We’ve all known—or at least heard about—people who are simply more selfless than the rest of us. While on the surface, this may seem like something we can write off as a trait they were born with, psychologist Abigail Marsh suggests that we all have the ability to act with altruism. In this insightful TED Talk, she explores the science behind altruism and the atmospheres that foster it, and provides some practical advice on how we can activate it in our own lives.