In order to understand the models of memory you will need to know what is meant by the following terms:
Term Definition
Encoding Coding information so it can be stored in your memory, it makes words have meanings.
Storage This happens as a result of encoding.
Retrieval Recovering stored information from the memory system.
Capacity The amount of information (usually pieces) a memory store can hold.
Duration The amount of time information remains in a memory store.
Rehearsal Repeating information over and over again mentally.
Acoustic How information sounds if it is spoken/ thought aloud.
Semantic Information with meaning.
  • Atkinson and Shiffrin’s Multi-Store model comprises of three different memory stores: sensory memory, short term memory (STM) and long term memory (LTM).
  • The process of memory is as follows:
  • Information enters the sensory memory and if attention is paid to the information it is passed on to short term memory, if it is not paid attention the information will be lost as trace decay.
  • Once in short term memory, information is either transferred into long term memory by rehearsal or is lost by trace decay.

The following table summarises the model including duration, capacity and encoding of the stores and gives research about the different stores of memory.
Short Term Memory Long Term Memory
Duration 18 seconds 48 years +
Research: Peterson & Peterson

Participants were presented with a trigram (eg- LDI, CTG) which they then had to recall after a delay of 3, 6, 9, 12, 15 or 18 seconds. During the delay rehearsal was prevented by participants counting down from a random number in threes.


3 second delay = 80% success.

6 second delay = 50% success.

18 second delay = less than 10% success.

Research: Bahrick

Ex-high school pupils were asked to:

a) Freely recall as many names of people they went to school with as possible.

b) Identify people who they went to school with from photographs.


After 34 years of leaving high school there was 90% accuracy in both conditions and after 48 years of leaving high school this decreased to 80% accuracy for free recall and 40% accuracy for face recognition.

Capacity 7±2 pieces of information Infinite
Research: Miller/ Jacobs

Participants were presented with a sequence of letters or digits containing three items which they had to recall. This then increased by one item each time until they could no longer recall the sequence.


Average number of items recalled was between five and nine.

Encoding Acoustic Semantic
Research: Baddeley

Four groups of participants heard a list of words repeated four times before being given a list with all the words they had just heard on and being asked to put them in the correct order. The conditions were: acoustically similar words (cat, mat, hat), acoustically dissimilar words (pit, day, cow), semantically similar words (big, huge, tall) and semantically dissimilar words (hot, safe, foul).


Rearrangement of the acoustically similar words was done least successfully when recalling from short term memory and rearrangement of the semantically similar words was done least successfully when recalling from long term memory.


  • Strength- Research for short term memory supports that there is two stores.
  • Strength- Primacy (remembering the first words in a list as they are transferred to LTM) and Recency (remembering the last words in a list as they are still in STM) effect shows that there are two stores.
  • Strength- The case studies of HM + Wearing prove there are two stores.

File:Henry Gustav 1.jpg


  • Weakness- Research lacks mundane realism.
  • Weakness- Not everything that goes into long term memory is rehearsed.
  • Weakness- Naive and Simplistic- description rather than explanation.