Why do many television ads list a phone number like 1-800 CALL ATT instead of as 1-800 225 5288? After all it’s easier to use the numbers on the touch pad instead of hunting up the letters. Relate this to short-term memory.

What will be an ideal response?

The number of chunks one has to remember is smaller when the phone number is given in terms of words instead of numbers. The purely numeric version of the phone number has 8 chunks (the 1-800 plus the 7 digits) which is pushing on the upper edge of what Miller says is the limits of short term memory. On the other hand, the 1-800 CALL ATT version of the number only has three chunks.