I feel threatened => I immediately (without any analyzis) "threaten back" by showing my teeth (beware, I will bite you!). Then I understand there is no threat,

I feel threatened => I immediately (without any analyzis) "threaten back" by showing my teeth (beware, I will bite you!). Then I understand there is no threat, and I disguise this first (inadequate) instinctive reaction by transmuting it into something which progressively became recognized as a smile/laugh. There is another similar theory about a dog barking and running at his master because he didn't reckon him as such (many dogs are short sighted), then understanding his mistake and also transmuting this aggressive instinctive response into a "dance" (barking at and standing up towards his master).