1_SHORT TERM MEMORY

1_SHORT TERM MEMORY

1. Short term memory can differ in 3 ways

   • DURATION
     • refers to how long a memory lasts before it is no longer available.
     • Duration of STM is approx. 20 seconds
     • DECAY = when you lose a memory (losing the information)
   • CAPACITY
     • Refers to how much information stores can hold
     • STM = 5-9 items
       • After this, any new info displaces the other info held in STM
   • CODING
     • Refers to the way in which information is transformed in order to be stored in the memory
       • Info in STM is coded acoustically or visually,

2. REHEARSAL = practising/learning information so that it gets transferred into LTM, therefore improving STM. e.g. writing a story or repeating it

3. PETERSON & PETERSON (1959)

   • Aimed to test short term memory - specifically the duration
   • They read out 3 letters without meaning and then gave them a number and asked them to count down in 3s from that number
     • They had different periods of time to do this for e.g. 3-18 seconds.
       • After this time had passed, they had to recall the letters they were given at the start.
   • They found that most people were able to recall the letters at the shorter lengths of time e.g. 6-8 secs.
     • After this, the percentages of people getting it right fell and at 18 secs it fell significantly
       • PROVES THE THEORY THAT STM LASTS APPROX. 20 SECONDS.
   • At 3 seconds there was as high as 90% accuracy and at 18 there was as little as 2%

4. JOSEPH JACOBS - DIGIT SPAN

   • Aimed to measure capacity of STM
   • The researcher gives 4 digits and then the participant has to recall them in the correct order out loud.
     • If they are correct the researcher will read out 5 digits and so on until the participant cannot recall correctly.
       • This determines their digit span.
   • He found that the 'mean' number for digits was a 9.3. The mean span for letters was 7.3

5. George miller (1956)

   • Made observations of every day practice & noted that things came in sevens .
     • 7 Notes on a music scale, 7 days in a week 7 deadly sins ect
     • Suggests that the span of the STM is around 7 items.
     • He also noticed that people can recall 5 words as well as they can recall 5 letters
       • They do this by 'chunking' - grouping sets of objects together in units or chunks
         • Postcode system was developed by Badldeley due to his research into chunking

6. ALAN BADDELEY - RESEARCH ON CODING

   • Gave different lists of words from 4 groups to remember
     • E.g. acoustically similar/dissimilar, Semantically similar/dissimilar
     • Participants were shown the original words and asked to recall them in the correct order.
       • When they did it immediately after hearing it, they did worse with the acoustically similar words
         • When they did it after 20 mins, they did worse with the semantically similar words.
           • Suggests info is coded semantically in LTM