Blurriness

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 blurriness 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. 
  • Note, depending on your screen size and your distance to your screen, this illusion may even work without making the example full screen.
For more information, see the text below the examples.

 

The peripheral stimuli in all examples are identical. However, when the central stimuli are less blurry (Ex. 1), the peripheral stimuli wane in and out of sharpness, and at moments seem to be entirely sharp. When the central stimuli are more blurry than the peripheral stimuli (Ex. 2), the peripheral stimuli in turn seem to become more blurry, and now never become sharp. Note that this is also an example of the PO illusion occurring easier when the difference between centre and periphery is smaller. In this case the difference in sharpness is larger in the first than in the second example, leading to a slower PO illusion in the first case.