When nudges go wrong. In an attempt to reduce the theft of wood from Arizona’s Petrified Forest National Park the authors put up a sign with the descriptive social normative message “Many past visitors have removed petrified wood from the Park, changing the natural state of the Petrified Forest”. This led to a near 8% increase in wood theft, as people interpreted the salient message to be “theft is common” rather than “theft is bad”.