?
Jacobs developed the digit span technique, where participants have to recall a sequence of numbers, where the number of numbers increase until they get it wrong, determining their digit span. Jacobs found that the mean span for numbers was 9.3 and for letters it was 7.3
Miller’s magic number seven, observation of everyday practices .
Who conducted research on the duration of the LTM?
Bahrick et al had 392 university graduates aged 17-74. He collected yearbooks and did a photo recognition test and a free recall test. Participants who graduated under 15 years later had a 90% accuracy rate and those graduated 48 years later had a 70% accuracy rate. However, during the free recall test, results dropped from 15 years- 60%, 48 years- 10%
Who conducted research on the coding of the STM and LTM?
Baddeley had 4 groups of participants and gave them words which were acoustically similar, acoustically dissimilar, semantically similar, semantically dissimilar. He tested straight after they heard the words to test the STM and 20 minutes after to test the LTM. He found that recall was worse in acoustically similar words when testing straight away and semantically similar words when testing afterwards.
What is chunking?
Miller said that the capacity of the STM can be increased by chunking which is when people convert a string of items into a larger chunk to remember more things.
