Coding, Capacity & Duration of Memory

Question 1

What is coding?

Answer 1

The process of converting information from one form to another

Question 2

What did Baddeley’s study into coding involve?

Answer 2

• he gave different lists of words to 4 groups of pps to remember & recall them in the correct order:
• Group 1: acoustically similar - sound the same
• Group 2 : acoustically dissimilar - sound different
• Group 3: semantically similar - similar meanings
• Group 4: semantically dissimilar - different meanings

Question 3

What were the findings of Baddeley’s study?

Answer 3

• when they had to recall the words immediately after hearing it (STM) they did worse with acoustically similar words
• when pps were asked to recall after 20 mins (LTM) they did worse with semantically similar words
• shows that info is coded semantically in the LTM

Question 4

What is capacity?

Answer 4

The amount of info that can be held in a memory store

Question 5

What was Jacobs’ (1887) study into capacity?

Answer 5

• he developed a technique to measure digit span
• researcher gives pps 4 digits which they are asked to recall in the right order out loud
• if remembered correctly the researcher gives 5 digits & so on until pps can’t recall correctly which determines their digit span
• Jacobs found that the mean span across all pps was 9.3 numbers & 7.3 for mean span of letters

Question 6

What was Miller’s (1956) contribution to research on capacity?

Answer 6

• he made observations of everyday practice & noted that things come in 7s e.g. 7 days of the week, 7 notes on musical scale etc.
• this suggests that the capacity of STM is around 7 items
• Miller also noted that people can recall 5 words & 5 letters by chunking groups of digits or letters into separate units

Question 7

What is duration?

Answer 7

The length of time information can be held in memory

Question 8

What was the Petersons’ (1959) study on the duration of the STM?

Answer 8

• they tested on 24 undergraduates who took part in 8 trials
• on each trial was given a consonant syllable/trigram & a 3-digit number
• they were asked to count backwards from the trigram until told to stop which prevented any mental rehearsal
• on each trial they were told to stop for a different amount of time increasing by 3 seconds - retention interval
• it suggests that STM has a very short duration unless something is constantly repeated

Question 9

What was Bahrick et al.’s (1975) study on the duration of LTM?

Answer 9

• they studied 392 pps from Ohio aged 17-74
• high school yearbooks of the pps were obtained & their recollection was tested by photo-recognition tests or free recall tests
• pps tested within 15 years of their graduation were around 90% accurate
• after 48 years there was 70% accuracy of photo recognition (free call was less good than photo recognition)
• shows that LTM lasts a very long time

Question 10

Evaluation: Separate memory stores (coding)

Answer 10

• Baddeley’s study identified a clear difference between the 2 memory stores
• the idea that the STM mainly uses acoustic coding & LTM uses semantic coding has been tested for in the study
• this was an important step into understanding the memory system which led to multi-store model

Question 11

Evaluation: Artificial stimuli (coding)

Answer 11

• Baddeley’s study used artificial stimuli rather than meaningful material
• word lists had no meaning to pps
• this means we should be careful when generalising findings to diff kinds of memory tasks
• e.g. when processing meaningful info people may use semantic coding for STM tasks
• suggests that findings from Baddeley’s study has limited application

Question 12

Evaluation: A valid study (capacity)

Answer 12

• Jacobs’ study has been replicated
• Jacobs’s study is quite old however have been confirmed by other, better controlled studies by Bopp & Verhaeghen (2005)
• suggests that Jacobs’ study on digit span in STM has validity

Question 13

Evaluation: Not so many chunks (capacity)

Answer 13

• Miller may have overestimated STM capacity
• Cowan reviewed other research & concluded
  that the capacity of STM is only around + or - 1 from 4
• suggests that the lower end of Miller’s estimate (5 items) is more appropriate than 7

Question 14

Evaluation: Meaningless stimuli in STM study (duration)

Answer 14

• the stimulus material in the Peterson’s study was artificial
• recalling consonant syllables doesn’t reflect everyday memory activity where we try to remember meaningful information
• this means the study lacked external validity

Question 15

Evaluation: High external validity (duration)

Answer 15

• Bahrick et al’s study has high external validity
• researchers investigated meaningful memories like people’s names & faces
• recall rates were lower with studies conducted on LTM with meaningless pictures
• suggests that Bahrick et al’s findings reflect a more ‘real’ estimate of duration of LTM