coding capacity and duartion

coding capacity and duartion

1. research on coding

   • memory system stores information in different formats depending on the memory stsore
   • the process of converting information from one store to another
   • baddley 1966 gave a list of words to 4 groups to learn
     • gave another 1 of 4 lists
       • acoustically similar
       • acoustically disimilar
       • semantically similar
       • semantically disimilar
   • then asked to recall original
     • recall that was straight after was worst with the acoustically similar words
     • recall 2 minutes after was worse with semantically similar words
     • suggests information is coded semantically in LTM and acoustically in STM
   • evaluation
     • artificial stimuli
       • because the word lists had no personal meaning to the participants and so was artificial we have to be cautious when generalising to different kinds of memory tasks such as processing more meaningful information as we may use semantic coding for some stm tasks. this then suggests the finding have limited application

2. research on capacity

   • digit span
     • jacobs 1887 gave 4 digits to a participant who was asked to recall it correctly
       • added a digit until it was recalled incorrectly
       • mean span = 9.3 items/digits
       • mean span = 7.3 letters
     • span of memory and chunking
       • miller 1956 made observations that things come in 7s so suggest the span -s 7+- 2
       • also noted people can recall 5 words / letters into chunks through chunking by grouping sets of digits into chunks
   • how much information can be held in the STM at one time
   • evaluation
     • not so many chunks
       • it is suggested that the capacity is overestimated as cowan 2011 reviewed other research and concluded the capacity was 4 chunks this hits at the lower end on millers estimate is more realistic

3. research on duration

   • (STM) Peterson 1958 gave a group of undergraduates a trigram to remember than a 3 digit number to count backwards from to prevent rehearsal
     • evaluation
       • meaningless stimuli
         • they had to memorise consonant syllables which don't reflect real-life memory so lacks external validity. however, we do sometimes have to remember meaningless things such as phone numbers
   • found the longer the individual was counting for the less correct the answers
     • suggests STM ahs a short duration unless the information is repeated
   • balrick et al 1975 studied 392 particpants from ohio 17-74
     • the recall was tested using a yearbook
       • photo recognition
         • 50 photos some were from their year
       • free recall
         • recall all the names from their class
       • tested within 15 years = 90/60% accurate
         • tested within 48 years= 70/30% accurate
     • evaluation
       • higher external validty
         • real life memories are shown but there is a confounding variable that isn't controlled as the participants could have looked at their yearbook photos recently or memorised them