To achieve what color vision scientists call 'color constancy,' the brain calculates color-corrections for an image on the fly. Basically, light bounces off objects in the world and reaches your eyes in "a mix of wavelengths," which your brain then interprets as color.Īs Slate's Pascal Wallisch explained, "this mix depends on two things: the color of the object and the color of the light source. In simplest terms, it all has to do with how your brain processes color. There are countless explanations you can read online about why people see the dress as two completely different colors. Roman Originals' Lace Detail Bodycon Dress in Royal Blue ($58). At this point, stimuli in your peripheral vision take on the nature of their surrounding environment - in this case, a white background - as your brain "fills in" information it has deemed unimportant to process. When you force your eyes to focus on one point, the way you do with Troxler-style illusions, your brain receives no new information to process. As Live Science's Brandon Specktor explained, this ability to adapt quickly to stimuli allows your brain to focus on things that are actually important. In simplest terms, your sensory neurons tend to filter out information that is constant - stimuli that your brain has deemed non-essential and non-threatening. So how does it work? Well, this mind-boggling effect is actually a variation of a famous optical illusion called Troxler's fading circle. Discovered in 1804 by Ignaz Troxler, a Swiss physician and philosopher, the Troxler effect illustrates the human brain's efficiency. The image, posted by Dr. David McPhillips of Primary Eye Care Associates, disappears after approximately 30 seconds, when you focus on just one fixed point in the graphic.
In April 2018, an eye-care practice in Horsham, Pennsylvania, tweeted an optical illusion that left some people in disbelief. The result is a picture that can be perceived in two different ways, depending on the distance from which you look at it. Hybrid images work by combining the high frequencies from one photo with the low frequencies from another. But from a distance, sharp details become less visible and we instead register features with low frequencies, such as the shape of one's mouth or nose.
One famous example of a hybrid image overlays the faces of Albert Einstein and Marilyn Monroe, as seen above. As Aude Olivia, the principal research scientist at MIT's Computer Science & Artificial Intelligence Lab, previously explained to Wired, this illusion is often used to study how our brains process visual stimuli and sight.Īccording to Olivia, who has created and used hybrid images in her research for decades, our eyes see "resolutions with both high spatial frequencies (sharp lines) and low ones (blurred shapes)." Up close, we focus on features with high frequencies, such as wrinkles or blemishes.