I was recently advised to read "The Vision Revolution" by Mark Changizi as its pertinent to a field I'm doing some work on. It's about how our sight works. (It's 'popular science' - but will probably require a couple of reads to get full sense out of it). Changizi is full of insight as to how our vision works and this one in particular interested me. Because it takes about 1/10 of a second between light hitting our eyes and our reflexes kicking in, our brain pre-processes the information and what we actually see is the brain's interpretation of where an object will be allowing for our reflexes. The result can be seen in the diagram below. In the diagram on the left, if we saw the balls' actual position, our reflexes would mean that we'd always be grabbing at the ball a tenth of a second after where it actually was - and get it in the face. What actually happens is on the right. We 'see' the ball a tenth of a second on from its actual position - so allowing for the time lag in our reflexes. So the errors cancel out and we can catch the ball. So we don't see the real world - we see our brains' projection of how it thinks things will be 1/10th of a second into the future - and we never realise it. This has been proven using simple experiments. In the diagram on the left a light bulb has been set to flash the precise second that a ball passes it. However, when people are asked to estimate the relative positions of the ball and light, they always 'see' the ball a fraction in front of the light as that's the mental image we are presented with. The truth is stranger than fiction. Wordsmith (Cue lots of jokes about people who live 1/10 second behind the real world).