Coding, Capacity and Duration

Question 1

What is coding?

Answer 1

The format information is stored

Question 2

What is duration?

Answer 2

The length of time information is held for

Question 3

What is capacity?

Answer 3

The amount of information that can be stored

Question 4

What is the coding, capacity and duration of STM?

Answer 4

Coding: Acoustic
Capacity: 7+/- 2 items
Duration: 18 seconds

Question 5

What is the coding, capacity and duration of LTM?

Answer 5

Coding: Semantic
Capacity: Unlimited
Duration: A lifetime

Question 6

What is the coding, capacity and duration of the sensory register?

Answer 6

Coding: According to sense
Capacity: small
Duration: limited (milliseconds)

Question 7

What is a research study which shows evidence for the coding in STM and LTM?

Answer 7

Baddeley (1966)

Question 8

What is a research study which shows evidence for the capacity of STM?

Answer 8

Jacobs (1887)

Question 9

What is a research study which shows evidence for the duration of STM?

Answer 9

Peterson and Peterson (1959)

Question 10

What Baddeley’s study of coding in the STM and LTM?

Answer 10

• Gave different lists of words to 4 groups of ptpts to remember:

Group 1- words acoustically similar (e.g. cat, cab, can)

Group 2- Words acoustically different (e.g. pit, few, cow)

Group 3 - Words with similar meaning (great, large, big)

Group 4 - Words with different meanings (e.g. good, huge, hot)
- Ptpts were shown original words and asked to recall them in correct order.

• When recalled verbally (recall from STM), they did worse with acoustically similar words.
• When recalled list after 10 minutes (recall from LTM), they did worse with semantically similar words.
• Info coded
  acoustic in SMT and
  semantic in LTM.

Question 11

What was Jacobs study of the capacity of the STM?

Answer 11

• 4 digits read out and ptpt recalls these out loud in correct order
• If correct researcher reads out 5 digits and so on until ptpts cannot recall order correctly= individual’s digit span
• Mean span for digits across all ptpts = 9.3 items
• Mean span for letters = 7.3

Question 12

What was Peterson and Peterson’s study of the duration of the STM?

Answer 12

• Nonsense trigrams (e.g. ZFB) given to ptpts
• Had to count backwards in threes from a large three-digit number (prevent mental rehearsal) for varying periods of times (after 3, 6, 9, 12, 15 or 18 seconds)
• Found 80% of trigrams were recalled correctly after 3 seconds
• Only 3% after 18 seconds
• Suggests STM duration= about 18 seconds

Answer 13

• 400 ptpts aged between 17 and 74 years- shown a set of photos and list of names (some random and some from old yearbook)
  -Asked to identify ex-school friends
• Those who left high school in last 15 years identified 90% of faces and names
• Those who’d left 48 years previously identified 80% of names and 70% of faces
• Suggests memory for faces= long lasting.

Question 14

What is the strength of the research on coding?

Answer 14

Consistent evidence- Baddeley’s findings that STM is coded acoustically and LTM semantically has stood the test of time= an important step in our understanding of the memory system which led to the multi-store model.

Question 15

What is the limitation of the research into coding?

Answer 15

Use of artificial materials- Issue with the stimuli used in the experiment not being meaningful material.
E.g. Word lists have no personal meaning to participants findings may not tell us much about coding in different kinds of memory tasks, especially in everyday life. When processing more meaningful information people may use semantic coding even for STM tasks= limited application.

Question 16

What is the strength of research into capacity?

Answer 16

Research has been replicated- Jacobs study is a very old one and early research in Psychology often lacked adequate controls.

E.g. some participants’ digit spans might have been underestimated because they were distracted during testing. However, Jacob’s findings have been confirmed by other, better controlled studies since the 1800s.
Suggests Jacobs’ study is a valid test of digit span in STM.

Question 17

What is the limitation of research into capacity?

Answer 17

Capacity overestimated- Cowan (2001) reviewed other research and concluded that capacity of STM is only about 4 (plus or minus 1) chunks

Question 18

What is the limitation of the research into duration?

Answer 18

Artificial stimuli- Peterson and Peterson= artificial materials. Recalling consonant syllables doesn’t reflect most everyday memory activities where what we are trying to remember is meaningful lacks external validity
Counter- Bahrick et al. study= high external validity. Researchers investigated meaningful memories (of people’s names and faces). When studies on LTM were conducted with meaningless pictures to be remembered, recall rates were lower. Bahrick et al.’s findings reflect a more ‘real’ estimate of the duration of LTM.