Memory : Coding, Capacity and Duration

Question 1

What’s duration of memory?

Answer 1

The length of time information can be stored in memory

Question 2

What’s capacity of memory?

Answer 2

The amount of information that can be stored in memory

Question 3

What’s coding of memory?

Answer 3

Memory encoding is a process where sensory info is modified and stored in the brain (most common forms are visual, acoustic and semantic)

Question 4

What’re the different types of memory stores?

Answer 4

SM, STM, LTM

Question 5

What’s SM?

Answer 5

Sensory memory → initial contact for stimuli

Question 6

What’s STM?

Answer 6

Short term memory → the info we’re currently aware of/ thinking about. Info will decay if not rehearsed and retrieved (new info pushes out old info → displacement)

Question 7

What’s LTM?

Answer 7

Long term memory → continual storage of info which is largely outside our awareness

Question 8

What’s the capacity of SM?

Answer 8

Very large → like recording with your senses

Question 9

What’s the capacity of STM?

Answer 9

Limited capacity (between 7 +/- 2 items)

Question 10

What’s the capacity of LTM?

Answer 10

Potentially unlimited capacity (haven’t discovered a limit yet)

Question 11

What did Jacob’s research?

Answer 11

Jacobs (1887) was one of the first to use the digit span test to assess the capacity of STM. He found the average span for numbers is 9.3 items, and letters decreased to 7.3 items

Question 12

What did Miller’s research?

Answer 12

George Miller (1956) reviewed physiological research and concluded that “the magic number is 7 plus or minus two” (we can best remember 5-9 items) → people old recall around 7 dots, 7 letters, 7 musical notes

He also found that by chunking info our capacity for remembering info can be increased if we chunk items together → if we find links between things and group them together, we can remember more

Question 13

How is info chosen to be converted to STM?

Answer 13

Selective memory (only converts what is seen/ focused on)

Question 14

What’s the digit span test?

Answer 14

Number recall test where individuals see how many digits they can immediately recall (can be done forwards or backwards)

Question 15

What’s a disadvantage of the digit span test?

Answer 15

Lacks ecological validity

Question 16

What’s sub vocal articularity rehearsal?

Answer 16

Repeating something in your head

Question 17

What’re the disadvantages of Miller’s research?

Answer 17

• he may have overestimated the capacity
• he didn’t specify the size of the chunk
• the capacity isn’t the same for everyone (individual differences)
• lacks ecological validity

Question 18

Peterson & Peterson (1959) - Aim

Answer 18

To investigate the duration of STM

Question 19

Peterson & Peterson (1959) - Procedure

Answer 19

• 24 Uni students
• 8 trials
• Ps were given a consonant trigram (3 letters) and a 3-digit number and were asked to recall the letters after intervals of 3, 6, 9, 12, 15 or 18 secs. To prevent rehearsal, Ps were asked to count backwards from 100 in 3s

Question 20

Peterson & Peterson (1959) - Findings

Answer 20

3 secs - 80% successful recall
9 secs - 20% successful recall
18 secs - less than 10% successful recall

Question 21

Peterson & Peterson (1959) - Conclusion

Answer 21

The duration of STM is less than 18 secs

Question 22

Peterson & Peterson (1959) - Disadvantages

Answer 22

• may not been measuring decay, but actually displacement (lowers construct validity)
• lacks ecological validity
• counting backwards changes individuals focus onto numbers vs the letters → sub vocal articulatory rehearsal for numbers not letters

Question 23

Bahrick et al (1975) - Aim

Answer 23

To investigate duration of LTM

Question 24

Bahrick et al (1975) - Procedure

Answer 24

• 392 Ps from the Us aged 17-74
• some tested with photo recognition and some with free name recall from their highschool yearbook

Question 25

Bahrick et al (1975) - Findings

Answer 25

Photo recognition → Ps tested within 15 years or graduation were 90% accurate, after 48 years declined to 70%
Free recall → after 15 years 60% accurate, after 48 years 30% accurate

Question 26

Bahrick et al (1975) - Conlcusion

Answer 26

The duration of LTM can last a very long time (longer than STM)

Question 27

Bahrick et al (1975) - Advantages

Answer 27

• high ecological validity (remembering names and faces done in everyday life)

Question 28

Bahrick et al (1975) - Disadvantages

Answer 28

• may lack internal validity (some may have looked through yearbook on own time)
• compromises the IV (e.g. changes from 15 years to 2 weeks)

Question 29

Baddeley (1966) - Aim

Answer 29

To establish whether STM and LTM encode info differently

Question 30

Baddeley (1966) - Procedure

Answer 30

Ps were shown a list of words and asked to recall them in the correct order. To test STM, Ps recalled words immediately after hearing them. To test LTM, a time interval of 20 mins was given.
E.g.
Group 1 cat, cab, can acoustically similar
Group 2 pit, few, cow acoustically dissimilar
Group 3 great, large, big semantically similar
Group 4 good, huge, hot semantically dissimilar

Question 31

Baddeley (1966) - Findings

Answer 31

Acoustically similar words
STM → no difficulty immediately
LTM → difficulty after 20 mins

Semantically similar words
STM → difficulty immediately
LTM → no difficulty after 20 mins

Question 32

Baddeley (1966) - Conclusion

Answer 32

Info is coded acoustically in STM and semantically in LTM

Question 33

Baddeley (1966) - Advantages

Answer 33

• found there are distinct and separate memory stores

Question 34

Baddeley (1966) - Disadvantages

Answer 34

• there is contradictory research evidence
• lacks ecological validity