I have been typing "untamed" a long time. With some very few exceptions, I am a four-finger typist.
The left Pinky is planted above the left Shift key (ISO, far left) and the left Ring finger is almost always over the letter 'A' when not used for Control (Caps Lock).
I think that my brain translates words into typing by breaking down the words into smaller combinations that can be typed faster. At the lowest level, these combinations are bigrams. I have noticed that I tend to type bigrams with keys next to each in fast combinations of an Index and Middle finger on the same hand. Then there are lots of bigrams with 'A'. (left Ring and Index finger). The most common of these for the English language must be {ER} and {RT}.
Example. The word "OPERATION" is typed as {OP} {ER} {AT} {IO} N, but {NO} is also a common bigram and I find that my right Middle finger lingers over 'O' as I press 'N' so it would be just as true to say that I type it as {OP} {ER} {AT} I {ON}.
I am not too consistent. How I type depends on the word. The keys in the middle of the keyboard (Y, G, B) are typed with different hands depending on the word. I sometimes type bigrams {TY} and {GH} as Index/Middle finger combos, but not always.
Some keys on the far right of the keyboard are typed mostly with the right Ring finger. I press Enter and Backspace with the Ring finger.
I use the right Shift for shifting keys on the far right and for that I use the right Pinky.
Many times I press large keys on the far right with two fingers together. Sometimes the Pinky is there to reinforce the Ring finger when pressing Return and sometimes the Ring finger is there to reinforce the Pinky when pressing Shift. The Ring finger can sometimes be reinforce with the Middle finger when pressing Backspace, but never with the Pinky.
Gah.. All this analysing of my typing style muddles up my typing of this post... Heisenberg's principle definitely applies here..