I know the difference between "its" and "it's". When I read it, even in my own writing, I can see incorrect usages almost instantly. However, when I type, I often type "it's" when I should write "its." The opposite problem is rare ("its" when it should be "it's"). I don't even notice that I've written it incorrectly unless I proof-read my writing.

So, why do I do this?

I've looked at these questions and answers:

Why do you sometimes write down one word while actually intending to write another?

What type of learning mechanism produces a consistent typo?

But neither really seem to address this case. The first accepted answer refers to speech errors and centers around sounds and phonemes. Since there isn't anything phonetically different between "it's" and "its" I can't see how I have stumbled into this problem:

When mentally planning the next word in a sentence, we must choose the appropriate lemma. By selecting the units in a neural network that correspond to a certain lemma, it spreads activation to the corresponding morphemes, which in turn spreads activation to its corresponding phonemes. When the activation of a phoneme unit exceeds a certain threshold, it is selected for utterance (e.g., spreads activation to the motor units that allow us to speak).

The second answer refers specifically to mechanical typing errors arising from looking at text (which I am not doing) and striking the wrong key. These errors don't seem to cover my situation:

  • Salthouse mentions the taxonomy of typing errors proposed by Wells (1916) of "substitutions, intrusions, ommissions, and transpositions", and also cites empirical estimates of prevalence of
    different types of errors.
  • "Many substitution errors involve adjacent keys."
  • "Most transposition errors are cross-hand rather than within-hand"

My problem is adding unnecessary punctuation and not a mechanical error or phonetic/psycholinguistic error. Am I wrong?

  • $\begingroup$ The first answer states "The same model can predict typographic errors as well". However, I just reread that answer and I can confirm, indeed I do not make the speech error of saying "possible" instead of "possibly", although I do type it wrong sometimes. The answer there not answering your question does not prevent this from being a duplicate question. You can comment on the question/answers there to raise shortcomings so possibly new answers can be added. I will already start by unaccepting the current answer. $\endgroup$ – Steven Jeuris Sep 12 '13 at 21:39
  • $\begingroup$ I particularly believe Mien's answer to be a more plausible answer now. Would be worthwhile investigating more into. Similar to Jeff's explanation, but then applied to muscle memory. $\endgroup$ – Steven Jeuris Sep 12 '13 at 22:01
  • $\begingroup$ @Steven Just my opinion, but I wonder whether this question is a duplicate. I guess it is an instance where a general question has been asked, but here we have a more specific question. The specific question comes under the umbrella of the broader question, but I also think that the more specific question will get a more specific answer. I'd be happy to add an answer to this question. $\endgroup$ – Jeromy Anglim Sep 12 '13 at 23:51
  • $\begingroup$ @JeromyAnglim By all means, if you think your answer here doesn't answer my question which I thought was a duplicate, reopen and answer it! $\endgroup$ – Steven Jeuris Sep 13 '13 at 8:03
  • $\begingroup$ ANSWER: Most likely the 2nd because hitting ' by accident seems implausible in the context of typing "its". The general name for this class of spelling errors is "phonologically plausible errors" (PPEs). The question that was linked as duplicate of this contains mostly irrelevant information focusing on speech rather than spelling errors... and doesn't even mention PPEs. $\endgroup$ – SX welcomes ageist gossip Apr 3 '19 at 12:25