errors of omission have been shown to result from cognitive vigilance decrements, while errors of commission result from a combination of a failure to take information into account and an excessive trust in the reliability of automated aids. errors of commission occur for three reasons: (1) overt redirection of attention away from the automated aid; (2) diminished attention to the aid; (3) active discounting of information that counters the aid's recommendations. omission errors occur when the human decision-maker fails to notice an automation failure, either due to low vigilance or overtrust in the system. for example, a spell-checking program incorrectly marking a word as misspelled and suggesting an alternative would be an error of commission, and a spell-checking program failing to notice a misspelled word would be an error of omission. in these cases, automation bias could be observed by a user accepting the alternative word without consulting a dictionary, or a user not noticing the incorrectly misspelled word and assuming all the words are correct without reviewing the words.