Popular neuropsychological test.[ The words themselves have a strong influence over your ability to say the color. The interference between the different information (what the words say and the color of the words) your brain receives causes a problem. There are two theories that may explain the Stroop effect: 1. Speed of Processing Theory: the interference occurs because words are read faster than colors are named. 2. Selective Attention Theory: the interference occurs because naming colors requires more attention than reading words.