TEST

Choice Reaction Time (CRT)

Perceptual decision-making and response selection

Measures speed in discriminating between stimuli and choosing the correct response. The most direct and basic measure of decision-making speed in the SPAIn battery, essential for driving or work.

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2

STIMULI

~620

REFERENCE MS

9

INDICATORS

WHAT THE TEST IS

Deciding before acting

Inspired by the Choice Reaction Time task by Chiaravalloti et al. (2003) and implements the context control level proposed by Koechlin and Summerfield (2007).

It shares the processes of the SRT but adds uncertainty processing: the user does not know which stimulus will appear next. It measures visual perceptual decision-making time and response selection (Jensen, 2006), incorporating elements of selective attention.

HOW IT IS ADMINISTERED

Square → left · Circle → right

The user must respond with the left hand if a square appears and with the right hand if a circle appears. They must decide before acting: each stimulus requires discriminating, retrieving the associated rule, and executing the correct motor response.

WHAT THE TEST MEASURES

Indicators and their interpretation

Correct responses

Correct identification of the stimulus and keypress with the assigned key. Reflects integration between perception, decision, and action.

High: good discrimination, selective attention, and motor control.
Low: difficulties discriminating, retaining the rule, or planning the response.

Omissions

Stimuli with no response. Attentional lapses or perceptual/motor failures.

High: attentional disconnections, fatigue.
Low: adequate sustained attention and engagement with the task.

Commissions

Keypresses with the incorrect hand. Inhibitory control in multiple-choice selection.

High: impulsivity or over-response.
Low: adequate inhibition.

RT in correct responses

Mean time to identify the stimulus and issue the correct response. The most direct measure of decision-making speed.

Slow: slowing, discrimination difficulties, excessive caution.
Fast: perceptual-decisional agility (if correct responses are present).

RT in commissions

Mean time in incorrect responses. Characterizes whether the error was impulsive or due to confused processing.

Slow: confusion, indecision, difficulty maintaining the rules.
Fast: impulsivity, errors due to rushing.

RT variability

Dispersion of correct RTs. Consistency in decision-making and execution.

High: unstable pattern, attentional fluctuations, or uncertainty.
Low: uniform performance.

RT fatigue

Change in RT between the final 25% and the initial 25%. Detects cognitive or motor fatigue.

Increase: progressive fatigue.
Stable: good attentional endurance.

Post-error slowing

Increase in RT after a commission. Reflects the automatic monitoring and self-correction mechanism.

Mild increase: healthy adaptive adjustment.
Excessive increase: over-monitoring, doubt.
No change: possible absence of the mechanism.

Speed-accuracy tradeoff

Relationship between RT and proportion of correct responses. Strategy adopted.

High: bias toward speed or accuracy.
Low: optimal balance.

REFERENCES

Bibliography

Chiaravalloti, N. D., Christodoulou, C., Demaree, H. A., & DeLuca, J. (2003). Differentiating simple versus complex processing speed: Influence on new learning and memory performance. Journal of Clinical and Experimental Neuropsychology.
Koechlin, E., & Summerfield, C. (2007). An information theoretical approach to prefrontal executive function. Trends in Cognitive Sciences.
Jensen, A. R. (2006). Clocking the mind: Mental chronometry and individual differences. Elsevier.

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