AM  Vol.5 No.10 , June 2014
Probability Theory Predicts That Chunking into Groups of Three or Four Items Increases the Short-Term Memory Capacity
Author(s) Motohisa Osaka
ABSTRACT

Short-term memory allows individuals to recall stimuli, such as numbers or words, for several seconds to several minutes without rehearsal. Although the capacity of short-term memory is considered to be 7 &#177 2 items, this can be increased through a process called chunking. For example, in Japan, 11-digit cellular phone numbers and 10-digit toll free numbers are chunked into three groups of three or four digits: 090-XXXX-XXXX and 0120-XXX-XXX, respectively. We use probability theory to predict that the most effective chunking involves groups of three or four items, such as in phone numbers. However, a 16-digit credit card number exceeds the capacity of short-term memory, even when chunked into groups of four digits, such as XXXX-XXXX-XXXX-XXXX. Based on these data, 16-digit credit card numbers should be sufficient for security purposes.


Cite this paper
Osaka, M. (2014) Probability Theory Predicts That Chunking into Groups of Three or Four Items Increases the Short-Term Memory Capacity. Applied Mathematics, 5, 1474-1484. doi: 10.4236/am.2014.510140.
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