What time is a good time to expose your children to ugly realities?

Takeaway contributor and “Freakonomics” author Stephen Dubner grapples with the balancing act of being a responsible parent and telling his children some cold, hard truths. Dubner wonders when is the right age ? and what might be the wrong moment ? for a dose of adult-strength reality. Guest: Stephen Dubner, Takeaway contributor and author of the “Freakonomics” book and blog