Elizabeth Dunn: Helping others makes us happier -- but it matters how we do it

Research shows that helping others makes us happier. But in her groundbreaking work on generosity and joy, social psychologist Elizabeth Dunn found that there's a catch: it matters how we help. Learn how we can make a greater impact -- and boost our own happiness along the way -- if we make one key shift in how we help others. "Let's stop thinking about giving as just this moral obligation and start thinking of it as a source of pleasure," Dunn says.