Associations among exposure to television or video, language development, and school achievement in childhood: a prospective birth cohort study

Exposure to electronic media, which begins in early childhood, has been gradually increasing. This study investigated the associations between time watching television or video (TV time), children's language development, and school achievement using a large prospective design.

The participants underwent annual assessment from birth (T1; 5.5 months) to T8 (87.9 months). We used a parental questionnaire to evaluate TV time annually from T3 (2.2 years) to T8 (7.3 years), by the item asking "How many hours does your child usually spend a day watching TV or videos?". Children were grouped by TV time using group-based trajectory analysis. Among 2150 participants, 1087 were included in the final analysis. The Korean version of the Denver II and the Korean-Ages and Stages questionnaires were administered to evaluate early childhood development (T1 to T3). The Receptive and Expressive Vocabulary Test was used to assess children's language development at T8. Questionnaires completed by both parents and teachers were used to evaluate school achievement at T8.

Participants were divided into "Low Descending" (LD), "Medium Flat" (MF), "High Ascending" (HA), and "Extremely High Descending" (XHD) groups. Early language development at T1 and T2 did not significantly differ among all groups. However, language development at T3 and T8, and school achievement at T8 differed significantly, and were the highest in LD and lowest in HA.

We found a negative association between greater TV time and children's language and cognitive development. Thus, unchecked TV exposure could be detrimental to childhood cognitive development.