Happiness is  _ , researchers reported on Thursday. The more happy people you know, the more likely you are yourself to be happy. And getting connected to happy people improves a person's own happiness. Researchers have been analyzing a collection of facts from tracking sheets dating back to 1971, following births, marriages, deaths, and divorces. Volunteers also listed the information of their closest friends, co-workers, and neighbors. They assessed   happiness with a simple, four-question test. "People are asked how often during the past week, one, I enjoyed life, two, I was happy, three, I felt hopeful about the future, and four, I felt that I was just as good as other people," Fowler said. The 60 percent of people who scored highly on all four questions were regarded as happy, while the rest were considered unhappy. People with the most social connections -- friends, spouses  , neighbors,  s -- were also the happiest, the data showed. "Each additional happy person makes you happier," Christakis said. And happiness is more infectious than unhappiness, they discovered. If a social contact is happy, it increases the possibility that you are happy by 15 percent. A friend of a friend, or the friend of a spouse or a sibling  , if they are happy, increases your chances by 10 percent. A happy third-degree friend -- the friend of a friend of a friend -- increases a person's chances of being happy by 6 percent. But every extra unhappy friend increases the possibility that you'll be unhappy by only 7 percent. The finding is interesting and useful. Among other benefits, happiness has been shown to have an important effect on reduced death rate, pain reduction, and improved heart function. So better understanding of how happiness spreads can help us learn how to promote a healthier society. Other data suggested having extra $5,000 increases a person's chances of becoming happier by about 2 percent. A happy friend is worth about $40,000. According to the research, if you want to be happy, you'd better have more   _  .
neighbor communication social connections siblings' support s' relations