# What type of learning mechanism produces a consistent typo?

There is a typographical error that I make and do so every time I try to type a certain word. Whenever I try to type remember, I type remeber. I do this every time. This is different to a regular typo because most typos happen at random, whereas this mistake is guaranteed to occur. It's not a spelling mistake, because I know how to spell remember, I just don't press all the required keys.

Could it be related to touch-typing? I don't make the typo when I peck out the keys.

I wonder whether it is related to muscle memory, because there are many words with the pattern 'e_e', such as here, there, gene, theme, scene, etc. So where I reach the second e my motor system is primed not to push the key that came before, i.e. m.

It seems that knowledge of spelling and knowledge of typing are not strongly linked in this case.

Is there a mechanism by which I have learnt this mistake?

-

There is a scientific literature on typing. It's been a while since I've read the articles. You might start by reading this excellent review of research and findings on transcription typing.

### General model of typing

Salthouse (1986) presents a model of the typing process

1. INPUT: Convert text into chunks
2. PARSING: Decompose chunks into ordinal strings of characters
3. TRANSLATION: Convert characters into movement specifications
4. EXECUTION: Implement movement in balistic fashion


A few other relevant points that Salthouse supports with multiple references:

• "The rate of typing is nearly the same for random words as it is for meaningful text."
• "Successive keystrokes from fingers on alternate hands are faster than successive keystrokes from fingers on the same hand."
• "Letter pairs that occur more frequently in normal language are typed faster than less frequent pairs."
• Interkey interval varies with the context of the letters in a word.

These points basically state that typing involves various forms of motor chunking, that the word is a central chunk but that there are also many other lower level chunks (e.g., typing "ion" and "ier" is quite common in English).

### Errors

There's also a discussion of typing errors in the paper.

• 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"

I suggest you have a read of the paper to get a deeper understanding of the types and proposed causes of typing errors.

### Specific thoughts regarding your question

• Perhaps in contrast to what you say, typos are not random. Rather, there is structure to the errors. For example, "Teh" is a common typo.
• Obviously, having an incorrect belief about the spelling of a word could result in repeated errors, but I understand you are not talking about them.
• So, with regards to a specific word that you frequently mistype, you might want to think whether there are characteristics of the word that make it difficult to type. Also, as you say, if you learn the wrong chunking at some point, you may need to unlearn this pattern.

### References:

• Wells, F. L. (1916). On the psychomolor mechanisms of typewriting. American Journal of Psychology, 27, 47-70.
-
"The rate of typing is nearly the same for random words as it is for meaningful text.", as a touch typist I would be surprised by that. :O Some common sequences flow out of your fingers while others are noticeably slower, but I could just be imagining stuff and I could just be noticing "Letter pairs that occur more frequently in normal language are typed faster than less frequent pairs.". –  Steven Jeuris Jan 22 '12 at 12:35
"Teh" is not always a typo. ;p –  Steven Jeuris Jan 22 '12 at 12:40
@StevenJeuris just to be clear, I think the point is that at least in transcription typing, random letters are much harder to type, but random words (e.g., typing "what happy cat doing is red") are not that much harder to type. –  Jeromy Anglim Jan 23 '12 at 2:11