Why It Hurts 1 Why It Hurts to Be Left Out: The Neurocognitive Overlap Between Physical and Social Pain Naomi I. Eisenberger & Matthew D. Lieberman Department of Psychology, University of California, Los Angeles Correspondence should be addressed to N.E. (neisenbe@ucla.edu) Department of Psychology, Franz Hall, University of California, Los Angeles, Los Angeles, California 90025 USA