premise: Well-known theories of child development'Freud 's , Skinner 's , Gesell 's , and Piaget 's , for example'provide little comfort , since dramatic shifts in favored theories have occurred since the launching of systematic study of children about 100 years ago and true is true and true is true and true is true and true is true and true is true .
hypothesis: Freud 's theories of child development is not a well known piece of information .