Table 1.

Processing Speed Measures Ranked from Low to High in Estimated Executive Control Contributions

	Working Memory	Decision-Making	Response Selection	Interference Control	Motor Control	Pre-existing Knowledge
Prosaccade LatencyE1	minimal	minimal	minimal	minimal	minimal	minimal
Offset RTB,E1	low	minimal	minimal	minimal	low	minimal
Simple RTE1	low	minimal	minimal	minimal	moderate	minimal
Box CompletionB,E1,E2	low	minimal	low	low	high	minimal
Horizontal MarksE1	low	minimal	low	low	high	minimal
Digit CopyingE1,E2	low	minimal	high	low	high	low
Color NamingE1	low	moderate	high	moderate	low	low
Choice RTB,E1,†	moderate	low	moderate	high	moderate	low
Digit-Symbol	moderate	low	high	moderate	high	low
SubstitutionE2
Addition and	moderate	minimal	high	moderate	high	high
SubtractionE1
Letter ComparisonE2	high	high	moderate	moderate	high	moderate

Note—Processing speed measures vary in their demands. These variations across tasks also vary by age, with simpler tasks requiring greater executive control in children and older adults than in young adults (variations by age not shown in table). These estimates are rough, some of these factors may overlap, and we have not covered every possible factor on which tasks differ; however, the overall pattern demonstrates important variation across processing speed measures. Criteria for the four levels (specified from minimal to high) for each factor are as follows: Working memory: none required; single goal can be held in working memory throughout entire task; single goal or stimulus held in working memory must be updated during task; additional complex operations on contents of working memory required. Decision-making: no judgment about stimuli required; simple forced-choice judgment; simple open-ended judgment; difficult judgment based on multiple aspects of stimuli. Response selection: no selection involved; one response location must be selected from several; two possible responses exist; more than two possible responses exist. Interference control: no interfering stimuli; surrounding stimuli are present; surrounding stimuli might induce errors; interference within target stimulus. Motor control: saccade required; hand lift or verbal response required; hand must press specific target among multiple potential targets; fine motor control required. Pre-existing knowledge: none required; knowledge about colors, shapes, or numbers required or beneficial; knowledge about letters and letter strings beneficial; knowledge of mathematics required. While motor control and pre-existing knowledge are not necessarily aspects of executive control, they are included because they may place varying demands on executive control. Dashed line separates psychomotor and perceptual speed tasks. Task was used in study:

^BBlackwell et al. (2009);

^E1Exp. 1;

^E2Exp. 2.

^†see also Footnote 6.