Variability and patterns in children's media use and links with language development.

AIM: Media use is widespread and rising, but how often and for what purpose young children use media varies, which has differential impacts on development. Yet little work has measured how and why children under 36 months use digital media or media's consequences for language. METHODS: The current study measures how and why 17- to 30-month-old children use digital media and associations with their language abilities. The amount of use, type of activity and caregiver reasons for children's media use were then compared to the child's vocabulary and mean length of utterance. RESULTS: About 17- to 30-month-old children are primarily exposed to TV/videos over other media forms, which are often used to occupy children. Video time (but not other activities) negatively predicts children's language. The negative impact of videos on vocabulary persists regardless of the reason for use, however, the effect of videos on expressive language may be tempered when videos are used for education or connecting. CONCLUSION: Children under 36 months are using digital media at high rates. What they are doing and why they use media is critical to predict the effect it might have on language development. Further research and anticipatory guidance on the consequences of videos are needed.

A longitudinal study of the relationship between children's exposure to screen media and vocabulary development.

AIM: This study addresses the scarcity of longitudinal research on the influence of screen media on children. It aims to explore the longitudinal relationship between children's vocabulary development and their exposure to screen media. METHODS: The study, initiated in 2017, included 72 children (37 boys) in Östergötland, Sweden, at three key developmental stages: preverbal (9.7 months), early verbal (25.5 months) and preliterate (5.4 years). Parents completed online surveys at each time point, reporting their child's screen time. At 10 months and 2 years, age-appropriate vocabulary assessments were conducted online. At age 5, children's vocabulary was laboratory assessed. RESULTS: Correlational analysis revealed a negative relationship between language scores and screen media use across all time points. Furthermore, a cross-lagged panel model demonstrated that screen media use showed significant continuity over time, with screen use at age 2 predicting language development at ages 2 and 5. CONCLUSION: This longitudinal study, spanned from 9 months to 5 years of age, established a predictive negative association between children's exposure to screen media and their vocabulary development. These findings underscore the need to consider the impact of screen media on early childhood development and may inform guidelines for screen media use in young children.

Podocyte protease activated receptor 1 stimulation in mice produces focal segmental glomerulosclerosis mirroring human disease signaling events.

About 30% of patients who have a kidney transplant with underlying nephrotic syndrome (NS) experience rapid relapse of disease in their new graft. This is speculated to be due to a host-derived circulating factor acting on podocytes, the target cells in the kidney, leading to focal segmental glomerulosclerosis (FSGS). Our previous work suggests that podocyte membrane protease receptor 1 (PAR-1) is activated by a circulating factor in relapsing FSGS. Here, the role of PAR-1 was studied in human podocytes in vitro, and using a mouse model with developmental or inducible expression of podocyte-specific constitutively active PAR-1, and using biopsies from patients with nephrotic syndrome. In vitro podocyte PAR-1 activation caused a pro-migratory phenotype with phosphorylation of the kinase JNK, VASP protein and docking protein Paxillin. This signaling was mirrored in podocytes exposed to patient relapse-derived NS plasma and in patient disease biopsies. Both developmental and inducible activation of transgenic PAR-1 (NPHS2 Cre PAR-1Active+/-) caused early severe nephrotic syndrome, FSGS, kidney failure and, in the developmental model, premature death. We found that the non-selective cation channel protein TRPC6 could be a key modulator of PAR-1 signaling and TRPC6 knockout in our mouse model significantly improved proteinuria and extended lifespan. Thus, our work implicates podocyte PAR-1 activation as a key initiator of human NS circulating factor and that the PAR-1 signaling effects were partly modulated through TRPC6.

Preschooler screen time and temperamental anger/frustration during the COVID-19 pandemic.

