I'm reading an extraordinarily important and fascinating book: What's Going on in There: How the Brain and Mind Develop in the First Five Years of Life (Lise Eliot, 1999, Bantam Books). I'll probably end up making several blog posts out of quotations from this book, so here's a start. I always wondered why deliberate smiles, such as those manufactured for photographs or in an attempt to look more cheerful than one actually is, usually look so false:
[S]miling is not voluntary. Although you can willfully concoct your face into a smile, this kind of “polite” smile uses only the muscles of your mouth. Genuine smiles, by contrast, also involve a specific muscle that surrounds the eye, the orbicularis oculi, and movement of this muscle is entirely involuntary.
