Surveys show that 25 to 30 percent of American parents routinely let their children sleep with them, either for part or all of the night. The United States is one of the very few countries which have a cultural bias against parents sharing a bed with their children. This is not based upon any scientific evidence but rather occurred when in the twentieth century child-care experts began warning parents that they must teach their children to sleep alone or they would create deep psychological scars. However, in most other countries the tradition of children sleeping with parents continues and no deep psychological scars are evidenced. Japan is an example of such a country.
Japan emphasizes the nurturing aspects of family life.
Independence was prized and seen as a virtue. For a child to appear too dependent was unhealthy. The issue of independence is often linked to co-sleeping. United States culture has a reverence for independence. Many people in this society believe that the sooner it is achieved the better.