A modern version of Donders’ (1868) reaction time experiment: (a) the
simple reaction time task; and (b) the choice reaction time task. In the simple reaction time
task, the participant pushes the J key when the light goes on. In the choice reaction time
task, the participant pushes the J key if the left light goes on and the K key if the right light
goes on. The purpose of Donders’ experiment was to determine the time it took to decide
which key to press for the choice reaction time task.