American teens are 40 percent less empathetic than they were three decades ago. Recognizing that students need more than academic rigor to succeed, a growing number of schools are turning their focus to social-emotional qualities like empathy. But which practices enhance empathy and how will principals know if teachers are implementing them effectively? Michele Borba, author of the best-selling book "UnSelfie: Why Empathetic Kids Succeed in Our All-About-Me World," shares nine teachable competencies that can serve as a principal's guide for empathy education.