Since finishing ADHD and the Nature of Self Control, I hadn't found any new and interesting articles to describe until today. This is an article in Pediatrics: a monthly peer-reviewed journal for Pediatricians. Previous research has seemed to indicate that more television-watching by children leads to more attention problems. The evidence, however, is mostly observational and does not indicate exactly how attention is affected by television.
The authors of this study thought that the problem could be the fast pace of images in many TV shows. When we see something for only a short time before it is replaced by something else, our brain spends its energy identifying what it sees each time. This takes place in the sensory part of our brain, not in the pre-frontal cortex, where the brain prioritizes our attention with executive function. If this is the way that the rapid change of scenes on TV caused attention problems, then executive function should be worse after watching them than after doing something else.
To test their theory, they recruited sixty 4-year-old children and divided them into three groups each of which was assigned to a different activity for 9 minutes. The first group watched a cartoon about "an animated sponge" with complete scene changes every 11 seconds. The second group also watched a TV show, but this one was from PBS and changed scenes every 34 seconds. The third group was given paper, crayons and markers and told to draw freely.
Each child pursued their activity in a separate room and after the time was up, the researcher tested their executive function. They used standard activities which measure verbal and non-verbal working memory, spatial planning and delay-of-gratification.
The result was that the group which watched the fast paced cartoon scored significantly worse than either of the other groups. I was surprised that those who watched the PBS show scored better than those who colored on two of the tests, but it is good news for those of us who support Public Television for kids!
This study gives new information about the effect of different activities on the 4-year-old brain. At least at this age, exposure to rapidly changing sensations interferes with the ability to process more complicated information. It would be interesting to see the results of a similar study on adults with and without ADHD... I think that similar effects might be shown and would be more pronounced if ADHD were present.