 In order to put this claim to empirical test, it is important to have ways of inducing empathy in the laboratory, and there is a substantial body of literature suggesting how this can be done. For example, Stotland (1969) showed that subjects who were instructed to imagine how a specified person (often called “the target”) felt when undergoing what subjects believed to be a painful medical procedure reported stronger feelings of empathy and showed greater physiological arousal than subjects who were instructed to watch the target person’s  movements.[15]  Relatedly, Krebs (1975) demonstrated that subjects  who observe someone similar to themselves  undergo painful experiences show more physiological arousal, report identifying with the target more strongly, and report feeling worse while waiting for the painful stimulus to begin than do subjects who observe the same painful experiences administered to someone who is not similar to themselves. Krebs also showed that subjects are more willing to help at some personal cost when the sufferer is similar to themselves. Batson (1991: 82–87) interprets these findings as indicating that people are more inclined to feel empathy for those they believe to be similar to themselves, and thus that empathy can often be induced by providing a person with evidence that she and a target person are similar.