Friday, February 17, 2006


On the subject of television viewing, this study is particularly intriguing:
Does Television Rot Your Brain? New Evidence from the Coleman Study

University of Chicago - Graduate School of Business
University of Chicago; National Bureau of Economic Research (NBER)
January 27, 2006

We use heterogeneity in the timing of television's introduction to different local markets to identify the effect of preschool television exposure on standardized test scores later in life. Our preferred point estimate indicates that an additional year of preschool television exposure raises average test scores by about .02 standard deviations. We are able to reject negative effects larger than about .03 standard deviations per year of television exposure. For reading and general knowledge scores, the positive effects we find are marginally statistically significant, and these effects are largest for children from households where English is not the primary language, for children whose mothers have less than a high school education, and for non-white children. To capture more general effects on human capital, we also study the effect of childhood television exposure on school completion and subsequent labor market earnings, and again find no evidence of a negative effect.
A few scattered thoughts:

1. Nice to see that researchers are still digging out useful findings from the Coleman data (i.e., data on several hundred thousand schoolchildren in 1965, which enabled the researchers to measure TV's effect by comparing children who had been exposed to commercial television for their entire lives vs. children who were older or lived in cities where television was introduced later).

2. That said, television programming was much different before 1965 than it is today. From all that I can tell, the programming then was much calmer and more rational. Whereas today's kids programming (especially the commercials) tends to be a) full of exciting colors, b) teeming with activity (bouncing visuals, ultra-quick changes between different camera shots), c) often accompanied by obnoxiously loud, driving dance/rock music, d) never devoting much time to any single scene (Sesame Street is typical here). My hunch is that in all of these ways, kids programming today is much more likely to encourage hyperactivity, shorten attention spans, etc.

3. 0.02 standard deviations in increased test scores really isn't very much at all.

4. The study explains further that children whose parents weren't likely to read to them benefited a little from television (i.e., television is better than nothing), but where television displaced reading, the children were harmed (although not by much).
We find that non-white students benefit considerably more from television exposure than do white students. The point estimate of the effect on average test scores is more than 0.05 for non-white students, as compared to less than 0.01 for white students. For non-white students, the effect of television on verbal scores is positive and statistically significant, and the effects on reading and general knowledge scores are positive and marginally statistically significant. By contrast, we find statistically significant evidence that white students’ general knowledge test scores are decreased by television exposure.

* * *

For students who were not read to as preschoolers, an additional year of television is estimated to raise average test scores by about 0.09 standard deviations. This coefficient is marginally statistically significant (p = 0.058). Moving to the top of the preschool reading distribution lowers this coefficient by a statistically significant 0.11 standard deviations, implying that students who were read to regularly would have experienced a small and statistically insignificant decline in average test scores as a result of an additional year of television exposure.

* * *

In all cases television is estimated to have a positive effect on students whose parents did not read to them, and in most cases this positive effect is economically nontrivial and statistically significant at the 10 percent level. Also, the interaction between childhood reading and television exposure is consistently negative and nontrivial in size, and is often statistically significant, implying in most cases that the effect of television on students who were read to regularly is small and negative.

These findings provide further support for the hypothesis that children whose home environments were more conducive to learning were more negatively impacted by television.



Post a Comment

Subscribe to Post Comments [Atom]

<< Home