When I kept the book, I found this reference invaluable.
https://img.mlbstatic.com/mlb-...yxqioipb87os1puw.pdf
This is a link to the official scoring rules. See page 123. Missed bounced balls (on a throw) are scored as throwing errors. No need to touch the ball for it to be scored as an error. The rules do not provide for mental errors, with an exception as described.
That being said, a ball player’s defense cannot be judged by his stats alone.