George Miller The Magic Number Seven plus or minus two!!

Miller was intrigued as to why the number 7 kept appearing everywhere. For example, the seven wonders of the world, seven deadly sins, seven primary colours, seven notes of the musical scale, seven days of the week and so on.

In this article Miller reviewed findings from previous studies:

• Participants can easily distinguish between 3 musical tones but when over 5 tones are presented, confusions are more frequent.

• When an array of dots are flashed on a screen, patterns containing 5 or 6 dots can be counted easily; more than that results in less accurate counts. This demonstrates the span of immediate (or short-term) memory.

• If memory is limited by the 'bits' of information it can handle, we should be able to remember half as many 10-letter words as 5-letter ones. In fact this is not true. We can remember about 7 words no matter how many bits of information (phonemes or sounds) are in the word. It is 'chunks' of data which limit memory rather than information.

Miller concluded that seven chunks of data is about the maximum amount of information we can process at any one time.

You can read Miller's article in full at http://psychclassics.yorku.ca/Miller/

Note on methodology

Notice how Miller's article is not a study in the sense that he conducted a practical (or empirical) investigation. Instead he summarised a number of research investigations (as well as everyday observations), trying to make sense of their findings.

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