Table 2.

NAT Error Categories

Error Category			Definition	Examples From Toast and Coffee and Present-Wrapping Tasks
Omission			a step or subtask is not performed	does not add sugar to coffee
On-task Commission		Substitution	semantically related or perceptually similar alternate object used in place of target object	spreads butter on toast with spoon instead of knife
		Sequence	a task step is performed out of order, such that the performance of an earlier task step is omitted (anticipation-omission); two steps are performed in reverse order (reversal)	applies butter on bread, without first toasting bread; applies jelly on bread, then applies butter
		Perseveration	a step or subtask is performed more than once, performed repetitively, or for an excessive amount of time	spreads butter on bread repeatedly or for an extended period of time (>19 seconds)
		Other	gesture substitution, tool omission, spatial misestimation, and quality errors	misorients wrapping paper with respect to the gift
Off-task Commission (Additions)			behavior outside of task parameters	eats toast; uses school supplies