Table 1.

Scoring of Different Error Types

	Definition	Scoring	Rationale
Detection errors	First trial on which participants could detect a rule change, i.e., the first negative feedback following a rule change (Figure 1)	Detection errors were excluded from analyses	Detection errors are necessary to find out that the sorting rule has changed
Efficient errors	Incorrect trials that resulted from switching to the wrong rule immediately following the detection of a rule change and led to correct performance for all subsequent trials in the sequence (Figure 1)	Efficient errors were counted as correct	Efficient errors reflect optimal switching behavior
Other errors	All other errors, including repeating the previous rule following the detection of a rule change (i.e., perseverations) and changing rules but making other errors later in the same sequence	Other errors were counted as incorrect	Other errors reflect sub-optimal switching behavior