Short and long-term memory

CAPACITY

• AO1 STM: Jacob digit span technique showed that the avergae soan for digits was 9.3 items, and 7.3 items for letters. This is because there are only nine numbers, but 26 letters.
• AO1 Immediate memory: Miller magic number seven plus or minus two. The span for immediate memory is 7 items - sometimes more, sometimes less. People count count 7 dots when flashed onto a screen, and the same goes for musical notes, letters and even words. People can recall five words, as well as five letters as we chunk things together to remember them more.
• AO3 Cowan reviewed studies - STM capacity is limited to four chunks. Vogal found that for visual info four items was the limit. Thus, the lower end of Miller's range is appropriate.
• AO3 Size of the chunk also matters. Simon - people had a shorter memory span for larger chunks like eight letter words as opposed to smaller chunks like one-syllable words.
• AO3 Individual differences. Jacobs found that recall/digit span increased with age. Those 8 years old = 6.6 digits, yet those 19 years old  = 8.6 digits. This could be due to increased capacity or because people develop strategies to remember things better…