Coding, Capacity And Duration Of Memory

Question 1

Coding

Answer 1

Format in which information is stored in various memory stores

Question 2

Capacity

Answer 2

The amount of information that can be stored in a memory store

Question 3

Duration

Answer 3

Length of time information is held in memory

Question 4

Short term memory

Answer 4

Temporary memory store
Limited capacity - 7 +/- 2
Coded acoustically (sounds)
Duration - 18-30 seconds

Question 5

Long term memory

Answer 5

Permanent memory store
Unlimited capacity
Coded semantically (meanings)
Duration can be for a lifetime

Question 6

Research On Coding

Answer 6

Baddeley (1966B)

72 participants
4 groups
List of words to memorise

1. Acoustically similar
2. Acoustically dissimilar
3. Semantically similar
4. Semantically dissimilar

• Participants were shown original words and asked to recall in correct order
  Immediate recall- STM recall
  They did worse on acoustically similar words
• recall after 20 minute interval (LTM recall)
  They did worse with semantically similar words

Suggests information is coded semantically in LTM

Question 7

Evaluation of Research on Coding

Answer 7

1.Artificial Stimuli

• they used artificial stimuli rather than meaningful material
• the words had no personal meaning to the participants

2. Can’t be generalised for different tasks
3. Meaningful information may be coded semantically in STM for some tasks
4. Findings have limited application

Question 8

Research on Capacity

Digit Span

Answer 8

Jacobs (1887)

1. 4 digits participants had to recall aloud in order
2. if they got it correct 5 digits would be read out and so on
3. determines a persons digital span

Digits - 9.3 mean
Letters- 7.3 mean

Question 9

Digit Span Evaluation

Answer 9

Temporal Validity

1. The experiment was done a long time ago
   - Early research lacked adequate control
   - Confounding variables not controlled- results may not be valid as participants may have been distracted whilst being tested
2. However the experiment is repeatable and the evidence supports the study so it has validity

Question 10

Research on Capacity

Span of Memory and chunking

Answer 10

Miller ( 1956)

1. Noted most things came in 7
-
7 days of the week 
7 notes on musical scale 
7 deadly sins 

2. Span of memory (capacity ) in STM is 7 (+/-2)
3. People recall 5 words as well as they recall 5 letters via CHUNKING

Question 11

Chunking

Answer 11

Grouping sets of digit or letters into units or chunks

Question 12

Evaluation of chunking

Answer 12

1. Miller overestimated the capacity of STM
2. Cowan (2001)
   - reviewed other research and concluded capacity of STM IS 4 chunks

-3. suggests lower end of Millers estimate (5 items ) is more accurate than 7 items

Question 13

Duration of STM research

Answer 13

Peterson & Peterson (1959)

1. 24 undergraduates took part in all 8 trials
2. Had to remember a trigram (3 consonant syllable )
3. given a 3 digit number to count back from until told to stop ; so they wouldn’t mentally rehearse the trigram (it would increase their memory )
4. on each trial they were stopped at different amount of times (3,6,9,12,18) RETENTION INTERVAL
5. STM has very short duration (you forget the more time passes ) unless you verbally rehearse something

Question 14

Evaluation of Research on Duration of STM

Answer 14

1. Stimulus was artificial and meaningless
2. Lacks external validity
   - Does not reflect real-life memory activities
   - we try to remember meaningful things
3. However we do remember meaningless things such as phone numbers so study is not totally irrelevant

Question 15

Criticism of Peterson and Peterson

Answer 15

1. Spontaneous Decay
   - we forget things in STM because the memory trace disappears if not rehearsed
2. Displaced
   - STM has limited capacity and new information will push out what’s currently there
3. Peterson and Peterson made the participants count down during the retention interval

Question 16

Duration of LTM

Answer 16

Bahrick et al (1975)

1. 392 students
2. Ohio
3. 17-74
4. They had to recall people from their high school year books
   - PHOTO RECOGNITION ,50 photos, some from the participants yearbook
   - FREE RECALL, recalled the name of their graduating class
5. ACCURACY photo recognition
   - 15 years - 90%
   - 48 years - 70%
6. ACCURACY free recall
   - 15 years- 60%
   - 48 years- 30%
7. LTM can last very long

Question 17

Evaluation of Duration of LTM

Answer 17

1. High external validity
   Real life meaningful memories were studied
2. Shepard (1967)
   meaningless pictures to be remembered - LTM recall rate was lower
3. Confounding variables not controlled
   - participants may have rehearsed their memory of the years by looking at their yearbook photos