Likewise, Émile Durkheim was one of the earliest to suggest that gods represent an extension of human social life to include supernatural beings. In line with this reasoning, psychologist Matt Rossano contends that when humans began living in larger groups, they may have created gods as a means of enforcing morality. In small groups, morality can be enforced by social forces such as gossip or reputation. However, it is much harder to enforce morality using social forces in much larger groups. Rossano indicates that by including ever-watchful gods and spirits, humans discovered an effective strategy for restraining selfishness and building more cooperative groups.