An inner voice can be a healthy thing. It can make us more introspective and enable us to talk through tough feelings in our heads. But sometimes our inner dialogue can be too critical, inducing anxiety and other negative emotions. In his new book Chatter: The Voice in Our Head, Why It Matters, and How to Harness It, University of Michigan psychologist ETHAN KROSS discusses how to calm and control our self-talk and put it to good use.