914 / Mona Lisa: Not a Duchenne smile!
One bizarre remark on Mona Lisa's smile is that she doesn't smile at all; it's a visual illusion. And wasn't Leonardo da Vinci a master in optics? Turns out, half of the claim is true -- literally! Neurologists Lucia Ricciardi and Matteo Bolognay have interpreted Mona Lisa's smile as asymmetric and so non-genuine. Happiness is expressed only on the left side. A genuine smile not only utilises the muscles of the mouth but also those of the eyes. It is a Duchenne smile (named after Guillaume Duchenne, a 19th century neurologist who studied the signs). An asymmetric smile is a non-Duchenne smile. It "reflects a non-genuine emotion and is thought to occur when the subject lies." Ricciardi and Bolognay came up with an intriguing possibility -- that Leonardo knew the true meaning of asymmetric smile more than three centuries before Duchenne's finding and that he intentionally painted a smile expressing a 'non-felt' emotion! If the theory holds, then Mona Lisa's...