For the past several months the Jackson Shop, a mom and pop retail store, has suffered costly losses due to the theft of merchandise. Putting in a comprehensive surveillance system that covers all of the entrances and exits at all four of their locations is not feasible at this time. Nevertheless, they have decided to install several surveillance cameras in their flagship store. They notified their employees that the cameras were being installed and placed posters at the store entrances notifying their customers of the new security. Not surprisingly, thefts decreased dramatically within a month and continued to decline over the next six months. Without the cash to install cameras in all the stores, Adams installed fake cameras at the other three stores and let employees and customers at those locations know about the cameras. Thefts dropped at the other stores as well. The concept that most likely explains why the thefts decreased is known as: