Optical Illusions and How Colour Can Trick Your Eyes

In 2015, social media sites all over the world erupted over the colour of a dress. One group of people thought it was blue and black, and the other thought it was white and gold. No matter how much the other side insisted, everybody was convinced they were correct and the others clearly needed their eyes testing.

Of course this now-famous dress was eventually confirmed to be blue and black, much to the annoyance of millions worldwide. But the actual colour of the dress didn’t really matter — what was interesting was how this simple photo beautifully illustrated how colour and lighting can dramatically impact on what we see, and how our eyes have evolved to see colour in a world filled with sunlight.

The uncomfortable truth is that we can’t always trust what our eyes tell us. Our perception of the world is, whether we like it or not, often different to reality — but why is this the case?

We are visual creatures, in fact, over half of the brain’s cortex is devoted purely to vision. But even with this processing power our brains simply cannot handle all of the information presented by our eyes, forcing it to use cognitive ‘shortcuts’ in order to process and interpret all of the information. Essentially, our brains are constantly making assumptions about the world around us, and often these assumptions turn out to be wrong.

Nothing better demonstrates this than optical illusions, which are specifically designed to illustrate the assumptions and shortcuts made by the brain. The below infographic, courtesy of Cartridge People, looks at this phenomenon, showing you how colour and shape really can trick the eye: