Motion

More information: Otten, Pinto, Paffen, Seth & Kanai (in press). The Uniformity Illusion: Central stimuli can determine peripheral perception. Psychological Science

Four examples of the uniformity illusion with motion as an example. 
  • Open the video fullscreen.
  • Keep your eyes fixated on the centre of the screen for a good amount of time (tens of seconds to minutes).
  • In the first two examples the central stimuli are present from the start, in the latter two the central stimuli appear after a while. The first and the third example contain no fixation spot, the second and the fourth do. Some people find that the illusion works better without a fixation spot, but you can try out which works best for yourself. 
  • The fifth example is similar to the third, but now all the motion is much slower. 
For more information, see the text below the examples.



In all examples the dots in the periphery rotate four times as fast as the central dots, but all dots seem to be going at the same speed after a while. When the central stimuli appear later (in the latter two examples), it leads, for some people, to a more dramatic effect. Now the peripheral stimuli abruptly appear to slow down. In the last example there can be some strange effects, because now the central motion is very slow. Again the peripheral motion is four times faster than the central motion. When the centre is empty, the periphery can be seen to move slowly and smoothly. However, when the central moving dots appear, the whole screen sometimes seems to become static. The peripheral motion can seem jerky at moments, as if it stops and goes.