Have you ever spent time looking high and low for something that you just can't find – your keys, your phone, a bag, a book – only to have somebody else point to it straightaway, right there in plain view? It can be so frustrating!
It's well established in biological science that not everything a person 'sees' at any given moment is really there. Where the optic nerve connects to the retina at the back of each eye is a spot with no photoreceptors. Every image that our brain receives from our eyes has a 'blind spot'. Remarkably, our brain fills the hole so what we 'see' is a combination of what our eyes report and what our brain believes to be there.