Study Confirms TV Viewing Deleterious for Very Young Children by Rosemary Frei From Medscape Medical News
June 11, 2009 — Infants vocalize significantly less, and the adults who are with them also speak much less, while they are watching TV, a study published in the June issue of the Archives of Pediatric and Adolescent Medicine has confirmed.
Researchers analyzed digital recordings of 2- to 48-month-old children and their parents that were made once a month on random days for up to 2 years. Each hour of audible television was associated with a significant drop in how much the children vocalized and engaged in conversational exchanges with the adults present.
The adults also spoke 770 fewer words during each hour that the TV was audible — a dramatic bite out of the average 940 word-per-hour rate adults usually speak.
"That 770-word reduction is almost a complete 1-to-1 displacement [of the amount adults talk]," said lead investigator Dimitri Christakis, MD, from the Center for Child Health, Behavior, and Development at the Seattle Children's Research Institute and the University of Washington School of Medicine.
The American Academy of Pediatrics recommends that TV exposure should be avoided in children under the age of 2 years and that older children should view only 2 or fewer hours of TV per day. This is to ensure that children engage in as much interaction as possible with adults and thus have normal language development and brain growth.
A Major Problem
Benard Dreyer, MD, from Bellevue Hospital and the New York University School of Medicine, in New York City, was an author of a previous, retrospective study of low-income families that also showed TV exposure is associated with less parent-child vocal interaction (Mendelsohn AL et al. Arch Pediatr Adolesc Med. 2008;162:411-417). He said he "completely" agrees with the veracity of the new study's findings.
"I think that this [TV watching by young children] is a major problem, especially with respect to language development and all other types of early-childhood development that are predicated on interacting with adults, including cognitive development," Dr. Dreyer told Medscape Psychiatry. "Children who are interacting less with their parents and hearing less language are going to develop less language and also fewer other cognitive skills," he added.
Dr. Christakis and his colleagues obtained the data for the study from the LENA Foundation Natural Language Study. In the study, parents and their children aged 2 to 48 months were recruited and matched to the national-average levels of maternal education and child sex. The parents agreed to put a digital language-processing device in the front pocket of a specially designed vest that their child wore once a month for up to 24 months.
A total of 329 child-parent pairs contributed at least 1 recording with usable speech data to the study. The children's average age at the first session was 18 months, 51% were boys, and 79% were white; they were exposed to a mean of 1.3 hours of audible TV per day.
The investigators performed regression analyses that revealed that television exposure was linked with significantly reduced child vocalization count and duration as well as reduced conversation. These effects increased with every additional hour per day of television exposure.
Likewise, every additional hour of television exposure was associated with a 636-word decrease in the number of words the children heard from the female adults in their vicinity and a 134-word decrease in words heard from adult males, for a total reduction of 770 adult words.