Density

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 density 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).
  • The first two examples contain no fixation spot, the latter two are identical to the first two, but they do contain a fixation spot. Some people find that the illusion works better without a fixation spot, but you can try out which works best for yourself. 
For more information, see the text below the examples.




More info: In the first example the center has a higher density than the periphery, i.e. there are more dots per area at the centre than at the periphery. If you keep your eyes fixated at the centre of the screen for a prolonged period, the entire screen, at moments, seems to have a higher density, and be filled with more dots than there actually are. In the second example the density of the dots in the periphery is identical to the density in the first example. However, the central density is now lower than the peripheral density. Now, at moments, the overall density seems to drop, and the periphery seems to contain less dots than there actually are. In the first example, the central patch is 50% more dense than the central patch. In the second example, the central patch is 30% less dense than the central patch.