Memory

Memory

Memory stores are different in terms of:

Coding

Capacity

Duration

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.

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.

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.

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.

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!

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.

How many letters did you remember?

Participants reported the image fading. Sperling called this fading memory: Iconic

MemoryThe duration of information in sensory

memory is milliseconds.

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 trigramInformation lasts between 18 to 30

seconds in STM.

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.

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.

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’.

Coding in STM and LTM

• Baddeley (1966) concluded:

• STM stores information in an acoustic code.

• LTM stores information in a semantic code.

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.

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.

Multi-store model: evaluation

• Problems have been identified with the multi-store model.

• It is too simple.

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

Multi-store model: evaluation

• There is evidence that LTM is more complex than one unitary LTM memory store.

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.

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.