Why Do We Feel The Need To Belong?

The only thoughts I’ll ever truly know are my own. And yet, that doesn’t stop me from wanting to not be alone.

People spend their lives trying to belong: to a spouse, to a family, to a tribe, to a cause, to a country. Where does this need to be more than an individual come from?

Why do we feel the need to belong?

Related questions: Why do we care what strangers think of us? What does it mean to belong to a country? What are our responsibilities to others?