7 plus or minus 2

You may have heard about the 7 plus or minus two rule. Psychology tells us that you can only store between 5 and 9 chunks of information in your short term memory at a time. A chunk, however, can consists of several pieces of related data. Consider your phone number. It has a country code, area code, and then one or two more sets of numbers. Although this can be over 14 numbers long, it is usually grouped into several chunks and therefore falls well into our short memory range.