Did you have trouble naming the color of the word when the word didn't match its color? This is one of the strongest effects in experimental psychology, and it was first described by J.R. Stroop in 1935. If you try to name the physical color of a word, the word itself can "interfere" with the process of naming the color of the word. If the word and color don't match (incongruent), it often takes longer to name the color. If the word does match its color (congruent), it usually takes less time to respond. If you are like most people, your incongruent response times will be longer than your congruent response times.