Chapter 2.1 - Coding, capacity and duration of memory

Question 1

What is short-term memory?

Answer 1

The limited-capacity memory store;
- coding is mainly acoustic (sounds)
- capacity is between 5 to 9 items on average
- duration is about 18 seconds

Question 2

What is long-term memory?

Answer 2

The permanent memory store;
- coding is mainly semantic(meaning)
- capacity is unlimited
- memories can be stored for up to a lifetime

Question 3

What is coding?

Answer 3

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

Question 4

What is capacity?

Answer 4

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

Question 5

What is duration?

Answer 5

The length of time information can be held in memory

Question 6

What is meant by acoustic?

Answer 6

Sounds

Question 7

What is meant by semantics?

Answer 7

Meanings

Question 8

Describe the research on coding

Answer 8

Alan Baddeley : 1966
- Four groups, group 1 and 2 based on acoustics, group 3 and 4 based on semantics, similar and dissimilar
- Each group was given a different list of words to remember
- They were shown the original words and asked to recall in the correct order

Question 9

What were the findings of the research on coding?

Answer 9

• When recalling from short-term memory, participants did worse with acoustically similar words after recalling immediately asked
• When recalling from long-term memory, 20 minutes, participants did worse with semantically similar words

Question 10

What did the findings on coding suggest?

Answer 10

That information is coded acoustically in STM and semantically in LTM

Question 11

What is a strength of the research on coding? (separate memory stores)

Answer 11

• It identified a clear difference between the two memory stores
• Helps understand the memory system, which led to the multi-store model

Question 12

What is a limitation on the research on coding? (artificial stimuli)

Answer 12

• The word lists used had no personal meaning to participants, findings aren’t relevant in everyday life
• people might use semantic coding even for STM tasks (meaningful info)
• Limited application

Question 13

Describe the research on capacity - digital span

Answer 13

Joseph Jacobs (1887):
- The researcher read out four digits and the participant recalled them aloud, if it was correct, the researcher reads out five digits and so on until the participant couldn’t recall the order correctly

Question 14

What were the findings of the research on capacity, digit span?

Answer 14

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

Question 15

What is a strength of the research on capacity? JACOB (valid study)

Answer 15

• It has been replicated
• Old study; lacks adequate controls - confounding variables
• Findings have been confirmed by other better controlled studies

Question 16

Describe the research on capacity - span of memory and chunking

Answer 16

George Miller(1956):
- Made observations of everyday practice

Question 17

What were the findings of the research on capacity, span of memory and chunking?

Answer 17

• He noted that things come in sevens, seven notes on the musical scale, seven days of the week, seven deadly sins etc.
• He thought that the span/capacity of STM is about 7 items, but also noted that people can recall five words really easily

Question 18

What did the findings on capacity, span of memory and chunking suggest?

Answer 18

It suggested that we remember things through the use of chunking - grouping sets of digits or letters into units

Question 19

What is a limitation of the research on capacity? MILLER (overestimated the capacity of STM)

Answer 19

• Reviewed research showed that the capacity of STM is 4+- 1 chunks
• Five items are more appropriate than seven items

Question 20

Describe the research the duration of STM

Answer 20

Margaret and Peterson(1959):
- 24 students with eight trials each
- The student was given a consonant syllable to remember as well as a 3-digit number
-They counted backwards from this number to prevent any mental rehearsal of the consonant syllable
- They were told to stop after varying periods of time 3, 6, 9, 12, 15 or 18 seconds(retention interval)

Question 21

What were the findings of the research on the duration of STM?

Answer 21

• After 3 seconds: average recall was 80%
• After 18 seconds: average recall was 3%

Question 22

What did the findings on the duration of STM suggest?

Answer 22

The duration of STM may be about 18 seconds, unless we repeat the information over and over(verbal rehearsal)

Question 23

What is a limitation on the research on duration for STM? (meaningless stimuli)

Answer 23

• Not completely irrelevant as we do remember some meaningless material sometimes
• Nonsense trigrams aren’t everyday memory activities
• Lacks external validity

Question 24

Describe the research the duration of LTM

Answer 24

Harry Bahrick (1975)
- 392 American participants ages between 17 and 74
- Photo-recognition test of 50 photos and free recall test where participants recalled all the names of their graduating class

Question 25

What were the findings of the research on the duration of LTM?

Answer 25

- Participants tested within 15 years of graduation were about 90% accurate in photo recognition - After 48, recall declined to about 70% - Free recall : 60% after 15 years and 30% after 48 years

Question 26

What did the findings on the duration of LTM suggest?

Answer 26

That long term memory may last up to a lifetime for some material

Question 27

What is a strength on the research on duration for LTM? (high external validity)

Answer 27

- Investigated meaningful memories - Meaningless memory studies resulted in lower recall rates - More real estimate on the duration of LTM