Coding, capacity and duration of memory

Question 1

short term memory

Answer 1

the limited capacity memory store. In STM, coding is mainly acoustic, capacity is between 5 and 9 items on average, duration is about 10 seconds

Question 2

long term memory

Answer 2

the permanent memory store. In LTM, coding is mainly semantic, it has unlimited capacity and can store memories for up to a lifetime

Question 3

coding

Answer 3

the format in which information is stored in the various memory stores

Question 4

capacity

Answer 4

the amount of information that can be held in a memory store

Question 5

duration

Answer 5

the length of time information can be held in the memory

Question 6

who researched into the coding of memory ?

Answer 6

Alan Baddeley

Question 7

what were the four groups in Baddeley’s research ?

Answer 7

-group 1, acoustically similar (words sounding similar, e.g. cat, cab, can)
- group 2, acoustically dissimilar (words sounding different, e.g. pit, few, cow)
- group 3, semantically similar (words with similar meanings, e.g. great, large, big)
- group 4, semantically dissimilar (words with different meanings, e.g. good, huge, hot)

Question 8

what was Baddeley’s procedure ?

Answer 8

1. ppt were shown the original words and asked to recall in the correct order
2. when they did this task immediately, recalling from STM, they tended to do worse with acoustically similar words
3. when they recalled the word list after a time interval of 20 minutes, recalling from LTM, they did worse with the semantically similar words

Question 9

who tested memory capacity with the digit span research ?

Answer 9

Joseph Jacobs

Question 10

what was Jacob’s procedure ?

Answer 10

researcher reads out repeatedly digits until the ppt cannot recall the order correctly - indicates the individual’s digit span

Question 11

what was Jacob’s findings ?

Answer 11

• the mean span for digits across all participants was 9.3 items
• the mean span for letters was 7.3

Question 12

who tested memory capacity through observations ?

Answer 12

George Miller

Question 13

what did George observe and find ?

Answer 13

• observed everyday things
• noticed things came in seven
• e.g. notes on a musical scale, days of the week, deadly sins

Question 14

what was George’s conclusions ?

Answer 14

capacity of STM is 7 +/- 2
five words can be recalled as easily as five letters. this is chunking

Question 15

who researched the duration of STM ?

Answer 15

Peterson and Peterson

Question 16

what were Peterson and Peterson’s procedure ?

Answer 16

• 24 students in eight trials
• each trials students were given a consonant syllable
• also given a 3-digit number
• counted back from the 3 digit number until asked to stop
• each trial they stopped for varying periods of time, 3,6,9,12,15 or 18

Question 17

what were Peterson and Peterson’s findings ?

Answer 17

• after 3 seconds, average recall was 80%
• after 18 seconds, average recall was 3%
• suggests STM duration is around 18 seconds, unless we rehearse

Question 18

who researched the duration of LTM ?

Answer 18

Bahrick et al (1975)

Question 19

what was Bahrick’s procedure ?

Answer 19

• 392 American participants ages between 17 and 74
• high school yearbooks obtained from the participants
• recall tested in carious ways;
  1. photo recognition test consisting of 50 photos, some from participants’ high school yearbooks
  2. free recall test where participants recalled the all the names of their graduating class

Question 20

what were Bahrick’s findings ?

Answer 20

• participants tested within 15 years of graduation were about 90% correct in photo recognition
• after 48 years, recalldeclined to about 70%
• free recall was less accurate. 60% after 15 years, 30% after 48 years

Question 21

what was Bahrick’s conclusion ?

Answer 21

shows that LTM may last up to a lifetime

Question 22

strength - what does separate memory stores do for Baddeley’s study?

Answer 22

P: clear difference between two memory stores
E: later research showed that there are exceptions to Baddeley’s findings
E: but the idea that STM mostly semantic has stood the test of time
L: important step in our understanding of the memory system, led to the multi-tore memory model

Question 23

limitation - what does artificial stimuli do to Baddeley’s study?

Answer 23

P: used artificial stimuli instead of meaningful material
E: had no personal meaning to participants so may not tell us much about coding in different kinds of memory tasks, especially everyday life
E: when processing more meaningful information, people may use semantic coding even for STM tasks
L: suggests that findings from this study have limited application - lack ecological validity

Question 24

strength - what does validity do for Jacob’s study?

Answer 24

P: has been replicated- very
told and early research often lacks adequate controls
E: e.g. some participants’ digit spans may have been underestimated because they were distracted (confounding variables)
E: despite this, Jacobs’ findings have been confirmed by other, better controlled studies
L: temporal validity

Question 25

limitation - what does overestimation do to Miller’s research?

Answer 25

P: may have overestimated STM capacity
E: Cowan reviewed other research and concluded that the capacity of STM is only about 4 +/- 1 chunks
E: suggests that the lower end of Miller’s estimate is more appropriate that 7 items

Question 26

limitation - what does a meaningless stimuli do to Peterson & Peterson’s study?

Answer 26

P: material was artificial
E: not completely irrelevant because we do sometimes try to remember fairly meaningless material
E: even so, recalling consonant syllables does not reflect most everyday memory activities where we are trying to remember is meaningful
L: means the study lacked external validity

Question 27

strength - what does high external validity do for Bahrick et al’s findings?

Answer 27

P: high external validity because the researchers investigated meaningful memories
E: when studies om LTM were conducted with meaningless pictures to be remembered, recall rates were lower
E: suggests that Bahrick et al’s findings reflect a more ‘real’ estimate of the duration of LTM