The Stroop Test is a well-known neuropsychological test named for John Ridley Stroop, who published on it in English in 1935. It has found many applications since. It tests how flexible and fast your thinking is, basically, and is used in many different situations. The name of a colour is presented with the typeface in a different colour; your ability to say the colour and not the word, and how long it takes you, reveals your reaction to the interference.

(Dr. John Grohol Pick)