Factors that affect the capacity of STM

It is not easy to demonstrate the exact capacity of STM because it will vary depending on the nature of the material to be remembered and on certain other factors. The capacity of computer storage systems or memory sticks can be accurately gauged because information is loaded into them in the form of basic units (eg: the capacity of a memory stick might be 1GB or a million 'bits' of information). There is, as yet, no way of defining a basic unit of information to be stored in human STM. It is also possible that STM is not the unitary store described by Atkinson and Shiffrin. In that case, the task of defining the capacity of STM becomes even more difficult.

There are a number of factors that appear to affect the capacity of STM.

• Influence of long-term memory: Cohen (2000) believes that Miller might have overestimated the number of chunks that can be held in the STM. He thinks that performance on span tasks is…