“Scientists know group pressure is a powerful influence over health behaviors, including alcohol use, smoking and exercise. By developing a deeper understanding of the dynamics of trend-setters and trend-followers, researchers may discover more behavioral options for promoting health and preventing disease.
…observation of others’ behavior can also result in misperceptions of the norm, which in turn can cause the actual norm to shift. Misperceptions are dangerous when it comes to risky behavior. In a series of studies, Dr. Prentice and her team asked student participants, who filled out questionnaires, how much alcohol they drank, and how much they thought a typical student at their college drank. The researchers found students often overestimated how much others drank. The amount students reported drinking was closely related to their beliefs about how much others drank: Students who thought others drank more tended to report drinking more.”
Read further from The Wall Street Journal (2011)