L1-4 Memory Flashcards
What is short term memory
Short term memory stores and follows recall of info for a short period of several seconds up to 30 seconds without rehearsal. It has a very limited capacity
Duration
Does not last long
Requires rehearsal to keep info in our STM for more than a few secs and keep it active
Case study to support was Peterson and Peterson (1959)
- 24 undergraduate students presented with consonant trigram (3 random consonants)
- they were then asked to count backwards in threes to stop them rehearsing the trigram
- after intervals of 3,6,9,12,15 or 18 seconds pps had to stop counting and repeat the trigram
- this was repeated using different trigrams
Results = pps could remember abt 90% of trigrams after 3 seconds, 20% after 9 seconds and less than 10% when there was an 18 sec interval
Information decays very quickly when you cant rehearse it
Max STM duration is abt 18 seconds
Capacity
Measured by Jacobs (1887)
Developed the serial span technique. The researcher read out 4 digits and the pp was asked to repeat it back immediately. More digits were then added until the pp could not accurately repeat back the digit string
On average 9 digits 7 letters correctly recalled
Capacity increased w age during childhood, gradual increase in brain capacity, people develop strategies to improve digit span such as chunking.
Digits also easier to recall and remember because there are only 10 compared to 26 letters
Miller 7+/-2
Miller (1956) reviewed experiments into capacity of short term memory and concluded that it has a capacity of 7+-2
He also said that memory capacity can be increased through a process called chunking. Miller found for example that people could remember 5 letters as well as they could remember 5 words
