In a video of the emotional reunion, originally posted on Stevie's mom's Facebook page, the boy breaks down in happy tears at the sight ... hardly watch this without crying," his mom, Diane ...

A little boy's act of sharing his birthday cake with his brother led to an unexpectedly touching moment. The younger brother was overcome with emotion and began to cry ... boy's tears: "In Brazil ...

We usually associate emotional tears with sadness and grief. Why, then do we also cry when we're overcome with positive emotions like joy or relief? Yale psychologist Oriana Aragon co-authored a ...