What size of your SMILE say’s about you?

 A pair upturned lips, the smile is the most scientifically studied human facial expression. The latest reaserch  of professor Marianne Lafrance, PhD, in fields from biology to anthropology to computer science in an effort to shed some light on the happy face.

People with big grins live longer.

 In a study They found that on average, the guys with bright, bigmouthed beams lived 4.9 years longer than the players with partial smiles, and 7 years longer than the players who showed no grin at all. We can't credit wide smiles for long life spans, of course, but smiles reveal positive feelings, and positive feelings are linked to well-being.

There are three degrees of happiness...   it is indeed possible to spread the love: Within social networks, when one person is happy, the feeling migrates to two people beyond her. So if you smile, a friend of a friend is more likely to smile, too.

and two types of smiles. Genuine smiles and fake smiles are governed by two separate neural pathways. 

We know this is true because people with damage to a certain part of the brain can still break into a spontaneous grin even though they're unable to smile at will. Scientists speculate that our ancestors evolved the neural circuitry to force smiles because it was evolutionarily advantageous to mask their fear and fury.