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

Question 1

What is memory?

Answer 1

Memory is the process by which information is encoded, stored and retrieved.

Question 2

What is the STM?

Answer 2

STM stands for Short Term Memory which stores and allows recall of information for a period of several seconds up to 30 seconds without rehearsal. It’s capacity is very limited.

Question 3

What is the LTM?

Answer 3

LTM stands for Long Term Memory which stores and enables us to recall information from the more distant past. It’s capacity is unlimited and duration is potentially a lifetime.

Question 4

What are three ways in which the STM and LTM are different?

Answer 4

Duration
Capacity
Encoding

Question 5

What is Duration?

Answer 5

A measure of how long information can be stored for / how long information lasts.

Question 6

What is the Duration of the STM like?

Answer 6

Short term memories do not last long. To keep information in our STM, we must rehearse the information over and over again in order to keep the information active. (The maximum Duration of the STM is 18-30 seconds)

Question 7

Who researched the Duration of the STM? When?

Answer 7

Peterson and Peterson (1959)

Question 8

Describe Peterson and Peterson’s experiment to research the Duration of the STM:

Answer 8

1 24 Participants were presented with a consonant trigram.
2 To stop them from rehearsing the consonant trigram, and stopping the information form remaining active, participants were asked to count backwards in threes.
3 After a particular time interval e.g. 3 seconds, participants were asked to repeat the trigram that they had previously heard
4 This was repeated using different intervals with different consonant trigrams up to a 18 second interval

Participants could recall 90% of the consonant trigrams after 3 seconds.
Participants could recall 20% of the consonant trigrams after 9 seconds.
Participants could recall LESS THAN 10% of the consonant trigrams after 18 seconds.

Therefore, it is clear that in the STM, information decays very quickly if it is not kept active by rehearsing it. Peterson and Peterson suggested, from their research, that the maximum duration of the STM is 18 seconds. However, due to recent research, the STM’s maximum duration is between 18-30 seconds.

Question 9

What are 2 strengths and 2 weaknesses of Peterson and Peterson’s research?

Answer 9

+ Lab experiment where variables are highly controlled for example, how many consonant trigrams are presented - this means that only the Duration of the STM (time intervals) is being measured

+ reliable as it can easily be replicated as it is a standardised experiment where participants are simply shown consonant trigrams at different time intervals

• lacks ecological validity (artificial setting as a lab experiment and artificial task where pps had to remember consonant trigrams) as it doesn’t reflect real life meaning that it cannot be generalised.
• the trigrams presented first may confuse the participants when trying to remember the next trigrams in later trials - perhaps forgetting the consonant trigrams wasn’t due to just forgetting, but due to them confused them with other consonant trigrams

Question 10

What is the Duration of the LTM like?

Answer 10

Once information enters the LTM, it will remain in their for an individual’s lifetime.

Question 11

Who researched the Duration of the LTM? When?

Answer 11

Bahrick et al (1975)

Question 12

Describe Bahrick’s experiment to research the Duration of the LTM:

Answer 12

Bahrick asked 400 American participants, between the age of 17-74, whether they could remember their former classmates by asking them to identify pictures, matching names to pictures and recalling names without a picture (a cue).

Bahrick discovered that even after 48 years, participants were 70% accurate when asked to link names to faces on a picture.
However, without a cue e.g. a picture with a classmate on it, after 48 years, participants could only recall the names of their former classmates 30% of the time.

The study supports the view that the duration of the LTM is a lifetime as 48 years on, people could still recall information e.g. their former classmates’ names. The study also showed that cues are an effective way of triggering our memory/retrieval from the LTM due to cues helping the participant in Bakrick’s study remembering classmates’ names 40% more of the time.

Question 13

What is 1 strength and 2 weaknesses of Bahrick’s research?

Answer 13

+ It was a natural experiment as the material was meaningful and not artificial meaning that the experiment has high ecological validity e.g. recalling names is a task that could occur in everyday life.

