Facial Expressions of the Blind
Our general physical behaviour like speech and posture are usually contributed to our environment. It was gernally believed that facial expressions came from those we grew up with. Well, apparently this is not entirely the case according to a recent study:
A blind young man shares his mother's habit of compressing his lips together when puzzled, despite never having seen her face. This is just one of the examples cited as part of a study published online today in Proceedings of the National Academy of Sciences USA showing that relatives who have never seen one another nonetheless share similar facial expressions--proof that even a grimace may be hereditary.
Even relatives separated at birth shared expressions: The blind young man mentioned above was abandoned by his mother two days after birth and not reunited with her until he was 18 years old, yet they shared at least three facial expressions, which reinforces what Darwin suspected more than 100 years ago. As he wrote in The Expression of the Emotions in Man and Animals: "The inheritance of most of our expressive actions explains the fact that those born blind bear them, as I hear from the Rev. R. H. Blair, equally well with those gifted with eyesight."
That Darwin chap was certainly a clever one.