Background: Previous research has presented varying perspectives on the potential effect of screen media use among preschoolers. In this study, we systematically reviewed experimental studies that investigated how pacing and fantasy features of TV programs affect children's attention and executive functions (EFs). Methods: A systematic search was conducted across eight online databases to identify pertinent studies published until August 2023. We followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Results: Fifteen papers involving 1855 participants aged 2–7 years fulfilled all the inclusion criteria for this review and were entered into the narrative synthesis. Despite the challenge of reaching general conclusions and encountering conflicting outcomes, a nuanced analysis reveals distinct patterns within various subgroups. The impact of pacing on attention is discernible, particularly in bottom-up attention processes, although the nature of this effect remains contradictory. Conversely, consistent findings emerge regarding top-down attention, suggesting any impact. Moreover, a subgroup analysis of different EF components yields valuable insights, highlighting the negative effect of fantasy on inhibitory control within the EF framework. Conclusion: The complexity of these outcomes highlights the need for further research, considering factors such as content, child-specific characteristics, environmental factors, and methodological approaches. These findings collectively emphasize the necessity of conducting more comprehensive and detailed research, especially in terms of the underlying mechanisms and their impact on brain function.

There is growing evidence that prevalence rates of autism spectrum disorder (ASD) are increasing. A number of factors appear to contribute to this increase, including excessive screen time. Screen time seems to be linked to the severity of the symptoms of ASD. Given this, the aim of the present cross-sectional study was to investigate the association between early screen time and ASD symptoms severity in the first 36 months of life. To this end, sixty-eight Iranian toddlers (mean age: 27.09 months; 22.1% females) with ASD were recruited. Parents completed the modified checklist for autism in toddlers (M-CHAT), the Repetitive Behavior Scale-Revised (RBS-R), and a lifestyle checklist. Next, parents rated children’s daily exposure to content specifically designed (foreground media) and not specifically designed (background media) for children, along with their daily exposure to social interaction. Per day, toddlers spent 5.12 h (±3.77) with foreground media, 3.72 h (±3.57) with background media, and 2.89 h (±2.74) in interaction with other people (parents). To test the hypotheses, we performed a series of Pearson’s correlations and multiple regression analyses. Toddlers’ higher severity scores for ASD symptoms were associated with longer foreground (r = 0.234, p = 0.001) and longer background (r = 0.180, p = 0.012) media duration, and with shorter duration of interaction with others (r = 0.192, p = 0.009). Toddlers spending 1 h more in foreground screen time and background screen time have 0.38 and 0.29 more units in the ASD symptom severity scale, respectively, while toddlers spending 1 h more in social interactions have 0.42 fewer units in the ASD symptom severity scale. The screen time and interaction duration are related to ASD symptoms severity of toddlers. The cross-sectional study design precludes causal associations, although bi-directional relationships appear plausible.

The structural and functional brain characteristics associated with the excessive use of the internet have attracted substantial research attention in the past decade. In current study, we used voxel-based morphometry (VBM) and multiple regression analysis to assess the relationship between internet addiction tendency (IAT) score and regional gray and white matter volumes (rGMVs and rWMVs) and brain activity during a WM task in a large sample of healthy young adults (n = 1,154, mean age, 20.71 ± 1.78 years). We found a significant positive correlation between IAT score and gray matter volume (GMV) of right supramarginal gyrus (rSMG) and significant negative correlations with white matter volume (WMV) of right temporal lobe (sub-gyral and superior temporal gyrus), right sublobar area (extra-nuclear and lentiform nucleus), right cerebellar anterior lobe, cerebellar tonsil, right frontal lobe (inferior frontal gyrus and sub-gyral areas), and the pons. Also, IAT was significantly and positively correlated with brain activity in the default-mode network (DMN), medial frontal gyrus, medial part of the superior frontal gyrus, and anterior cingulate cortex during a 2-back working memory (WM) task. Moreover, whole-brain analyses of rGMV showed significant effects of interaction between sex and the IAT scores in the area spreading around the left anterior insula and left lentiform. This interaction was moderated by positive correlation in women. These results indicate that IAT is associated with (a) increased GMV in rSMG, which is involved in phonological processing, (b) decreased WMV in areas of frontal, sublobar, and temporal lobes, which are involved in response inhibition, and (c) reduced task-induced deactivation of the DMN, indicative of altered attentional allocation.

The inhibitory control (IC) is one of the basic executive functions (EFs) that all other EFs are hierarchically perched on this ability. Current knowledge of IC development in the elementary school years is limited. In this study, three tasks; go/no-go task (response inhibition), flanker task (attentional inhibition), and circle-tracing time task (motor inhibition) were administered to investigate sex and age-related differences in IC in 240 children (120 boys) aged 7–12 yearspreschoolers. Results showed some gender differences in neutral reaction time (RT) in flanker task and go accuracy number in go/no-go task. Also, results suggest the existence of age-related differences in go accuracy number and RT in go/no-go task, neutral RT in flanker task, and motor inhibition index in circle-tracing task that these correlations follow a nonlinear relationship. Our study indicates that IC develop rapidly in the first two years of formal schooling then proceeds at a slower rate.