valintareaktioaika

Valintareaktioaika, literally meaning "choice reaction time" in Finnish, is a measure of the time required to select and execute a response when a stimulus signals multiple possible actions. It contrasts with simple reaction time, where the same response is given to all stimuli. In experimental psychology the term describes the duration from stimulus onset to initiation of the motor response in tasks that require choosing among alternative responses.

It is typically measured in milliseconds across trials and analyzed as mean or median RT, with attention to accuracy and the shape of RT distributions. Common paradigms include two-choice or multi-choice reaction time tasks. The observed RT reflects multiple processing stages: perceptual encoding, decision-making to select the appropriate response, and motor preparation and execution. The speed-accuracy trade-off means faster responses may reduce accuracy, and researchers often assess both speed and correctness.

Factors influencing valintareaktioaika include stimulus complexity, number of alternatives, stimulus discriminability, participant age, cognitive load, fatigue, motivation, and neurological or psychiatric conditions. In clinical and research settings, CRT is used to assess processing speed and executive function, and is informative in developmental studies as well as in disorders such as ADHD or dementia.

Historically, choice reaction time tasks build on early work by Donders, who compared simple and choice RT to estimate the duration of the decision stage via subtraction methods. Related concepts include decision time and perceptual decision making.

See also: reaction time, choice reaction time, cognitive psychology, neuropsychological assessment.