Capacity, Duration and Coding of Memory

Question 1

What are the 3 rules for memory experiments?

Answer 1

1. Order of recall is marked as correct recall.
2. Interference tasks are used to avoid rehearsal of original item of test.
3. Non sense consonants/syllables are used e.g., trigrams to truly test memory (TXH OR GTB), this is to avoid meaningful associations.

Question 2

What is Short-term memory?

Answer 2

A limited capacity memory store. Mainly acoustic (sounds) coding, and the capacity is between 5 to 9 items, and duration is 18 seconds.

Question 3

What is Long-term memory?

Answer 3

A permanent memory store. Coding is semantic (meaning) and there is limited capacity for a life time.

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 a memory store.

Question 6

What is Coding?

Answer 6

The format in which information is stored in the various memory stores (Semantic, Visual, Acoustic).

Question 7

What does Semantic, Visual, Acoustic mean?

Answer 7

Semantic = Meaning of words e.g. big means the same as large
Visual = What the word looks like e.g. upper case letters
Acoustic = What the word sounds like e.g. cat rhymes with mat

Question 8

What research into coding did Baddeley (1966a/b) do?

Answer 8

Gave different lists of words to four groups of participants to remember.
Group 1: acoustically similar words - cat, sat, mat
Group 2: acoustically dissimilar words - pit, few, cup
Group 3: semantically similar words - great, large, big
Group 4: semantically dissimilar words - huge, hot, small, cold
After hearing the words the ppts were then immediately shown the original words in the wrong order and asked to recall them in the correct order (STM).
For LTM, ppts had a 20 minute interval before recall in which they performed another task to prevent rehearsal.

Question 9

What are the findings and conclusion of Baddeley’s research into coding?

Answer 9

For STM they tended to worse with acoustically similar words and for LTM they tended to worse with semantically similar words.
This means that STM uses acoustic coding and LTM uses semantic coding.

Question 10

What is a strength of Baddeley’s research into coding?

Answer 10

His research makes ‘cognitive sense’ as there are separate memory stores. To remember something for a short period of time we tend to repeat it aloud to ourselves. To remember something for longer periods of time we tend to remember the general meaning rather than exactly what happens.

Question 11

What is a limitation of Baddeley’s research into coding?

Answer 11

This study used artificial stimuli rather meaningful memory tasks, e.g., the word lists were not meaningful. It is therefore difficult to generalise the findings to real life situations involving memory.
Lack ecological validity.

Question 12

What is another limitation of Baddeley’s research into coding?

Answer 12

Information can be coded other ways, for example; visually, taste, smell.
This means the findings have limited application.

Question 13

What research did Jacobs (1886) do into the capacity of STM?

Answer 13

Jacob used the digit span technique in his laboratory experiment to assess the capacity of STM. He found the average span of capacity for digits was 9.3 and 7.3 for letters.

Question 14

What research did Miller (1956) do into the capacity of STM?

Answer 14

Miller reviewed psychological research and concluded that the span of immediate memory is on average 7 items.
He concluded this by observing everyday practices, for example; things that come in 7s (7 days of the week, 7 deadly sins, 7 notes on a musical scale). He developed ‘The magic number 7+/-2’.
He also noticed how people can recall 5 letters, this is by chunking (grouping sets of digits or letters into chunks).

Question 15

What are the strengths of Jacob’s capacity research?

Answer 15

It is a valid study as it is supported by other research.
Also this research has been replicated.
It was a controlled experiment.

Question 16

What are the limitations of Jacob’s capacity research?

Answer 16

There are other factors that influence STM capacity, the research by Jacob is a very old study and it may have lacked control. The participants may have not performed as well as they could have, there may have been confounding variable, for example; noise.

Question 17

What are the strengths of Miller’s capacity research?

Answer 17

Miller’s magic number 7+/-2 (1956) supports the validity of Jacob’s research.
It has been replicated.
It is a controlled experiment.

Question 18

What are the limitations of Miller’s capacity research?

Answer 18

Miller may have had an overestimation of capacity. Cowan (2001) reviewed his research and found that the capacity of STM was 4+/-1 chunks of information. The lower end of Miller’s estimate is more appropriate to use.

Question 19

What research did Peterson and Peterson do into the duration of STM?

Answer 19

In 1959 Peterson and Peterson studied 24 students, each ppt was tested over 8 trials. On each trial a ppt was given a consonant syllable and a three digit number (e.g. BGY 512). They were asked to recall that consonant syllable after an interval of 3 seconds, were they had start counting backwards from their 3 digit number. This process is repeated for each ppt and for 6,9,12,15,18 second intervals.
After 3 seconds, ppts were 80% correct, after 9 seconds, they were 20% correct and after 18 seconds, they were 3% correct. This means STM has a very short duration of less than 18 seconds if verbal rehearsal is prevented.

Question 20

What research did Bahrick do into the duration of LTM?

Answer 20

In 1975 Bahrick tested 400 people aged 17-74 on their memory of their classmates. A photo recognition test consisted of 50 photographs, some from the schools high school yearbook. In a free-recall test ppts were asked to list names they could remember in their graduating class. Ppts tested within 15 years years of graduation were about 90% accurate for photo recognition and 60% accurate on free recall. After 48 years, this declined to about 70% for photo recognition and 30% on free recall.

Question 21

What are the strengths of Peterson and Peterson’s duration of STM study?

Answer 21

The study has been replicated and the findings were also replicated.
The study was highly controlled; the use of trigrams - all ppts could not impose any meanings and they have the same difficulty level.

Question 22

What are the limitations of Peterson and Peterson’s duration of STM study?

Answer 22

The study lacks ecological validity, it is not representative of real-life learning, for example; laboratory use of trigrams.
Additional cognitive task = counting backwards may have affected recall.

Question 23

What are the strengths of Bahrick’s study on LTM duration?

Answer 23

It has experimental support. The findings support those of Shephard (1967), who demonstrated people’s LTM for adverts.
It has high ecological validity. It involved people’s real life memories rather than nonsense in the laboratory.

Question 24

What are the limitations of Bahrick’s study on LTM duration?

Answer 24

It lacked some important controls.
E.g. Ppts may have been in contact with friends or looked at the year book since they left school.