Splitting Colors

2015 First prize
Mark Vergeer: “Splitting Colors”. KU Leuven (Belgium)

The Splitting Color illusion is all about how we perceive colors. We start off with two identical, flickering colored stripes that remain unchanged throughout the demonstration. However, different surroundings will make these stripes appear completely different. When the stripe is flanked by a yellow/blue pattern, drifting to the left, it changes appearance, and looks red and cyan, drifting to the right, while the same stripe, flanked by a red/cyan pattern drifting to the right, suddenly looks yellow and blue, drifting to the left. This illusion shows that one and the same object can look completely different depending on its surroundings.

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Ambiguous Garage Roof

2015 Second prize
Kokichi Sugihara” “Ambiguous Garage Roof”. Meiji University (Japan)

A round roof of a garage changes its appearance to a corrugated roof when it is reflected in a mirror. The actual shape is neither round nor corrugated. This illusory solid was discovered by combining two observations. One is a mathematical observation that a single image does not covey depth information, and the other is a psychological observation that the human brains like right angles in interpreting an image. Indeed we are apt to interpret the edge curve of the roof as an intersection of a roof with a plane perpendicular to the axis of the roof.

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The Day it Rained on Lowry

2015 Third prize
Michael Pickard: “The Day it Rained on Lowry”. VisuallyDirectedDesign.com (UK)

In Lowry’s Returning from Work, we see the industrial landscape and ‘matchstick’ figures typical of the artist, with bent figures appearing immobilised and struck down in the art of fixation.
However, this illusion changes all that as the figures seemingly start to shuffle along!
In reality, the characters are moving backwards and forwards and only seem to shuffle because a perceptual bias has been created that favours seeing the small forward movement. This appears much larger to the viewer who, in a way similar to how we navigate through crowds using just passing glances, unconsciously extrapolates the movement forward.

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Star Wars Scroll Illusion

– Arthur Shapiro: “The Star Wars Scroll Illusion”. American University (USA)

In the Star Wars movies, the opening sequence shows words scrolling from the bottom of the screen into the distant void of space. Here, we place two copies of a scrolling text side by side. Since the texts are identical, we might imagine that they would appear to run parallel to each other. What we see, however, is one scroll appearing to move toward the upper left of the screen, while the other appears to move toward the upper right. Our brain’s interpretation of the 3D perspective therefore differs from our brain’s interpretation of the parallel lines on the screen.

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The third hand illusion

– Luke Bashford and Carsten Mehring: “The third hand illusion”. Bernstein Center Freiburg, University of Freiburg (Germany)

We present the ‘Third Hand Illusion’, investigating whether it is possible for humans to feel that a virtual reality (VR) hand could be an additional part of their body which they also control. The illusion is created when subjects believe they control movements of the VR hand using a Brain-Computer Interface (BCI), a device that can translate human brain activity into movements of a prosthetic hand. During the illusion participants felt as though they had an independent third hand despite the VR hand movements being artificially generated in time with the user’s intention but not specifically related to brain activity.

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The Honeycomb Illusion

– Marco Bertamini and Nicola Bruno: “The Honeycomb Illusion”. University of Liverpool (UK)

The honeycomb illusion is about how we see a texture that extends in front of us. It is useful therefore to see it on a reasonably large screen. Small segments (barbs) are added to the intersection of a regular grid (honeycomb). They are perfectly visible where you fixate, but everywhere else they disappear. Move your gaze, and now the barbs are visible in a new location, and no longer where you were fixating a moment ago. (Fine details are not well preserved in a compressed video, so please excuse the imperfections. Voice by Giulia Rampone).

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Disambiguating #theDress

– Rosa Lafer-Sousa: ”Disambiguating #theDress”. Massachusetts Institute of Technology (USA)

Typically the visual system does a remarkable job of inferring the spectral-content of ambient light in a scene and discounting its contribution to color perception. But what if the relevant cues are ambiguous? Perhaps people perceive #TheDress differently because the lighting in the image is ambiguous (is it warm or cool?) and people’s brains make different guesses about it’s chromatic-bias. Here, I disambiguate the lighting conditions by embedding #TheDress in scenes containing clear cues to the illuminating conditions: the scene and model’s skin cue either a warm or cool light (the dress was not modified). Most viewers (~80%) conform to the cued percept.

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The Wandering Circles

– Christopher Blair, Lars Strother, and Gideon Caplovitz: “The Wandering Circles”. University of Nevada, Reno (USA)

Flickering circles with a light and dark side at their edge (also known as Craik-O’Brien-Cornsweet circles) appear to wander. Even though these circles are not moving (only flickering), the shapes seem to drift whenever you do not look directly at the circles. Even if you put a line right next to a circle, the shape will still seem to move, but never across the line. The more circles you add, the more motion you see!

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Snow Blind illusion

– Masashi Atarashi: “Snow Blind Illusion”. Physics teacher at Aichi Prefectural Gojo Senior High School (Japan)

The “Snow Blind illusion” is very simple, but once you know this phenomenon, you can not wait for winter. The speed of falling snowflakes appears to be accelerated by blinds.

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Mind-controlled motion

– Nicolas Davidenko, Yeram Cheong, and Jacob Smith, University of California, Santa Cruz (USA)

Which way does the motion go? Is it up and down, or right and left? The truth is, the motion is entirely in your mind! In this demonstration, you first see a random texture moving up and down for 5 frames. After those priming frames, the remaining frames are completely random, but you will continue seeing up and down motion for several more frames. To convince yourself that this is all in your mind, try thinking to yourself “right left right left”. The same sequence of random textures will appear to move whichever way your mind decides.

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