Why the Credit Card Number is Divided into Groups?

I always knew my credit card number is grouping as 4 digits per group but never thought about why. Today I had an interesting reading about short-term memory. Research has been done showing that short-term memory capacity is a function of chunks rather than the objective number of items. That being said, if you try to remember a string of numbers or digits, divide them into small groups could improve the recall performance. Specifically, Wickelgren (1964) showed that a string of digits are easiest to remember if they are divided into groups of a maximum of four. That’s one of the underlying reasons why we have credit card numbers being organized in groups. Though each part does present different information, but its presentation in groups is also an important strategy to make it easier for customers to check and remember. Similarly, when we design the presentation of information, make sure not offering too much at a time. Instead, group them to make it simple for users to recall.

Wickelgren, W.A. 1964. Size of rehearsal group in short-term memory. Journal of Experimental Psychology, 68, 413-419.


4 thoughts on “Why the Credit Card Number is Divided into Groups?

  1. wjciv

    I’ve seen a similar memory thing with relation to letter groups. For instance, remembering 9 letters is fairly hard in the span of 2 seconds. But if those letters are NBA FBI VCR, it is relatively easy for most Americans because we split it into 3 units instead of 3 3 letter groups.

    Which made me think when my credit card number was read back to me earlier today as pairings of 2 digit numbers (5048 became fifty, forty-eight). Could we remember more things if we remembers bigger numbers instead of restricting ourselves to the digits?

    1. Emma (Zhihua) Post author

      Hi William, thank you for your interesting thoughts!! You are absolutely right. Both your examples illustrate the principle that people are good at remember “chunks” of information rather than a string of information without chunks. This could be applied to both letters and numbers. One experiment has been done in 1979 to address exactly the same question of your second example. And they verified that chunking took up less short-term memory capacity.


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