Children's television viewing and cognitive outcomes: a longitudinal analysis of national data.

Objective: To test the independent effects of television viewing in children before age 3 years and at ages 3 to 5 years on several measures of cognitive outcomes at ages 6 and 7 years.

Design: Using data from a nationally representative data set, we regressed 4 measures of cognitive development at ages 6 and 7 years on television viewing before age 3 years and at ages 3 to 5 years, controlling for parental cognitive stimulation throughout early childhood, maternal education, and IQ.

Results: Before age 3 years, the children in this study watched an average of 2.2 hours per day; at ages 3 to 5 years, the daily average was 3.3 hours. Adjusted for the covariates mentioned earlier, each hour of average daily television viewing before age 3 years was associated with deleterious effects on the Peabody Individual Achievement Test Reading Recognition Scale of 0.31 points (95% confidence interval [CI], -0.61 to -0.01 points), on the Peabody Individual Achievement Test Reading Comprehension Scale of 0.58 points (95% CI, -0.94 to -0.21 points), and on the Memory for Digit Span assessment from the Wechsler Intelligence Scales for Children of -0.10 points (95% CI, -0.20 to 0 points). For the Reading Recognition Scale score only, a beneficial effect of television at ages 3 to 5 years was identified, with each hour associated with a 0.51-point improvement in the score (95% CI, 0.17 to 0.85 points).

Conclusions: There are modest adverse effects of television viewing before age 3 years on the subsequent cognitive development of children. These results suggest that greater adherence to the American Academy of Pediatrics guidelines that children younger than 2 years not watch television is warranted.