Your entire life is a LIE! Okay, you’re probably like, “Tell me something I don’t know,” but seriously, your brain makes things up for just about everything. Is the dress blue/black, or is it white/gold... according to the recent poll, it was practically 50/50. Why do we see the same image so differently, you may be wondering? Well I’m glad you asked! In order to understand this, we first need to realise that the concept of colour in itself does not exist in the outside world, that is in the light or the object itself, but rather in our brains, shocking! All light is are tiny little photons bouncing off of objects travelling at different frequencies, and when it hits our retina (eye area filled with photoreceptors), it sends electrical action potentials to the brain which then decodes it causing the perceptual experience of colour. The reason we see the dress so differently has to do with something known as colour constancy and the retinex theory. This states that the cortex (outer potion of the forebrain) compares information from various parts of the retina to determine the brightness and colour for each area. This is actually why you are able to generally determine colour in even low lighting when the object is actually grey, and also responsible for multiple fun optical illusions! Whenever we see anything, we make an inference. For example, when you look at an object, you ask yourself, “On occasions when I have seen something that looked like this, what was it really?” With the dress, if you have had more exposure to dark coloured dresses you probably saw blue/black, whereas if you’ve been around more light coloured dresses you probably saw white/gold. Another factor, combined with the image’s ambiguity, is whether you interpreted the lighting as blue light or yellow light, influencing your inference. Similarly, even your native language and culture can influence your perception of colour! You go through the same process for perceiving shapes, motion, or anything else. That is, visual perception requires reasoning and inference, not just retinal stimulation! So basically, your entire life consists of your brain just making things up to fill in the gaps.