The urban legend that is Seven, Plus or minus two

The legend goes that in 1956 George A. Miller wrote a research paper showing that people can remember from five to nine (Seven plus or minus two) things. This research has led to modern day designers creating menus / tabs that contained five to nine items on the screen. Well, this theory is not really accurate.

In 1994 psychologist Alan Baddeley questioned George A. Miller’s seven plus or minus two rule and discovered that the idea came from a talk that Miller gave at a professional meeting. And it was basically Miller thinking out loud about whether there is some kind of inherent limit to the amount of information that people can process.

The real magic number is actually four. Baddelley and Nelson Cowan both conducted a long series of studies on human memory and information processing, what they discovered was that people can hold three or four things in working memory as long as they aren’t distracted or interfered with. What the research also showed was that people employed “Chunking” to help with memory retention. A good example of this is phone numbers, it’s no accident that phone numbers look like this 0414 XXX XXX / 02 9978 8888. Instead of having to remember 10 separate numerals a phone number has three chunks, with four or less items in each chunk.

Further readings

Below is a video showing a Chimp vs Human in a working memory test