The five major human senses are sight, hearing, touch, taste, and smell. Our brains integrate stimuli coming from each, and combine that data to make sense out of our environment. Input from one sense can alter our perception of input from another sense, as the Rabbit Illusions from CalTech shows. The first illusion is called the Illusory Rabbit, shown in this video, and the second is the Invisible Rabbit, which you can see attached to the research paper abstract. CalTech also gives us a simple explanation of each illusion. Honestly, I only saw two flashes, but since both my eyesight and my hearing are not what they used to be, I second guessed myself and assumed I must have missed a flash. However, the research addresses the idea that our perception can change due to information added later. I haven't yet seen an explanation of why they called it the Rabbit Illusion. -via Boing Boing
From an article in Popular Mechanics.