Scientists at the University of British Columbia have found that looking at someone who appears sick boosts your immune system. Subjects had blood taken before and after watching a 10-minute slide show that contained disturbing images including people who appeared sick. Results of the blood tests showed people who had seen the sick people had a stronger immune system. From the article: "In the study, young adults were asked to watch a 10-minute slide show containing a series of unpleasant photographs. Some pictures included people who looked obviously ill in some way. The subjects' blood samples were then tested for levels of interleukin-6 (IL-6), a substance produced by the immune system that indicates your immune system is ramping up to more aggressively fight infection. As a control, pictures of people brandishing guns were also used on some participants—and they barely resulted in a significant increase in IL-6 production, signifying that IL-6 production is not simply a reaction to stress."