In the classical Stroop test, subjects are asked to name the color of ink (red, green, blue etc.) in which is written various color words. These either match the ink colour (congruent condition) or contrast with it (incongruent condition). Performance is rated by differences in errors and reaction times across these two conditions. Other versions of the task involve congruent and incongruent non-verbal stimuli (e.g., matching one or two taps, or producing the opposite number of taps. copying a hand action, or producing a different hand action). The test is named after J. Ridley Stroop (1897-1973) who first reported the effect in 1935.
See Executive function (EF), Go/no go test, Embedded Figures Test (EFT), Motor inhibition