I tend to make almost no spelling errors in the things I write. Still, I regularly use a spell checker just to make sure nothing is spelled wrong. Upon inspection of a draft (the spell checker did not have its way with the text yet) for a writeup, I recently discovered that I had made two mistakes. Both of these errors would slip by a spell checker, because the misspelled words had become other words. These two typos were:
- "is Switzerland" instead of "in Switzerland"
- "making my angry" instead of "making me angry"
I made no other mistakes but these.
Pondering this strange coincidence I came to the conclusion that I must have learned not to make any spelling errors that would be detected by a spell checker. But since my attention has never been called to the errors that are not detected by a spell checker, I have never learned to avoid doing these.
And though I always read the stuff I write to look for mistakes, it is easy not to notice such small errors as the ones described above. Your mind usually automatically compensates for such little mistakes. It is easier to find the mistakes in more complicated words, because you pay attention to them. It was only by chance that I read the text more thoroughly than usual.
In conclusion, I think it is most probable that survival of the fittest also applies to typos. The ones that get noticed are corrected while the ones that (almost) never get noticed survive. I suppose it's that way with everybody's typos. | 
