I don't think we can compare humans to machines... maybe if we somehow understand exactly how reactions work, we could apply that to machines and they can be more similar to us. We could argue that the mechanism of reaction is same - for both machines and human, such that reaction is an outcome of a stimulus, but the choice and decision is different for situation that they are in. anyway, machines can produce same result over and over. Humans cannot, there are many factors such as your arm might get tired, or you lost your interest and attention, etc. my experiment produced random result for my response and stimulus times but mostly stimulus produced faster times.