According to researchers, the human brain puts strangers in one bin and the people we know in another compartment. People in your social network literally become entwined with your sense of self at a neural level. "With familiarity, other people become part of ourselves," said James Coan, a psychology professor in University of Virginia's College of Arts & Sciences who used functional magnetic resonance imaging brain (fMRI) scans to find that people closely correlate people to whom they are attached to themselves.