# Digit Span Evidence: Summary

You have now completed the module on research into digit span. The most important ideas about digit span research are:

- Miller (1957) discovered that STM seems to have a fixed capacity of 7 plus or minus 2 digits.
- Miller also discovered that chunking increases the capacity of STM.
- Simon (1974) found that STM capacity depends on the size of the chunks of information used. A person can store up to seven small chunks of information, but only two or three larger chunks.
- Therefore, whilst STM capacity is larger than the seven digits suggested by Miller's research, it does have an overall limit.

## Where Next?

Topic | Level | What's this? |
--- | --- | --- | ---
Recency Effects | Basic | Find out about a different way of measuring STM capacity |
Evaluating Digit Span Evidence | Advanced | Explore some criticisms of experimental research using digit span measures |