Forget the pills, hypnosis, and meditation. Losing weight or boosting self-confidence can be achieved by adopting an avatar and living in virtual reality, says Jeremy N. Bailenson, an assistant professor of communications at Stanford University. As the director of Stanford's Virtual Human Interaction Lab, Mr. Bailenson has explored ways that online behavior spills over to the real world. People assume that, if anything, online activities emanate from offline lives. Mr. Bailenson and his colleagues have shown the reverse. Their experiments demonstrate, for instance, that people who watch their avatars--cartoon-like versions of themselves--gain weight from overeating are more likely to adopt a weight-loss plan in real life. This research, which Mr. Bailenson described in February at a conference at Stanford, has impressed psychologists and holds promise for improving people's health and well-being. He acknowledges that it can be used in a sinister way, too. Marketers could use virtual reality to try to manipulate what people buy or which political candidates they back.