BACKGROUND: In the context of increased media use and family distress during the pandemic, we examine whether preschooler screen time at age 3.5 contributes to later expressions of anger/frustration at 4.5, while also considering the inverse association. METHODS: Data are from a cohort of 315 Canadian preschool-aged children during the COVID-19 pandemic. Parent-reported measures included child h/day of screen time and child temperamental anger/frustration, both measured at 3.5 and 4.5 years of age. Indicators of family distress include use of childcare and child sleep, family income, parenting stress, and parent education, marital and employment status. We also consider child sex as a control variable. RESULTS: A crossed-lagged panel model revealed continuity in screen time between the ages of 3.5 and 4.5 (ß = 0.68) and temperamental anger/frustration from 3.5 to 4.5 (ß = 0.60). Child screen time at age 3.5 predicted increased proneness to anger/frustration at age 4.5 (ß = 0.14). Anger/frustration at age 3.5 did not predict screen time at age 4.5. CONCLUSION: Our results suggest that preschooler screen time during the pandemic may have undermined the ability to regulate negative emotions, a key component of social and academic competence. Supporting parents in implementing healthy media habits post pandemic may benefit young children's development. IMPACT: Key message: this study observes prospective bidirectional associations between preschoolers screen time and temperamental displays of anger or frustration during the COVID-19 pandemic. What does it add: we provide evidence that preschool screen time at age 3.5 prospectively contributes to the tendency to react in anger/frustration at age 4.5. In contrast, greater proneness to anger/frustration did not predict later exposure to screen time. What is the impact: health practitioners should enquire about media use habits during well-child visits to foster children's healthy development during the preschool years.

Sleep-dependent memory consolidation of televised content in infants.

Infants face the constant challenge of selecting information for encoding and storage from a continuous incoming stream of data. Sleep might help in this process by selectively consolidating new memory traces that are likely to be of future relevance. Using a deferred imitation paradigm and an experimental design, we asked whether 15- and 24-month-old infants (N = 105) who slept soon after encoding a televised demonstration of target actions would show higher imitation scores (retention) after a 24-h delay than same-aged infants who stayed awake for ≥4 h after encoding. In light of infants' well-known difficulties in learning and remembering information from screens, we tested if increasing the relevance of the televised content via standardised caregiver verbalisations might yield the highest imitation scores in the sleep condition. Regardless of sleep condition, 24-month-olds exhibited retention of target actions while 15-month-olds consistently failed to do so. For 24-month-olds, temporal recall was facilitated by sleep, but not by parental verbalisations. Correlational analyses revealed that more time asleep within 4 h after encoding was associated with better retention of the target actions and their temporal order in 24-months-olds. These results suggest that sleep facilitates memory consolidation of screen-based content in late infancy and that this effect might not hinge on caregivers' verbal engagement during viewing.

The development of the object sequencing imitation task to measure working memory in preschoolers.

We developed a new object sequencing imitation (OSI) task for preschoolers. We parameterized the task to test the effects of working memory load in 56 3- to 5-year-old children in a museum. We tested individual groups of 3-, 4-, and 5-year-olds on both "low" (2- to 4-step) and "high" (3- to 5-step) memory load sequences on two variants of the task. The experimenter demonstrated each sequence three times, and children were given 3 trials to imitate the sequence, receiving feedback from the experimenter following each trial. Children were tested on an object that was functionally the same but perceptually different. All preschoolers performed significantly above baseline. We found a significant load effect, showing that performance decreased with increasing steps per sequence. There was no effect of age on performance, showing that leveling of the task across age was successful. Overall, the newly developed OSI task can test age- and load-related changes in working memory in 3- to 5-year-old children. The new OSI task will have utility in longitudinal studies and in studies where multiple trials are needed such as neuroimaging.

Qualitative and quantitative aspects of child-directed parental talk and the relation to 2-year-old's developing vocabulary.

Although prior research has independently linked vocabulary development with toddlers' media usage, parental mental state talk (MST), and parent-child conversational turn-taking (CTT), these variables have not been investigated within the same study. In this study, we focus on associations between these variables and 2-year-old's (N = 87) vocabulary. Child vocabulary and digital media use were measured through online questionnaires. We took a multimethod approach to measure parents' child-directed talk. First, we used a home sound environment recording (Language ENvironment Analysis technology) to estimate parents' talk (CTT). Second, parents narrated a picture book, the Frog story, to assess the parent's MST. There was a negative association between how much children watched video content and their vocabulary. However, parents reported that they frequently co-viewed and engaged with the child and media. The negative association first displayed between the amount of video content viewed and the child's developing vocabulary was fully mediated by the parents' qualitative and quantitative talk as measured by MST and CCT, respectively. We propose that the parent relative level of MST and CTT also occurs when parents engage with the child during media use.

