According to theAccording to the Pew Research Center, 72% of Americans say tipping is expected in more places today than it was five years ago. It seems everywhere you make a transaction the swiveling iPad is urging you to choose a percentage to tip before you sign.

This cultural shiftThis cultural shift in our consumer activity is not only disconcerting but can leave us feeling guilty or manipulated. In this edition of Two Guys on Your Head, Dr. Art Markman, and Dr. Bob Duke explore the psychology of tipping.