The lilac chaser is a visual illusion, also known as the Pac-Man illusion.[1] It consists of 12 lilac (or pink, rose, or magenta), blurred discs arranged in a circle (like the numbers on a clock), around a small black, central cross on a grey background. One of the discs disappears briefly (for about 0.1 seconds), then the next (about 0.125 seconds later), and the next, and so on, in a clockwise direction. When one stares at the cross for at least 30 seconds, one sees three illusions
- A gap running around the circle of lilac discs;
- A green disc running around the circle of lilac discs in place of the gap; and
- The green disc running around on the grey background, with the lilac discs having disappeared in sequence.
The illusion was created by Jeremy Hinton some time before 2005. It then spread widely over the internet.[2] It is a visual illusion that demonstrates color adaptation or human visual perception.[3]
The chaser effect results from the phi phenomenon illusion, combined with an afterimage effect in which an opposite color, or complementary color – green – appears when each lilac spot disappears (if the discs were blue, one would see yellow), and Troxler's fading of the lilac discs.
- ^ "The Lilac Chaser aka Pac-Man Illusion". Archived from the original on April 16, 2008.
- ^ Bach, Michael (2014). "Visual illusions on the internet: 15 years of change in technology and user behaviour". Perception. 43 (9): 873–880. doi:10.1068/p7708. PMID 25420328.
- ^ DeValois, K. K.; Webster, M. A. (2011). "Color vision". Scholarpedia. 6 (4): 3073. Bibcode:2011SchpJ...6.3073D. doi:10.4249/scholarpedia.3073.