17 February 2006
So, there! TV does not rot kids' brains, and it may even help them grow!
The key point for Gentzkow and Shapiro's study is that depending on where you lived and when you were born, the total amount of TV you watched in your childhood could differ vastly. A kid born in 1947 who grew up in Denver, where the first TV station didn't get under way until 1952, would probably not have watched much TV at all until the age of 5. But a kid born the same year in Seattle, where TV began broadcasting in 1948, could watch from the age of 1. If TV-watching during the early years damages kids' brains, then the test scores of Denver high-school seniors in 1965 (the kids born in 1947) should be better than those of 1965 high-school seniors in Seattle.
What if you're concerned about differences between the populations of the two cities that could affect the results? Then you compare test scores within the same city for kids born at different times. Denver kids who were in sixth grade in 1965 would have spent their whole lives with television; their 12th-grade counterparts wouldn't have. If TV matters, the test scores of these two groups should differ, too. Think analogously about lead poisoning. Lead has been scientifically proven to damage kids' brains. If, hypothetically, Seattle added lead to its water in 1948 and Denver did so in 1952, you would see a difference in the test-score data when the kids got to high school—the Seattle kids would score lower than the Denver kids, and the younger Denver kids would score lower than the older Denver ones, because they would have started ingesting lead at a younger age.
From the 1966 Coleman Report, the landmark study of educational opportunity commissioned by the Civil Rights Act of 1964, Gentzkow and Shapiro got 1965 test-score data for almost 300,000 kids. They looked for evidence that greater exposure to television lowered test scores. They found none. After controlling for socioeconomic status, there were no significant test-score differences between kids who lived in cities that got TV earlier as opposed to later, or between kids of pre- and post-TV-age cohorts. Nor did the kids differ significantly in the amount of homework they did, dropout rates, or the wages they eventually made. If anything, the data revealed a small positive uptick in test scores for kids who got to watch more television when they were young. For kids living in households in which English was a second language, or with a mother who had less than a high-school education, the study found that TV had a more sizable positive impact on test scores in reading and general knowledge. Evidently, Bozo the Clown was better than we remember.