From the Latin word for sudden. The instant recognition that there are 1, 2, 3, and sometimes 4 objects before you, without counting (some references put the limit at 7 or 8).

I have been known to say that the reason things come in threes is because two is too few and four is too many. I find this to be particularly true when I'm writing. The pattern "... A, B and C." is much more satisfying than either "... A and B." or "... A, B, C and D." in almost all cases. A list of things with only two elements isn't very interesting; a list of four things often seems strained; but, a list of three things usually feels just right (note that this sentence has three qualifications).

But, subitization provides an explanation. Three is the greatest safe number for subitization (since determining that a collection has four elements more often requires counting), so it makes a natural choice of length for lists that pack the most material without giving the reader a feeling of being overloaded.

More information at Xrefer.

No comments: