Lesson 1 - Coding, Capacity, and Duration of STM and LTM

Question 1

What is the Short Term Memory (STM)?

Answer 1

Short term memory is a memory store that allows the recall of information for a period of several seconds without rehearsal.

Question 2

What is Long Term Memory (LTM)?

Answer 2

Long term memory is a memory store that enables us to recall information from the more distant past.

Question 3

What are the 3 main differences between LTM and STM?

Answer 3

Duration
Capacity
Coding

Question 4

What is the duration?

Answer 4

It is a measure of how long information can be stored for.

Question 5

What is the capacity?

Answer 5

The measure of how much information can be held or stored.

Question 6

What is coding?

Answer 6

Coding is the form in which information is stored in the memory.
There are 3 possible ways of coding:
Acoustic,
Semantic,
Visual.

Question 7

What are the 3 characteristics of the LTM?

Answer 7

Duration: A lifetime
Capacity: Infinite
Coding: Semantic

Question 8

What are the 3 characteristics of the STM?

Answer 8

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

Question 9

Who did the study on STM duration?

Answer 9

Peterson and Peterson (1959)

Question 10

What was the methodology of Peterson and Peterson’s study?

Answer 10

There were 24 undergraduate students.
They were presented with a consonant trigram (e.g. GFP).
After counting to different numbers (3, 6, 9, 12, 15, 18) and then were told to recall the consonant trigram.

Question 11

What were the results of Peterson and Peterson’s study?

Answer 11

90% of PPs could remember after 3 seconds.
20% after 9 seconds.
Less than 10% after 18 seconds.
Information disappears extremely quickly if it cannot be rehearsed.

Question 12

Evaluation of Peterson and Peterson’s study - Lab experiment

Answer 12

It is a lab experiment so there is high control over variables.

Question 13

Evaluation of Peterson and Peterson’s study - repeatable

Answer 13

This study is a repeatable study as it can be done on many participants very easily, due o it’s simplicity.

Question 14

Evaluation of Peterson and Peterson’s study - Low ecological validity

Answer 14

Trying to remember consonant trigrams is a stupid task.

Question 15

Who tested the duration of the long term memory?

Answer 15

Bahrick (1975)

Question 16

What was the method of Bahrick’s study?

Answer 16

He tested using 400 American participants aged 17-74.
He asked if they could remember former classmates via pictures, matching names to pictures, and recalling names with no picture cue.

Question 17

What were Bahrick’s findings?

Answer 17

Even after 48 years, when they were asked to link names and faces, accuracy was 70%.
When participants were asked to free recall the names of their classmates, and this had an accuracy of 30%.

This shows that long term memories can last a lifetime.

Question 18

Evaluation of Bahrick’s study - Natural experiment

Answer 18

Bahrick’s study was a natural experiment that utilised meaningful material, so it has higher ecological validity than Peterson’s study.

Question 19

Evaluation of Bahrick’s study - less control of the experiment

Answer 19

Due to the study being a natural experiment, the experimenter had less control, and it is likely that some of the names had since been rehearsed e.g. classmates could still be in touch.

Question 20

Evaluation of Bahrick’s study - Issues with using names

Answer 20

Names are a very specific type of information, and they are repeated many times. It is likely that due to the regular rehearsal of them, they are easier to remember. Not all LTMs remain for a lifetime.

Question 21

Who measured the capacity of the STM?

Answer 21

Jacobs (1887)

Question 22

What was Jacobs’ method?

Answer 22

He developed the serial digit span technique. The researcher read out 4 digits and the participant was then asked to repeat it back. Another digit was then added, until the participant could not repeat it accurately.

Question 23

What were Jacobs’ findings?

Answer 23

He found that about 9 digits and 7 letters were correctly recalled. This capacity increased with age until they were an adult. Digits may be easier to recall, as there are only 10 unique digits, but 26 letters.

Question 24

Evaluation of Jacobs’ research - lacks ecological validity

Answer 24

Jacobs’ research lacks ecological validity, as random number and letter strings are not a realistic task. More meaningful information may be recalled better.

Question 25

Evaluation of Jacobs’ research - previous sequences

Answer 25

Previous sequences recalled by participants may have confused them on later trials, so we don’t know if that factor became a confounding variable. This affected how the capacity of STM was measured.

Question 26

Evaluation of Jacobs’ research - Temporal Validity

Answer 26

Jacobs’ study lacks temporal validity, so we cannot be sure that the extraneous variables were controlled. However, the study has been repeated since, and the same results have been found.

Question 27

What was Miller’s conclusion on short term memory?

Answer 27

He found that the STM has a capacity of 7+-2 items.

Question 28

How did Miller suggest someone can increase their memory capacity?

Answer 28

Chunking. This is a process where people could remember 5 letters as well as they could remember 5 words. It is essentially breaking down information into chunks.

Question 29

Who tested coding?

Answer 29

Baddeley (1966)

Question 30

What was the method of Baddeley’s study?

Answer 30

Participants are shown a sequence of 5 words, under one of four conditions.
1) Acoustically similar word (e.g. map, mad, cap)
2) Acoustically dissimilar word (e.g. pen, cow, bug)
3) Semantically similar words (e.g. tall, high, broad)
4) Semantically dissimilar words (e.g. foul, thin, late)

Question 31

What were the results of Baddeley’s study?

Answer 31

When tested immediately, participants were least accurate with the acoustically similar words.
When tested 20 minutes later (to test LTM) participants were least accurate with semantically similar words.

This means information is coded acoustically in the short term, and semantically in the long term.

Question 32

Evaluation of Baddeley - Low ecological validity

Answer 32

The words were a meaningless list. Semantic coding may apply when the information is more meaningful. Baddeley’s study simply lacks real life application.