In 2007, the Corporation for National and Community Service compiled a series of studies from sources like Duke University and the University of Texas to look at the correlation between volunteering and physical health. Their discovery: Giving back lowers rates of depression and improves long-term health. The social ties it creates can even improve immunity. Recent studies have shown that when people want to contribute to something, the brain lights up the mesolimbic pathway. "That part of the brain is associated with good feelings like joy and feel-good chemicals like dopamine," says Stephen Post, director of the Center for Medical Humanities, Compassionate Care, and Bioethics at Stony Brook University and author of Why Good Things Happen to Good People. "Even just making a charitable donation or thinking about it can have an impact neurologically."