Quitting Smoking Helps Social Life

A random sample of 1000 subjects in 1971 and 2000. Yellow nodes are smokers (with the node size proportional to number of cigarettes consumed); green nodes are nonsmokers. Orange arrows denote friendship or marital ties; purple arrows, family ties. In 1971, there are many more smokers and they are dispersed throughout the social network. By 2000, there are not only fewer people smoking, but they have also been pushed to the outside of their social groups. Courtesy James Fowler, UC San Diego