Objective: The purpose of this work was to conduct a systematic review of experimental trials for the effects of television viewing by infants and preschoolers.
Methods: Searches were conducted as of January 2005 on several online bibliographic databases for the disciplines of medicine, psychology, education, and communications. Relevant bibliographies were also reviewed. The article contents were critically evaluated to determine whether they met inclusion criteria. Data were extracted from each included article regarding study methods and results.
Results: Twelve controlled trials met all of the criteria for inclusion in this review. All of the studies focused on the effect of television content rather than viewing time. The findings suggest that educational television programs are successful in broadening young children's knowledge, affecting their racial attitudes, and increasing their imaginativeness. There is insufficient experimental evidence for effects of viewing these programs on either children's prosocial behavior or their aggressive behavior. Finally, there is some evidence that viewing cartoons has a negative effect on children's attentional abilities.
Conclusions: A number of gaps remain in the literature. Although the amount of time children spend viewing television raises concern, the studies presented here focus only on content. Despite the fact that infants are the fastest growing television market segment, the controlled trials only include children aged > or = 3 years. Finally, the clinical utility of the findings are questionable given that most studies included small group sizes, all took place in nonnaturalistic settings, and all but 1 study only evaluated short-term effects of television viewing.