Presence at a distance: Video chat supports intergenerational sensitivity and positive infant affect during COVID-19.

COVID-19 disrupted infant contact with people beyond the immediate family. Because grandparents faced higher COVID-19 risks due to age, many used video chat instead of interacting with their infant grandchildren in person. We conducted a semi-naturalistic, longitudinal study with 48 families, each of whom submitted a series of video chats and surveys, and most (n = 40) also submitted a video of an in-person interaction. Families were mostly highly-educated, White/Caucasian, and lived between 1 and 2700 miles apart. We used multilevel models to examine grandparents' and parents' sensitivity during video chat across time (centered at February 1, 2021, the approximate date of vaccine availability). Grandparent video chat sensitivity changed as a function of date and parent sensitivity. Parent sensitivity changed as a function of date, grandparent sensitivity, and geographic distance. We then modeled infants' affective valence during video chat and in-person interactions with their grandparents, which was only predicted by grandparent sensitivity, not modality or other factors. This study demonstrates that caregivers were sensitive toward infants during video chat interactions despite fluctuations in family stress and reduced in-person contact during COVID-19 and that grandparent sensitivity predicted positive infant affect during both video chat and in-person interactions.

Background media use is negatively related to language and literacy skills: indirect effects of self-regulation.

BACKGROUND: Media use is pervasive among young children. Over 95% of homes in the US have one or more televisions, and access to screen-based media continues to grow with the availability of new technologies. Broadly, exposure to large amounts of screen-based media is negatively related to language and literacy skills; however, questions remain as to the features of media that are detrimental to these skills and the mechanisms by which they are connected. METHODS: A nationally representative sample of 922 children aged 3-7 years was recruited. Parents completed phone-based questionnaires of children's language, literacy, and self-regulation skills and a 24-h time diary in 2009. Path models were used to estimate the direct and indirect associations between context and content of media use with language and literacy skills. RESULTS: Background and entertainment television, but not educational television, were negatively associated with language and literacy. Further, the link between background television and language and literacy skills was fully mediated by self-regulation. CONCLUSIONS: Television left on in the background and entertainment programming (or that which is not child-directed) is particularly detrimental for language and literacy skills. Additional research is needed to further explore self-regulation as a mechanism by which screen use predicts academic skills. IMPACT: Background and entertainment television are negatively associated with language and literacy skills in 3- to 7-year-old children. We find no relation between educational programming and language and literacy skills. Self-regulation is a potential mechanism underlying the relation between background television and language and literacy skills. Anticipatory guidance for parents would be to consider turning off screen-based media devices when no one is watching. Parents should be mindful of the types of content their children are watching on screen-based media.

Optimizing imitation: Examining cognitive factors leading to imitation, overimitation, and goal emulation in preschoolers.

Humans imitate patently irrelevant actions known as overimitation, and rather than decreasing with age, overimitation increases with age. Whereas most overimitation research has focused on social factors associated with overimitation, comparatively little is known about the cognitive- and task-specific features that influence overimitation. Specifically, developmental contrasts between imitation and overimitation are confounded by the addition of irrelevant actions to causally necessary actions, increasing sequence length, cognitive load, and processing costs-variables known to be age dependent. We constructed a novel puzzle box task such that a four-step imitation, four-step overimitation, and two-step efficient sequence could be demonstrated using the same apparatus on video. In Experiments 1 and 2, 2.5- to 5-year-olds randomly assigned to imitation and overimitation groups performed significantly more target actions than baseline control groups. Rates of imitation and overimitation increased as a function of age, with older preschoolers outperforming younger preschoolers in both conditions. In Experiment 3, preschoolers were shown a video of an efficient two-step demonstration prior to testing. After they responded, they were shown a four-step overimitation video and were tested on the same puzzle box. Children imitated the efficient demonstration, but after watching the overimitation video, they also overimitated the irrelevant actions. Once again, older children overimitated more than younger children. Together, results show that preschoolers are faithful, flexible, and persistent overimitators. The fidelity and flexibility of overimitation are constrained not only by social factors but also by basic cognitive processes that vary across age groups. As these constraints diminish, overimitation and flexible (optimal) imitation increases.

