Coding, Capacity and Duration of Memory

Question 1

Describe research on coding:

Answer 1

• Baddeley (1966) gave different lists of words to 4 different groups of participants to remember:
  
  • Group 1 (acoustically similar) words that sound the same
  • Group 2 (acoustically dissimilar)
  • Group 3 (semantically similar) words with similar meanings
  • Group 4 (semantically dissimilar)

Question 2

Describe the results of Baddeley’s (1966) research into coding:

Answer 2

• Participants were shown the original words and were asked to recall them in the correct order
• When this was done immediately afterwards (STM) they tended to do worse with acoustically similar words.
• When they did this after 20 mins (LTM) they did worse with semantically similar words
• This suggests that’s information is coded acoustically in the STM and semantically in the LTM

Question 3

What’s a strength and limitation of Baddeley’s research into coding?

Answer 3

• Strength that it identifies clear difference between memory stores that stood the test of time and is still used in the multi-store model
• Limitation that it was an artificial stimuli that had no personal meaning to the participants so has limited application to real life

Question 4

Describe research into capacity (digit span):

Answer 4

• Jacobs read out 4 digits then asked the participant to recall them out loud in the correct order
• If correctly recalled then another digit is added until they can’t go on to indicate their digit span
• Mean span for digits was 9.3 items and mean span for letters was 7.3 items

Question 5

Describe research into capacity (chunking):

Answer 5

• Miller (1956) made observations of everyday practice and noted that things come in sevens
• STM is about 7 items plus or minus 2 but also noted that people can recall 5 words as easy as they can recall 5 letters
• This is due to chunking sets of digits or letters

Question 6

What’s a strength and limitation Jacobs’ and Miller’s research into capacity?

Answer 6

• Strength that Jacoba’ has been replicated by Bopp (2005) and can be replicated if conditions are controlled - reliable due to research support
• Limitation that Miller’s may have overestimated STM capacity as Cowan (2001) concluded that’s its only 4 plus or minus 1 chunks - lower reliability

Question 7

Describe research into duration of STM?

Answer 7

• Peterson and Peterson (1959) tested 24 students by giving them a consonant syllable to remember
• They then had to count down for a 3 digit number given to them and at varying intervals they would be asked to recall the word aloud
• After 3 seconds about 80% could remember the syllable
• After 18 seconds only 3% could
• So they concluded that STM duration is about 18 seconds without rehearsal

Question 8

Describe research into duration of LTM:

Answer 8

• Bahrick (1975) studies just under 400 participants aged from 17 to 74
• He obtained high school year books and did a photo-recognition test (50 photos) and a free recall test
• If within 15 years of graduation they were about 90% accurate in photo recognition
• After 48 years it declines to about 70%
• Free recall was less accurate than photo recognition showing that some LTM can last up to a lifetime

Question 9

What’s a strength and a limitation of Peterson and Peterson’s, and Bahrick’s research into duration?

Answer 9

• Strength that Bahrick et al’s study has high external validity as researchers investigated meaningful memories which increases recall rates
• Limitation that Peterson and Peterson’s study the stimulus was artificial meaning the study was irrelevant and meaningless material making it harder to remember - lack of external validity