Congratulations to the winners of the 15th annual Best Illusion of the Year Contest! Worldwide voters chose the best illusions of the year from 9am EST on December 9th to 7pm EST on December 12th.

These are the mind-blowing illusions that took the top prizes, together with their creators’ thoughts on how their trickery challenges reality:

First Prize: “Dual Axis Illusion,” by Frank Force, USA

This spinning shape appears to defy logic by rotating around both the horizontal and vertical axis at the same time! To make things even more confusing, the direction of rotation is also ambiguous. Some visual cues in the video will help viewers change their perception.

Illusion Chasers: How does your illusion work and what does it tell us about the human brain/mind?
Force: The underlying math equations to form this [illusion] are themselves ambiguous in terms of rotation, so it is interesting how our mind is unable to deal with this and settles into a picture about what direction and axis it is rotating. Also, our mind pictures it as a 3D object while there is nothing actually happening that is 3D.

Illusion Chasers: Does the illusion relate to any experiences we might have in our daily lives?
Force: It shows that things can be perceived in different ways and to truly understand we must look deeper.

Illusion Chasers: How did you discover your illusion?
Force: While making generative art I came across Lissajous/Bowditch curves. I noticed by accident that they seem to rotate around both axes, and looking at the math that is exactly how they are defined. I was aware of the silhouette illusion, which it shares some similarities with, but couldn't find anything about this new variation. This effect applies to other Lissajous curves, but being the simplest non-trivial one, I think this one looks the best.

Second Prize:"Change the Color," by Haruaki Fukuda, University of Tokyo, Japan

In this illusion, either downward or rightward motion perception for the dots is possible. Depending on the perceived motion direction, color changes: red and green dots with downward motion, and yellow dots with rightward motion. This suggests that our perception of color is not simply the result of limitations in temporal resolution of the visual system.

Illusion Chasers: How does your illusion work and what does it tell us about the human brain/mind?
Fukuda: In the video, the viewer can perceive the lines of dots as moving either downward or rightward. Depending on the perceived motion direction, the color of the dots seems to change: red and green dots with downward motion, and yellow dots with rightward motion. Moreover, the viewers’ assumptions can determine in what direction the dots move. This illusion shows that we can change how we see color by intentionally changing our assumptions about motion. In other words, our intentional assumptions can change our perception.

Illusion Chasers: Does the illusion relate to any experiences we might have in our daily lives?
Fukuda: In our daily lives, we sometimes fail to see what really is there, by our own misassumptions. This type of everyday misperception could be based on the same mechanisms as my illusion.

Illusion Chasers: How did you discover your illusion?
Fukuda: I found this illusion by accident when I created a demo showing apparent motion (phi motion) for my cognitive psychology students. I noticed that perceived motion could affect one’s color perception, and I tried different colors to make the illusion as strong and beautiful as possible.

Third Prize: “The Rotating Circles Illusion,” by Ryan E.B. Mruczek and Gideon Paul Caplovitz, College of the Holy Cross and University of Nevada Reno, USA

In the Rotating Circles illusion, the true motion of the central circle is unchanging - it simply rotates around a central point. However, the added motion of surrounding circles leads the perceived motion of the central circle to appear “pulled” and distorted. Even though it is continuously rotating, by fixating the white dot the central circle can appear to move up and down, left and right, even in a triangle. As with other dynamic illusions, the effect is strongest when viewed in the periphery. Viewers can confirm that the central circle is always rotating simply by looking right at it.

Illusion Chasers: How does your illusion work and what does it tell us about the human brain/mind?
Mruczek and Caplovitz: The Rotating Circles illusion demonstrates the relative nature of perception.  An object’s attributes – here, its motion – are often perceived relative to the attributes of nearby objects.  Thus, to understand how our brain construct our experience of a moving object, we must also understand the context in which the object is moving.

Illusion Chasers: Does the illusion relate to any experiences we might have in our daily lives?
Mruczek and Caplovitz:  Importantly, objects in the real world are rarely stationary – motion abounds.  The strong influence of motion in generating interactions between different objects, as demonstrated in the Rotating Circle illusion, is likely to come into play in many everyday situations, such as judging the speed and trajectory of a person or vehicle.

Illusion Chasers: How did you discover your illusion?
Mruczek and Caplovitz:  Our recent work has shown that dynamic motion can greatly enhance the effectiveness of classic size illusions, such as the Ebbinghaus illusion.  In other words, adding dynamic motion to traditionally static displays led to much larger illusory effects.  We stumbled on the Rotating Circles illusion while exploring different combinations and types of motion for the central and surrounding circles of classic Ebbinghaus stimuli.  We were immediately struck by the compelling effects on motion perception when the movement of the central and surrounding circles were not matched.