> Wouldn't one notice if they're almost halfway through a word and nothing has shown up on the screen? There is quite a delay between the eye detecting somethi

> Wouldn't one notice if they're almost halfway through a word and nothing has shown up on the screen? There is quite a delay between the eye detecting something and it being consciously processed to the point of being used in decision making. Away from built-in reactions (move hand away from burning sensation and so forth) that are not consciously controlled there is a sometimes surprising amount of latency in our view of the world. It is surprising because the brain does a rather good job of smoothing it out with guesses/predictions such that you generally don't notice. Only when things fall outside the range of patterns you naturally cope with or expect because they are consequences of your own actions, do you really become aware of them. So he might not notice usually, but would if an error or something else unexpected occurred. This is why 100ms, or even sometimes 200ms, is fine for many things, but others cause irritation despite delays of 40ms or sometimes significantly lower. The brain smooths out what it can, the rest sets of warnings of potential trouble.