Laughing Eyes

In his song Snowin’ on Raton, Townes Van Zandt sings  ”shall I cast my dreams upon your love babe / and lie beneath the laughter of your eyes.”  Part of what makes Townes an amazing musician is that his lyrics are surprising – the words aren’t what you’re expecting.  ”The laughter of your eyes” is a good example of this: we associate laughter with the mouth, or the voice, or even the diaphragm, rather than the eyes.  However, Townes is right on here.  I doubt that he read Paul Ekman’s 1978 manual on the Facial Action Coding System, but these lyrics highlight an interesting human behavior: we have 2 distinct types of smiles that we use in different circumstances.  First is the generic smile that we use to be polite when acknowledging others in social contexts.  This generic smile is produced by the contraction of the zygomatic major muscle which raises the corners of the mouth.  The second smile is a genuine smile associated with uniquely positive emotions. A genuine smile is also called a Duchenne smile, after it’s discoverer,  Guillaume Duchenne, who was a mid-19th century physiologist.  A Duchenne smile is formed by adding the contraction of the theorbicularis oculi muscle, which raises the cheeks and forms crow’s feet around the eyes.  Most people have conscious control over their generic smile, but interestingly, around 80% of people cannot voluntarily contract their theorbicularis oculi muscle.  So, true laughter and happiness are reflected by the eyes, as Townes wisely points out.