Applying computational modeling to assess age-, sex-, and strategy-related differences in Spin the Pots, a working memory task for 2- to 4-year-olds.

Working memory (WM) develops rapidly during early childhood. In the present study, visual WM (VSM) was measured using the well-established Spin the Pots task (Hughes & Ensor, 2005), a complex non-verbal eight-location object occlusion task. A self-ordered hiding procedure was adopted to allow for an examination of children's strategy use during a VWM task. Participants (N = 640) between the ages of 2 and 4 years were tested under semi-naturalistic conditions, in the home or in a museum. Computational modeling was used to estimate an expected value for the total trials to complete Spin the Pots via a random search and child performance was compared to expected values. Based on this approach, we determined that children who found six stickers retrieved them in significantly fewer trials than the expected value, excluding chance performance and implicating VWM. Results also showed age-related and sex-related changes in VWM. Between 2 and 4 years of age, 4-year-olds performed significantly better than younger children and girls out-performed the boys. Spontaneous use of a color matching hiding strategy was associated with a higher success rate on the task. Implications of these findings for early development of VWM are discussed.

Patterns of mutual exclusivity and retention: A study of monolingual and bilingual 2-year-olds.

When children learn their native language, they tend to treat objects as if they only have one label-a principle known as mutual exclusivity. However, bilingual children are faced with a different cognitive challenge-they need to learn to associate two labels with one object. In the present study, we compared bilingual and monolingual 24-month-olds' performance on a challenging and semi-naturalistic forced-choice referent selection task and retention test. Overall, both language groups performed similarly on referent selection but differed on retention. Specifically, while monolingual infants showed some retention, bilingual infants performed at chance and significantly worse than their monolingual peers.

The development of gaze following in monolingual and bilingual infants: A multi-laboratory study.

Determining the meanings of words requires language learners to attend to what other people say. However, it behooves a young language learner to simultaneously encode relevant non-verbal cues, for example, by following the direction of their eye gaze. Sensitivity to cues such as eye gaze might be particularly important for bilingual infants, as they encounter less consistency between words and objects than monolingual infants, and do not always have access to the same word-learning heuristics (e.g., mutual exclusivity). In a preregistered study, we tested the hypothesis that bilingual experience would lead to a more pronounced ability to follow another's gaze. We used a gaze-following paradigm developed by Senju and Csibra (Current Biology, 18, 2008, 668) to test a total of 93 6- to 9-month-old and 229 12- to 15-month-old monolingual and bilingual infants, in 11 laboratories located in 8 countries. Monolingual and bilingual infants showed similar gaze-following abilities, and both groups showed age-related improvements in speed, accuracy, frequency, and duration of fixations to congruent objects. Unexpectedly, bilinguals tended to make more frequent fixations to on-screen objects, whether or not they were cued by the actor. These results suggest that gaze sensitivity is a fundamental aspect of development that is robust to variation in language exposure.

Actions speak louder than words: Differences in memory flexibility between monolingual and bilingual 18-month-olds.

Bilingual infants from 6- to 24-months of age are more likely to generalize, flexibly reproducing actions on novel objects significantly more often than age-matched monolingual infants are. In the current study, we examine whether the addition of novel verbal labels enhances memory generalization in a perceptually complex imitation task. We hypothesized that labels would provide an additional retrieval cue and aid memory generalization for bilingual infants. Specifically, we hypothesized that bilinguals might be more likely than monolinguals to map multiple perceptual features onto a novel label and therefore show enhanced generalization. Eighty-seven 18-month-old monolingual and bilingual infants were randomly assigned to one of two experimental conditions or a baseline control condition. In the experimental conditions, either no label or a novel label was added during demonstration and again at the beginning of the test session. After a 24-hr delay, infants were tested with the same stimulus set to test cued recall and with a perceptually different but functionally equivalent stimulus set to test memory generalization. Bilinguals performed significantly above baseline on both cued recall and memory generalization in both experimental conditions, whereas monolinguals performed significantly above baseline only on cued recall in both experimental conditions. These findings show a difference between monolinguals and bilinguals in memory generalization and suggest that generalization differences between groups may arise from visual perceptual processing rather than linguistic processing. A video abstract of this article can be viewed at https://youtu.be/yXB4pM3fF2k.

