Infant video viewing and salivary cortisol responses: a randomized experiment.

OBJECTIVE: To test the hypothesis that salivary cortisol levels respond differently when infants play with blocks compared with watching a digital video disk (DVD). STUDY DESIGN: We conducted a randomized experiment in which 8- to 14-month-old infants either watched a DVD or played with blocks for 30 minutes. Serial salivary cortisol measurements were obtained and analyzed, and parental and infant responses and activities were recorded. Results were converted to standardized effect sizes (ESs) for clarity of presentation. RESULTS: A total of 49 infants (49% female, mean age 10.6 months) participated in the study. In linear regression analyses, there was a trend toward higher cortisol levels in the block group at the 35-minute collection point (ES = 0.47, P = .08) and significantly higher levels at 45 minutes (ES = 0.56, P = .04); these salivary cortisol levels reflect serum levels approximately 10 and 20 minutes into the activity period, respectively. The results were substantially the same in sensitivity analyses excluding the outliers. CONCLUSION: Viewing by infants of a DVD leads to different neuroendocrine responses than block play in a laboratory setting. The implications of these differences are currently unknown, but may suggest different means of cognitive engagement between interactive play and DVD viewing.

Modifying media content for preschool children: a randomized controlled trial.

BACKGROUND: Although previous studies have revealed that preschool-aged children imitate both aggression and prosocial behaviors on screen, there have been few population-based studies designed to reduce aggression in preschool-aged children by modifying what they watch. METHODS: We devised a media diet intervention wherein parents were assisted in substituting high quality prosocial and educational programming for aggression-laden programming without trying to reduce total screen time. We conducted a randomized controlled trial of 565 parents of preschool-aged children ages 3 to 5 years recruited from community pediatric practices. Outcomes were derived from the Social Competence and Behavior Evaluation at 6 and 12 months. RESULTS: At 6 months, the overall mean Social Competence and Behavior Evaluation score was 2.11 points better (95% confidence interval [CI]: 0.78-3.44) in the intervention group as compared with the controls, and similar effects were observed for the externalizing subscale (0.68 [95% CI: 0.06-1.30]) and the social competence subscale (1.04 [95% CI: 0.34-1.74]). The effect for the internalizing subscale was in a positive direction but was not statistically significant (0.42 [95% CI: -0.14 to 0.99]). Although the effect sizes did not noticeably decay at 12 months, the effect on the externalizing subscale was no longer statistically significant (P = .05). In a stratified analysis of the effect on the overall scores, low-income boys appeared to derive the greatest benefit (6.48 [95% CI: 1.60-11.37]). CONCLUSIONS: An intervention to reduce exposure to screen violence and increase exposure to prosocial programming can positively impact child behavior.

Media use and child sleep: the impact of content, timing, and environment.

BACKGROUND: Media use has been shown to negatively affect a child's sleep, especially in the context of evening use or with a television in the child's bedroom. However, little is known about how content choices and adult co-use affect this relationship. OBJECTIVE: To describe the impact of media content, timing, and use behaviors on child sleep. METHODS: These data were collected in the baseline survey and media diary of a randomized controlled trial on media use in children aged 3 to 5 years. Sleep measures were derived from the Children's Sleep Habits Questionnaire. Media diaries captured time, content title, and co-use of television, video-game, and computer usage; titles were coded for ratings, violence, scariness, and pacing. Nested linear regression models were built to examine the impact of timing, content, and co-use on the sleep problem score. RESULTS: On average, children consumed 72.9 minutes of media screen time daily, with 14.1 minutes occurring after 7:00 pm. Eighteen percent of parents reported at least 1 sleep problem; children with a bedroom television consumed more media and were more likely to have a sleep problem. In regression models, each additional hour of evening media use was associated with a significant increase in the sleep problem score (0.743 [95% confidence interval: 0.373-1.114]), as was daytime use with violent content (0.398 [95% confidence interval: 0.121-0.676]). There was a trend toward greater impact of daytime violent use in the context of a bedroom television (P=.098) and in low-income children (P=.07). CONCLUSIONS: Violent content and evening media use were associated with increased sleep problems. However, no such effects were observed with nonviolent daytime media use.