Short and Long-term Memory Flashcards
Define coding (encoding).
The way information is changed so that it can be stored in memory.
Enters through senses, stored as visual codes (pictures), acoustic codes (sounds) or semantic codes (meaning of experience).
Define duration.
A measure of how long a memory lasts before it is no longer available.
Define Long-term memory (LTM).
Your memory for events that have happened in the past
What is the duration, capacity and coding of LTM?
Can last anywhere from 2 minutes to 100 years - unlimited
Unlimited capacity
Tends to be coded semantically
Define short-term memory.
Your memory for immediate events.
Measured in seconds and minutes rather than hours and days.
What is the duration, capacity and coding of the STM?
Short duration (unless rehearsed)
Limited capacity of about 4 items or chunks
Tends to be coded semantically
Define capacity.
This is the measure of how much can be held in memory.
Represented in terms of bits of information, e.g. number of digits
What experiment tests the duration of the STM?
Peterson and Peterson
Trigram Experiment
What were the aims of the Peterson and Peterson trigram experiment?
Information held in the STM appears within about 20 seconds if rehearsal is prevented
What was the procedure of the Peterson and Peterson Trigram Experiment?
- 24 students in a lab
- researcher called out 3 letters followed by 3 numbers
- students counted down in thread from number read out
- after a certain period of time (3,6,9,12,15 or 18 seconds) researcher says stop
- students have to say the 3 letters they started with
- researcher wrote down their response
What were the findings of the Peterson and Peterson trigram experiment?
90% of trigrams were recalled after 3 seconds
50% of trigrams were recalled after 6 seconds
Less than 10% recalled after 18 seconds
What were the conclusions of the Peterson and Peterson trigram experiment?
Duration of the short term memory is that 18 seconds
Information was often lost in short term memory unless it can be solidated
Criticisms of Peterson and Peterson trigram experiment
The experiment was only done up to 18 seconds and not above 20 - said that in hypothesis
Only done on 24 students - no range
Not life like- isn’t how you use STM - generalisation
What experiment tests the duration of the LTM?
Harry Bahrick et al
1975
What were the aims of Harry Bahricks experiment?
Wanted to see the duration of the long-term memory