© Jonathon Rosen
They're considered a release, a psychological tonic, and to many a glimpse of something deeper: the heart's own sign language, emotional perspiration from the well of common humanity.
Tears lubricate love songs and love, weddings and funerals, public rituals and private pain, and perhaps no scientific study can capture their many meanings.
"I cry when I'm happy, I cry when I'm sad, I may cry when I'm sharing something that's of great significance to me," said Nancy Reiley, 62, who works at a women's shelter in Tampa, Fla., "and for some reason I sometimes will cry when I'm in a public speaking situation.
"It has nothing to do with feeling sad or vulnerable. There's no reason I can think of why it happens, but it does."