MCGHEE TYSON AIR NATIONAL GUARD BASE, Tenn. --
Is a smile contagious? Some scientists think so.
Emotion studies at Harvard Medical University
report that our positive relationships and social connections can increase our happiness, and it can even spread and build up, much like a cold.
Of course many of us may already know that. The famous American musician Louis Armstrong did not need an elaborate study to tell us about happiness through a song, years ago:
"When you're smilin' ... the whole world smiles with you ... but when you're cryin' you bring on the rain."
For some of us it's not always easy to smile. So there are these 21 photographs linked here
of our Airman Leadership School students, who were smiling in their classrooms June 21 at the I.G. Brown Training and Education Center in Louisville, Tenn.
If you're feeling down, then look though these captured images at the linked slideshow
, and you may feel it becomes difficult not to smile.