Why being left out actually hurts
Brain scans show that social rejection lights up some of the same areas as physical pain. Your body treats loneliness as an injury.

"It hurt" is how almost everyone describes being ignored, excluded or rejected. It turns out that isn't just a figure of speech.
In a well-known experiment at UCLA, volunteers lay in a brain scanner and played a simple online game of catch with two other players. After a while, the other two stopped throwing the ball to them. There was no money at stake and the "players" were strangers. Yet as people were left out, a region of the brain called the anterior cingulate cortex became more active, and the more upset people said they felt, the stronger the signal. That same region is closely involved in how we feel the distress of physical pain.
A later study found something even stranger. People who took an ordinary painkiller daily for three weeks reported fewer hurt feelings in daily life than those on a dummy pill, and their brains reacted less to being left out. (That is not a reason to take painkillers for heartache. It is a clue to how closely the two kinds of pain are wired together.)
Scientists think this makes sense. For most of human history, being cut off from the group was as dangerous as a wound. Pain is how the body gets our attention.

