Coding, Capacity and Duration

Coding
1. Baddeley gave different lists of words to four groups of participants to remember
  1. Group 1: Acoustically similar
    1. STM found hard to recall in order
      1. Suggests we code acoustically in STM
  2. Group 2: Acoustically dissimilar
  3. Group 3: Semantically similar
    1. LTM found hard to recall after 20 minutes
      1. Suggests we code semantically in LTM
  4. Group 4: Semantically dissimilar
  5. Has separate memory stores which is a strength and helps with the understanding of MSM
  6. A limitation is that it used artifiial stimuli rather than meaningful material
Capacity
1. Joseph Jacobs measured digit span in 1887
  1. He would read out a digit order containing 4 digits then add one each time they got the sequence correct
    1. Mean span for digits was 9.3 items and the mean span for letters was 7.3
  2. Although it is very old, it weas replicated and his findings were confirmed by Bopp and Verhaeghen in 2005
2. George Miller (1956) realised that most things come in sevens (7 days, 7 notes on music scale, 7 deadly sins)
  1. Miller's Magic Number = 7-+2
    1. Supports Jacobs initial findings
  2. Also noted we could remember 5 words as easy as 5 letters and we do this by chunking (grouping sets of digits/letters together)
  3. He may have overestimated the STM capacity as Cowan (2001) reviewed other research and concluded that the capacity is around 4+-1
Duration
1. Peterson and Peterson tested 24 students in 8 trials
  1. Student given consonant syllable to remember (such LRW)
  2. Also given 3-digit number and the student counted back in threes until told to stop (299, 296, 293 etc)
  3. Stopped at 3,6,9,12,15,18 seconds to ask for consonant syllable (retention interval)
  4. After 3 seconds, average recall = 80% and after 18 seconds average recall = 3%
    1. Peterson and Peterson decided that the STM was about 18 seconds unless we repeat the info multiple times (verbal rehearsal)
  5. The stimulus material was artificial as it was nonsensical syllables but we do try remember meaningless material such as phone numbers but it does not reflect day-to-day behaviour which means the study lacked external validity
2. Harry Bahrick et al (1975) studied 392 American participants between ages 17 and 74
  1. Tested in photo-recognition
    1. 90% after 15 years
    2. 70% after 48 years
  2. Tested in free recall
    1. 60% in 15 after 15 years
    2. 30% after 48 years
  3. This shows that the LTM may last up to a lifetime for some material
  4. It has high external validity as researchers have investigated meaningful memories and when studies on LTM were conducted with meaningless pictures the recall rates were lower which suggests Bahrick's findings reflect a more 'real' estimate of the duration of LTM

Next up

Coding, Capacity and Duration

Description

Resource summary

Similar

	Created by Jackson Maleary about 4 years ago