Procedural memory in infancy: Evidence from implicit sequence learning in an eye-tracking paradigm.

Procedural memory underpins the learning of skills and habits. It is often tested in children and adults with sequence learning on the serial reaction time (SRT) task, which involves manual motor control. However, due to infants' slowly developing control of motor actions, most procedures that require motor control cannot be examined in infancy. Here, we investigated procedural memory using an SRT task adapted for infants. During the task, images appeared at one of three locations on a screen, with the location order following a five-item recurring sequence. Three blocks of recurring sequences were followed by a random-order fourth block and finally another block of recurring sequences. Eye movement data were collected for infants (n = 35) and adults (n = 31). Reaction time was indexed by calculating the saccade latencies for orienting to each image as it appeared. The entire protocol took less than 3 min. Sequence learning in the SRT task can be operationalized as an increase in latencies in the random block as compared with the preceding and following sequence blocks. This pattern was observed in both the infants and adults. This study is the first to report learning in an SRT task in infants as young as 9  months. This SRT protocol is a promising procedure for measuring procedural memory in infants.

Only domain-specific imitation practice makes imitation perfect.

Does imitation involve specialized mechanisms or general-unspecialized-learning processes? To address this question, preschoolers (3- and 4-year-olds) were assigned to one of four "practice" groups. Before and after the practice phases, each group was tested on a novel Spatial Imitation sequence. During the practice phase, children in the Spatial Imitation group practiced jointly attending, vicariously encoding, and copying the novel spatial sequences. In the Item Imitation group, children practiced jointly attending, vicariously encoding, and copying novel item sequences. In the Trial-and-Error group, children practiced encoding and recalling a series of novel spatial sequences entirely through individual (operant) learning. In the Free Play (no practice) control group, children played a touchscreen drawing game that controlled for practice time on the touchscreen and mirrored some of the same actions and responses used in the experimental conditions. Results of the difference between pre- and post-practice effects on novel spatial imitation sequences showed that only the Spatial Imitation practice group significantly improved relative to the Free Play group. Individual Spatial Trial-and-Error practice did not significantly improve spatial imitation. The effect of Item Imitation practice was intermediate. These results are inconsistent with the hypothesis that general processes alone--or primarily--support imitation learning and is more consistent with a mosaic model that posits an additive-interaction-effect on imitation performance where a more general social cognitive mechanism (i.e., natural pedagogy) gathers the relevant information from the demonstration and another more specialized mechanism (i.e., imitation specific) transforms that information into a matching response.

Look At That! Video Chat and Joint Visual Attention Development Among Babies and Toddlers.

Although many relatives use video chat to keep in touch with toddlers, key features of adult-toddler interaction like joint visual attention (JVA) may be compromised in this context. In this study, 25 families with a child between 6 and 24 months were observed using video chat at home with geographically separated grandparents. We define two types of screen-mediated JVA (across- and within-screen) and report age-related increases in the babies' across-screen JVA initiations, and that family JVA usage was positively related to babies' overall attention during video calls. Babies today are immersed in a digital world where formative relationships are often mediated by a screen. Implications for both infant social development and developmental research are discussed.

The Ghost in the Touchscreen: Social Scaffolds Promote Learning by Toddlers.

This study examined the effect of a "ghost" demonstration on toddlers' imitation. In the ghost condition, virtual pieces moved to make a fish or boat puzzle. Fifty-two 2.5- and 3-year-olds were tested on a touchscreen (no transfer) or with 3D pieces (transfer); children tested with 3D pieces scored above a no demonstration baseline, but children tested on the touchscreen did not. Practice on the touchscreen (n = 23) by 2.5- and 3-year-olds prior to the ghost demonstration did not improve performance. Finally, children who learned the puzzle task via a social demonstration and were tested on the touchscreen (n = 26) performed better than the ghost conditions. Taken together, these studies demonstrate that social demonstrations enhance learning from novel touchscreen tools during early childhood.