Memory can be divided into three main stores: sensory memory, short-term memory, and long-term memory. Key research has found differences in how information is coded, the duration it can be stored, and storage capacity across these three memory stores. Sensory memory stores information in its raw form for milliseconds. Short-term memory codes information acoustically and can store around 5-9 bits for up to 30 seconds. Long-term memory semantically codes information for retrieval over a lifetime. While this multi-store model is supported by research, it is an oversimplification as memory is more complex with multiple processes involved.

1. Memory

2. Memory
Memory stores are different in terms of:
Coding
Capacity
Duration

3. Memory: sensory memory
• Coding: information is stored in sensory
memory stores in an unprocessed form in it’s
original form or modality: raw code.
• Duration: information is stored in sensory
memory for a very short duration: milliseconds.
• Capacity: a lot of information can be stored in
sensory memory.

4. Memory: short-term memory
• Coding: information is stored in short-term
memory in an acoustic code.
• Duration: information is stored in short-term
memory for a very short duration: up to 30
seconds.
• Capacity: not much information can be stored
in short-term memory: between 5 and 9 ‘bits’
or ‘bytes’ of information.

5. Memory: Long-term memory
• Coding: information is stored in long-term
memory in a semantic code.
• Duration: information is stored in long-term
memory for a very long time: up to a lifetime.
• Capacity: a huge amount of information can be
stored in long-term memory.

6. Memory
• You need to know some key research
that has found differences in the
coding, duration, and capacity of
sensory memory, short-term memory,
and long-term memory.

7. Sensory Memory: duration
 Sperling (1960)
 Used a tachistoscope to present participants with a
grid of 12 letters.
 Asked participants to write letters down
 Now you try
 You will have 1s, Sperling’s participants had 50 ms!

9. Sensory memory: duration
• Try again.
• The grid of 12 letters will be presented for 1
second.
• Write down as many of the letters you can
remember.

11. How many letters did you remember?
 Participants reported the image fading.
 Sperling called this fading memory: Iconic Memory
 The duration of information in sensory memory is
milliseconds.

12. Short-term memory: duration
 Petersen and Petersen (1959)
 Presented participants with a three letter
trigram: CPW.
 Rehearsal was prevented by getting
participants to count backwards in 3’s.
 After 3, 6, 9, 12, 15, and 18 seconds the
participants had to recall the trigram.
 After 18 seconds less than 10% of participants
could recall the trigram
 Information lasts between 18 to 30 seconds in
STM.

13. Long-term memory: duration
 Bahrick et al (1975)
 392 high school graduates
shown photographs from
their school yearbook.
 Participants had to name the
photographs.
 One group had to match a
name to the photograph.
 A second group had to name
the photograph without help.

14. Long-term memory: duration
 After 47 years participants in the name matching
condition accurately identified the name of the
person in the photo 60% of the time.
 This provided evidence that information could be
stored in LTM for a very long time.

15. Coding in STM & LTM
• Baddeley et al (1966)
• Baddeley carried out research to find
what code information was stored in
SM and LTM.
• Read the textbook extract ‘Key study:
encoding in STM and LTM’.

16. Coding in STM and LTM
• Baddeley (1966) concluded:
• STM stores information in an acoustic
code.
• LTM stores information in a semantic
code.

17. Multi-store model: evaluation
• Research backs up the multi-store model
that there are separate memory stores.
• Research backs up the multi-store model
that information is stored differently in
terms of coding, duration and capacity in
each memory store.

18. Multi-store model: evaluation
• Evidence from case studies of brain damaged
people with amnesia supports the distinction
between STM and LTM.
• Clive Wearing provided evidence that STM and
LTM are separate memory stores.
• H.M. provided evidence that STM and LTM are
separate memory stores.

19. Multi-store model: evaluation
• Problems have been identified with
the multi-store model.
• It is too simple.

20. Multi-store model: evaluation
• There is evidence that STM is more complex than a
single store that encodes information in an
acoustic code.
• There is evidence that there is more than one
unitary STM memory store:
• A visual memory store
• An auditory or acoustic memory store

21. Multi-store model: evaluation
• There is evidence that LTM is more complex
than one unitary LTM memory store.

22. Multi-store model: evaluation
• The multi-store model focuses on the structure of
memory and neglects the processes involved in
memory.
• It only identifies rehearsal as the main way
information is processed for storage in STM and
LTM.
• Research has identified that many more processes
are involved in memory.

23. Multi-store model: evaluation
• Most of the research that backs up the multi-
store model of memory is based on lab research
using artificial tasks that most people find
meaningless.
• This research may not tell us much about what
people use their memory for in real life situations.