Probability Theory Predicts That Chunking into Groups of Three or Four Items Increases the Short-Term Memory Capacity ()
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 ± 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.
Share and Cite:
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.