What is the evolutionary origin of the human smile?

Question

What is the evolutionary origin of the human smile?

Answer 1

I heard that some monkeys made facial expressions, so humans probably got that from them.

Answer 2

It probaly started with the apes showing each other they had no fangs and weren't predators.

Answer 3

happiness and pleasure

Answer 4

Most likely an affiliative gesture. Such smiling can be seen in other social primates.

Answer 5

When ancient people saw the big Clams opening, they're trying to mimic it. And as they mimic the clam their jaw got tired and laugh at each other.

Answer 6

Wind?

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Answer 7

As with all positive mutations, they either increase survivability or increase the chance of reproduction. Smiles do both. Humans that smile are more liked and so less likely to be club to death. Also smiles attract members of the opposite s*x thus increasing the chance for procreation.