When my wife and I tale the morning walk, we are invariably accompanied by Georgie, our little pavement-special of a dog. Her reaction to passing dogs is interesting: - Sometimes a mutually respectful sniff - Sometimes happy to ignore the dog blissfully - And sometimes she gets ropable and wants to attack There is no pattern – presumably they smell something, but whatever the reason, the reaction is varied and instantaneous. Made me thing of BLINK (Malcolm Gladwell’s book) and wonder if people are like that too? Maybe we just disguise it a bit better?