Memory - Types of Memory

Question 1

What are the key assumptions of Atkinson and Shiffrin (1968)’s multi-store model of memory?

Answer 1

• there are separate memory stores
• sensory register
• transfer from sensory register to short-term memory
• short-term memory
• transfer from short-term memory to long-term memory
• long-term memory

Question 2

What is the multi-store model?

Answer 2

The MSM describes how information flows through the memory system. Memory is made of three stores linked by processing.

Question 3

What are the sensory stores within the sensory register?

Answer 3

• iconic: visual (sight) sensory memory
• echoic: auditory (hearing) sensory memory
• haptic: tactile (touch) sensory memory
• olfactory: smell
• gustatory: taste

Question 4

What is the sensory register?

Answer 4

A stimulus from the environment passes into the sensory register along with lots of other sights, sounds etc. This part of memory is not one store but five, one for each sense.

Question 5

What is the duration, capacity and coding for the sensory register?

Answer 5

• Duration: very brief - less than half a second. Sperling found iconic store faded within one second and auditory memory lasts up to four seconds.
• Capacity: high, e.g. over one hundred million cells in one eye, each storing data. Sperling 1960 tested iconic store by flashing up a grid of letters and then testing recall immediately. Information was initially available but decayed before it could be recalled.
• Coding: depends on the sense - visual, auditory, etc. Sensory memory holds information long enough to warrant attention. Encoding is modality specific.

Question 6

How is information transferred from the sensory register to short-term memory store?

Answer 6

Little of what goes into the sensory register passes further into the memory system - needs attention to be paid to it.

Question 7

What is the short-term memory store?

Answer 7

STM is a limited capacity and duration store.

Question 8

What is the duration, capacity and coding for short-term memory?

Answer 8

• Duration: about 18 to 30 seconds unless the information is rehearsed. Information can be held indefinitely by rehearsal. Peterson and Peterson prevented rehearsal of nonsense trigrams by asking participants to count backwards. Recall fell to 5% after 18 seconds.
• Capacity: between 5 and 9 items before some forgetting occurs. Miller 7+/- 2. Cowan ‘magic 4’.
• Coding: Conrad 1964 presented participants with 5 consonants for less than a second. Mistakes were made when letters were acoustically similar, suggesting that encoding in short-term memory is acoustic.

Question 9

How is information transferred from the short-term memory to the long-term memory store?

Answer 9

Maintenance rehearsal occurs when we repeat (rehearse) material to ourselves. We can keep information in STM as long as we rehearse it. If we rehearse it long enough, it passes into LTM.

Question 10

What is the long-term memory store?

Answer 10

A permanent store. When we want to recall materials stored in LTM, it has to be transferred back to STM by a process called retrieval.

Question 11

What is the duration, capacity and coding for long-term memory?

Answer 11

• Duration: potentially up to a lifetime. Ebbinghaus 1885 memorised lists of nonsense syllables, then tested himself at intervals. Memory declined sharply at first, then levelled off after a few days.
• Capacity: there is no evidence or potential limit to LTMs capacity. However, memories are not always precise which suggests that some “pruning” to economise space may occur.
• Coding: Baddeley 1966 participants found it harder to recall semantically similar words compared to acoustically similar words, suggesting LTM is encoded semantically.

Question 12

What are the strengths of the multi-store model of memory?

Answer 12

• the MSM is supported by research showing STM and LTM are different
• it remains an influential model and is the starting point for much of the memory research that has followed

Question 13

What are the weaknesses of the multi-store model of memory?

Answer 13

• evidence suggests there is more than one type of STM
• it only explains one type of rehearsal
• research studies supporting the MSM use artificial materials
• it oversimplifies the long-term memory store

Question 14

What research is there to support STM and LTM being different?

Answer 14

Baddeley (1966) found that we tend to mix up words that sound similar when using our STMs. But we mix up words that have similar meanings when we use our LTMs.

This clearly shows that coding in STM is acoustic and in LTM it is semantic.

This supports the MSM’s view that these two memory stores are separate and independent.

Question 15

What evidence is there to suggest there being more than one type of STM?

Answer 15

Shallice and Warrington (1970) studied KF, a patient with amnesia. His STM for digits was poor when they read them out loud to him. But his recall was much better when he read the digits himself.

The MSM states that there is only one type of STM (unitary store). But KF study suggests theremust be one short-term store to process visual information and another to process auditory information.

The working memory model is a better explanation for this finding because it includes separate stores.

Question 16

Why is the MSM only explaining one type of rehearsal a weakness?

Answer 16

Craik and Watkins (1973) argued there are two types of rehearsal - maintenance and elaborative. Maintenance is the one described in the MSM.

But elaborative rehearsal is needed for long-term storage. This occurs when you link information to your existing knowledge, or process it.

This is a very serious limitation of the MSM because it is another research finding that cannot be explained by the model.

Another weakness is that it relies in rehearsal for information to be transferred to LTM, but some strong emotional memories seem to bypass STM and are recalled vividly from LTM without rehearsal. Also MSM focuses on the stores of the memory and not the processes involved. It implies that memory is a passive process, not active, and does not take into account the different strategies that people use to remember things. Nor does it take into account why some things are easier to recall than others.

Question 17

Why is research studies supporting the MSM using artificial materials a weakness?

Answer 17

Researchers often asked participants to recall digits, letters and sometimes words. Peterson and Peterson (1959) even used consonant syllables which have no meaning.

In everyday life we form memories related to all sorts of useful things - people’s faces, their names, facts, places, etc.

This suggests that MSM lacks external validity. Research findings may reflect how memory works with meaningless material in lab testing, but does not reflect how memory mainly works in everyday life.

Question 18

How does the MSM oversimplify the long-term memory store?

Answer 18

There is a lot of research evidence that LTM is not a unitary store.

We have one LTM store for memories of facts about the world (semantic), a different one for memories (episodic), and a different one for skills and actions (procedural).

The MSM is limited because it does not reflect these different types of LTM.

Question 19

Who was Murdock?

Answer 19

One study that supports the multi-store model was carried out by Murdock (1962) who had conducted an experiment known as the ‘serial position effect’. He found that words first and last in the list were recalled correctly. He claims that this was due to the ‘primacy’ and ‘recency’ effect.

The primacy effect is where information processed earlier is constantly being rehearsed, which results in the information being encoded into the long-term memory. The recency effect is where the last bit of information processes into your memory is still freshly encoded in your short-term memory, due to the 18-30 second duration rate, thus is easily recalled. However, the task in this experiment lacks ecological validity.