The Stroop effect is a classic psychological experiment that studies the limits of our cognitive abilities. The task is simple: you have to name the color of a set of dots, and it takes longer to name the color that is printed on the right. When you do, the color will be clearer to you. The test is named after the psychologist who created it, Dr. John Stroop.

This test is not only a challenge for the brain, but also for the eyes and the hands. If you are tired or feeling lazy, you may find it hard to complete the test.