In the 20th century folklore studies expanded to include urban communities and diverse groups, shifting focus from the origins of present meaning and function to considering change within tradition as noncorruptive. Emphasis shifted from the past to the present, from the search for origins to the investigation of present meaning and function. Also appearing in folklore studies in the mid-20th century was the concept of urban legend—stories about an unusual or humorous event that many people believe to be true but is not.