• Due to it being a natural experiment, there is low control over the IV where a confounding variable may occur (something that has affected the DV e.g. the Duration of the LTM) for example, some of the former classmates’ names may have been rehearsed prior to the experiment meaning that perhaps the Duration wasn’t as long as 48 years, but a different Duration, making the research potentially invalid.
• Only specific information, that is particularly meaningful and likely to be well rehearsed, e.g. names of classmates was looked at - perhaps not all the information in the LTM will be easily as retrievable/accessible/easy to remember.

Question 14

What is Capacity?

Answer 14

The measure of how much information can be stored.

Question 15

What is the Capacity of the STM like?

Answer 15

5-9 items (7+-2)

Question 16

Who researched the Capacity of the STM? When?

Answer 16

Jacobs (1887)

Question 17

Describe Jacobs’ experiment to research the Capacity of the STM:

Answer 17

He developed the ‘serial digit span technique’ where 4 digits were read out to a participant which they had to repeat back. Another digit was then added to the current digits until the participant could not repeat back the digit string correctly.

Jacobs discovered that 9 digits and 7 letters were accurately recalled.
Jacobs discovered that capacity increased with age (digit span for 8 year olds was only 6, on average) due to the development of new techniques, like chunking, brain capacity increasing with age.
Jacobs discovered that digits were easier to remember as there were only 10 as there are 26 letters.

Question 18

What are 2 strengths and 2 weaknesses of Jacobs’ research?

Answer 18

+ has temporal validity as the study was repeated recently and produced the same results (can be applied to today’s society)
+ reliable as the study was replicated and produced the same results
- lacks ecological validity as repeating numbers is a very artificial task, and not one that we would do in everyday life
- as the study was carried out a long time ago, it is unknown whether extraneous variables (things that could affect the DV e.g. amount of sleep) we’re properly controlled

Question 19

What did Miller introduce about the Capacity of the STM?

Answer 19

Miller introduced “The magical number 7+-2)” to describe the capacity of the STM and also concluded that the technique ‘chunking’ can increase the capacity of the STM.

Question 20

What is the Capacity of the LTM like?

Answer 20

Unlimited

Question 21

What is Coding?

Answer 21

Coding is the form in which information is coded in.

Question 22

There are 3 ways in which information can be coded in. What are they?

Answer 22

1 Acoustic coding - storing information by how it sounds
2 Semantic coding - storing information according to its meaning
3 Visual coding - storing information by how it looks

Question 23

What is the coding for the STM/LTM? (How is information stored in the STM/LTM?)

Answer 23

STM - acoustic coding (sound form)

LTM - semantic coding (in terms of its meaning)

Question 24

Who researched Coding? When?

Answer 24

Baddeley (1996)

Question 25

Describe Baddeley’s experiment to research the Coding of the STM and LTM:

Answer 25

Baddeley showed participants a sequence of 5 words, under 1 of 4 different conditions, which they then had to write them down.

The 4 conditions were:
Acoustically similar (sound the same)
Acoustically dissimilar (sound different)
Semantically similar (have similar meanings)
Semantically dissimilar (have different meanings)

When tested immediately (STM), participants could remember the acoustically similar words the worst.
When tested 20 minutes later (LTM), participants could remember the semantically similar words the worst. Information is best coded in the STM, acoustically, where we therefore find acoustically similar words more difficult to remember as they sound the same and it is harder to differentiate between particular words. Information is best coded in the LTM, semantically, where we find therefore find semantically similar words more difficult to remember as they mean the same things and it can be harder to differentiate between particular words.

Question 26

What are 2 strengths and 1 weakness of Baddeley’s study?

Answer 26

+ lab experiment meaning that there is a good control over variables where only the DV (measuring how information is coded in the STM and LTM) is being measured. Therefore, the study is measuring what it intended to measure and is valid.

+ lack experiments can easily be replicated meaning that the study is reliable. (Can easily give participants a list of words under 4 conditions etc;)

• lacks ecological validity due to it being a lack experiment (artificial setting and artificial task (remembering a list of words)) which do not reflect real life and cannot be generalised to the wider population in the real world.

Question 27

How else can information be stored in the STM and LTM?

Answer 27

Visually