It's hard to resist a good illusion, but they're not simply fun because of the mind-blown factor -- they also teach us important things about how we perceive the world around us. Take the debacle around The Dress -- the difference in perception around the garment's colour was actually an illusion as people's brains subconsciously tried to correct for the light source behind it.
The Neural Correlate Society, a non-profit that promotes scientific research into perception and cognition -- neural correlates, or neural processes that correlate -- also promotes new discoveries to the public. As part of this work, it hosts an annual contest, beginning in 200,5 to highlight the best new illusions, either unpublished or published no earlier than 2014.
The winners of the Best Illusion of the Year Contest 2015 are now in.
First prize: Splitting Colours
Mark Vergeer of Katholieke Universiteit Leuven, Belgium conceived the Splitting Colours illusion, playing with how we perceive colour. Two identical flickering stripes of colour are shown; yet, when they are surrounded by moving larger stripes in blue and yellow, then red and cyan, the thinner stripes appear completely different -- showing how colour can appear to change depending on the colours around it.
Second prize: Ambiguous Garage Roof
Ambiguous Garage Roof by Kokichi Sugihara of Meiji University, Japan, is a matter of perspective. A roof that looks curved over a car appears to concertina when reflected in a mirror -- yet the roof itself is flat. This demonstrates that depth information cannot be gleaned from a single, two-dimensional image -- and that human brains gravitate towards right angles when interpreting an image.
Third Prize: The Day it Rained on Lowry
Michael Pickard of Virtually Directed Design designed The Day it Rained on Lowry, an illusion that demonstrates our bias towards forward movement. Pickard's image of figures in the rain flickers between two screens -- one of which shifts the position of the figures a few pixels -- in a loop, the figures moving backward and forward. However, because moving forward is more natural than moving backward, we interpret it as a forward-shuffling movement and "edit" out the backward part.