Ran across this link earlier today and it’s a pretty interesting read about facial expressions. It goes on to say that emotional facial expressions are innate and not learned visually. It goes over a study where it compares sighted athletes to blind ones and how they produce similar expressions.
There’s also a useful bit in there about the difference between social smiles and true smiles. Social smiles use just the mouth area, whereas true ones cause the cheeks to rise and eyes to narrow.
Link: Facial expressions of emotion are innate, not learned, says new study



