# Simon (1974): The Limits of Chunking

Simon (1974) carried out a span experiment in which the size of the chunks of information was varied. Use the information from the table below to plot a graph of Simon's (1974) results. Click 'add point' to create a new point on the graph, then drag it to the right position using the mouse. Repeat this until you have plotted all the data, then click 'draw graph'. If you are happy with the result, click 'finished'. If not, click 'reset'.

| size of chunk
--- | ---
| 1 word | 2 words | 3 words | 4 words
number recalled | 7 | 4 | 2 | 1

As the graph shows, the number of chunks accurately recalled declines sharply as the size of the chunks increases. The PPs can recall seven one-word chunks, as Miller (1957) suggested. However, if the chunks consist of four words, PPs can (on average) recall only one. This is contrary to Miller's original conclusion.

This shows that, even though chunking allows people to store more information at one time, STM capacity still has an overall limit, .