The multi-memory store

The Multi-Store Model (Atkinson and Shiffrin, 1968)

Atkinson and Shiffrin suggests that there are three stores of memory:

• Sensory
• Short-term
• Long-Term

Information is detected from the sense organs (sight, smell) and then goes into the sensory memory.

If attended to it would then go into the Short-Term Memory (STM)

Information is then transferred from the STM to the Long-Term Memory if rehearsed

When rehearsal doesn't occur it can be displaced or decay happens in the STM-the information is forgotton

Each store differs in its: Capacity, duration and encoding

Capacity:

Miller (1956):  

Procedure: The experiment "Millers Magic Numbers" saw participants being subjected to a number of auditory tones varying in pitch. They were asked to recall the tones but after 5-6 they began to get confused, their ability to recall anything else broke down.

Conclusion: Short-Term memory can hold 7 +/- 2 items. He also said the same for individual letters and digits. Information can also be chunked -we remember more letters if they are in words.

Baddley (1975):

Stated that the capacity of STM was roughly what could be reheared in 2 secounds

Criticism: works for words but not faces, music and pictures

Duration:

Peterson and Peterson (1959):

• A participant is presented with a set of 3 numbers
• Asked to count backwards in 3's from 100
• They were asked to recall the numbers every 3 seconds up to 18 

Results:

After 3 seconds, recall was 80% correct, but after 18 seconds, recall was only 10% correct.

Conclusion:

Information can be lost quickly if it's not rehearsed

Baddeley (1966):

Procedure:

4 groups were allocated 4 conditions of words: acoustically similar (sounds the same), acoustically dissimilar, semantically similar (same meaning)  and semantically dissimilar    

They were then presented with 5 words from their category and asked to recall the list correctly immediately after.

Results:

Acoustically similar words was the hardest to recall with only 55% accuracy whilst semantically similar words was easier to remember.

Conclusion:

 Sound is important to short term memory encoding. However, this can't be the only way we encode. What about faces? He also concluded that the Long-Term memory mainly uses semantic encoding.

Criticism: low eco validity (people don't recall lists in everyday life) and these are not the only ways we encode

Capacity and duration:

Limitless capacity and duration (difficult to test)

Study to test capacity:

Procedure-

• 400 participants were put through 3 tests (visual, verbal and free recall)
• 50 pictures were put up and the graduates and to recall their ex friends
• A name recogision test
• Free recall

Findings:

• 15 years after graduation, participants were 90% accurate in recalling names and faces
• 48 years later they were 80% accurate in recalling names and faces