Kappa Effect

The Kappa Effect is a psychological phenomenon related to the perception of distance, time and speed. It is a temporal illusion that, in some cases, can alter one’s judgement of time. The Kappa effect arises when observers judge the amount of elapsed time between two stimuli in a sequence of consecutive stimuli. Stimuli can be visual, like flashes of light; auditory, like auditory tones; or tactile, like stimulation of the skin. When a subject is required to make judgments about ambiguous temporal intervals (the length of elapsed time) between each of these stimuli, they often base their decision on the familiar functional relations between spatial separation, time, and average velocity. These estimations of the length of time between stimuli can be influenced by the spatial separation, or the distance, between each of the stimuli. The elapsed time between two stimuli can be made to appear shorter (or longer) by decreasing (or increasing) the distance between the two stimuli Therefore, even when the length of elapsed time between stimuli in a sequence is kept the same throughout the sequence, we tend to overestimate the amount of time between each stimuli when the distance between them is longer. Equally, we tend to underestimate the amount of elapsed time between each stimuli in a sequence when the distance between them is shorter.