 Cross-cultural studies of stuttering prevalence were very active in early and mid-20th century, particularly under the influence of the works of Wendell Johnson, who claimed that the onset of stuttering was connected to the cultural expectations and the pressure put on young children by anxious parents.Johnson claimed there were cultures where stuttering, and even the word "stutterer", were absent (for example, among some tribes of American Indians).Later studies found that this claim was not supported by the facts, so the influence of cultural factors in stuttering research declined.