Click on the "Kappa" button to demonstrate the Kappa effect. Click on the speaker button to mute/unmute the sound effects. The effect should work best when sound is off.
The Kappa effect is an illusion that has to do with time perception. It states that if sensory stimuli are applied at different locations consecutively in equal intervals, then if the stimuli are too close to each other, then observers will tend to underestimate the elapsed time between the stimuli. Likewise, when the stimuli are too far away from each other, then observers will tend to overestimate the elapsed time between the stimuli. In think case, when you click on the "Kappa" button, the time between the red and yellow light going off should feel shorter than the time between the yellow and green light going off. If you are a nerd like me and want to learn more, you can visit: https://en.wikipedia.org/wiki/Kappa_effect