Slides in this set
The Atkinson & Shiffrin Model
(The Multi-Store Model)
The multi-store model proposes that memory consists of 3 stores: Sensory Store, Short-term store
and a Long-term store.
· Information from our environment (visual and auditory) goes into our sensory memory.
· If you pay attention to this information, the information will be encoded and will pass into short-term memory.
· If this information is processed further through rehearsal, it will be transferred to the long term memory.
There are 4 main ways in which STM and LTM differ.
1. Encoding- The process of breaking down information into a form our brain understands.
STM mainly encodes acoustically, LTM encodes semantically.
1. Capacity- How many items the store can hold.
STM has a limited capacity of 7+-2 items, LTM unlimited capacity.
1. Duration-How long the information lasts until it decays from the store.
STM very limited duration of 15-30 seconds, LTM infinite duration.
1. Forgetting- When memorys/information decays and is lost from the brain.…read more
Information is stored in the Iconic(Visual information), Echoic(Acoustic Information) and Haptic
(Tactile information) stores.
Sperling 1960- Evidence for Sensory Memory
Sperlings aim was to provide evidence for sensory memory using a Whole- Report Technique.
1. Showed participants a 4 by 3 row of letters for 50 milliseconds.
2. Participants were told to recall them.
He found that participants remembered 4-5 letters and concluded that information remains in the sensory memory
for a brief period of time (1.2 seconds) He also found that information is passively registered meaning that the
participents were aware of there being more letters but they could not recall them.
· High levels of control due to Lab Experiment and it can be replicated with similar results (reliable)
· The Stimuli used were artificial and may not reflect how we use memory in everyday life (lacks validity)
· Participants may have felt frustrated when they could not recall the letters so debriefing was important to
reassure peoplet that their performance was within the normal range.…read more
Capacity of STM:
Jacobs studied the Capacity of STM by aiming to demonstrate how much information could be stored. He presented
participants with a string or letters/digits and they had to repeat them back in the same order. The number of digits
increased until they failed to recall the sequence correctly.
· Participants recalled about 9 digits and 7 letters.
· He concluded that the digit span increased with age and that the STM has a capacity of 5-9 items depending on
the material used!
Although, Jacob's research is artificial and lacks ecological validity. More meaningful information would be recalled
better which would show STM to have an even greater capacity. Situation variables were also controlled so there
were no distractions which could cause the results to be unrealistic.
Factors affecting the capacity of STM:
PIRI piri chicken. Pronounciation time, Influence of LTM, Reading aloud & Individual Differences. (You only have to
know one of these in detail.
Reading Aloud causes the digit span to increase instead of reading sub vocally due to digits being stored in the
echoic store which would strengthen the memory trace.…read more
Duration of STM:
Peterson & Peterson aimed to provide evidence for STM duration when verbal rehearsal is
-24 university students were presented with nonsense TRIGRAMS followed by a 3 digit number.
- Participants were giving a INTERFERENCE TASK of counting backwards in 3's to prevent rehearsal.
-They were asked to recall the trigrams after intervals of 3,6,9,12,15 or 18 seconds.
They found that after 3 seconds, 90% recall and after 18 seconds, only about 10% recalled correctly. This shows
that when rehearsal is prevented, very little can stay in the STM for longer than 18 seconds.
These results would be reliable as it was a lab experiment however nonsense trigrams are artificial so the study
lacks ecological validity. Only one type of stimulus was used- the duration of STM may depend on the type of
Factors effecting STM duration:
The IRA, Intention to recall, Rehearsal & Amount of information to recall (only need to know one in detail)
Intention to recall- it makes a difference whether we make an effort to recall material or not.…read more
STM & LTM Encoding
Encoding is the way in which information is represented in the memory store i.e in the STM information is mainly
Baddeley (1966) investigated encoding in STM & LTM
· Baddeley aimed to provide evidence for a distinction between STM and LTM in terms of encoding.
· He presented participants with four sets of words that were either acoustically similar (e.g man, mad, mat),
acoustically dissimilar (e.g pit, cow, bar), semantically similar (e.g big, large, huge) and semantically dissimilar
(e.g good, hot, pig).
· Used an independent groups design.
· Participants were asked to recall the words either immediately or after a 20 minute task.
When tested immediately they mainly made acoustic errors (STM) and when tested after 20 minutes they made
mainly semantic errors (LTM).
This shows that STM and LTM are two separate stores which favour different methods of encoding. STM is more
likely to rely on acoustic encoding and LTM relies on semantic encoding.
- Lacks ecological validity.
- There are other types of LTM such as episodic memory and procedural memory and other methods of encoding…read more