A recent study, for example, looked at the persistence of visual images in the brain given dynamic stimuli. Their brain cannot keep up with the rapidly changing visual input. This was the point of the current study – they looked at the different level of visual process while subjects viewed a changing image. Optical illusions reveal the processing, which is why neuroscientists use them as a method of exploring visual processing. Our brain’s visual processing is similar, but has had a few hundred million years of evolutionary tweaking.