I read "Man Watching " by Desmond Morris when I was young. It was a follow up to his more famous "The Naked Ape". He was a zoologist and presented a TV programme: I think it was called Zootime.    His premise was that, if we observe human behaviour in the same way that we can study animal behaviour, we can find the "body language" that is universal to the human condition. He came up with lots of examples of innate and universal gestures and also explored their origins and significance. (His books are probably an easier read than Darwin's book as well.)