In the study of bystanders and thieves presented in the text, participants are invited to a store where they see someone steal the purse of another customer. The accosted shopper and the thief are really acting their parts to set the stage for the experiment. Participants view the robbery alone or with another participant. The study sought to determine whether participants were more likely to report a robbery when they observe it alone or in the company of another person. The actors playing the role of the accosted shopper and thief in the bystanders and thieves study are known as .