Capacity

• Storage - the retention of knowledge. When we research how much information can be stored this is capacity
• Capacity/storage - the capacity of the STM is limited. The LTM is unlimited
• Jacobs 1887 (capacity) - testing the capacity of the STM. Ppts has to repeat a string of numbers or letters in the same order. The number of items gradually increases until ppts could no longer recall the sequence.

  Average span of 7.3 letters and 9.3 numbers.
• Miller 1956 (capacity) - everyday observations, things come in groups/chunks e.g. 7 notes on musical scale, 7 days of the week

  Proposed that the span (capacity) of STM is around 7 items but it can be improved by chunking
• Capacity AO3. The capacity of the STM may be even more limited.

  Cowan reviewed many studies on the STM and found that it may be limited to 4 chunks, not 7.

  This suggests that the STM may not be as extensive as we thought. Research on capacity of STM for visual info also found 4 items is the limit
• Capacity AO3. The size of the chunk is also relevant.

  Simon said that capacity can be increased if info is separated into smaller bits. He tested his own immediate digit span and found larger chunks harder to remember. However this may be biased as he was his own subject.
• Capacity AO3. There are individual differences. Capacity of the STM is not the same for everyone. Jacobs found that recall ability increased steadily with age. This may be due to gradual increase in brain capacity.