Preschoolers' engagement with screen content and associations with sleep and cognitive development.

Preschool children's exposure to screen media and associations with sleep, language, and cognition were investigated along with the time of day of screen exposure, content type, and whether use occurred with someone. Caregivers of Australian children, aged 2 years, 11 months to 5 years, 11 months, answered questions online about the durations children engaged with entertainment, relaxing/calming, and educational content. Fifty-nine percent of children engaged with relaxing/calming content and 86 % with educational, but all children engaged with entertainment content, which became the focus of the analyses. Average daily durations engaged with relaxing and educational content were 1 h each and 2 h for entertainment content. Longer time spent engaged with entertainment content was associated with shorter sleep duration and poorer sleep quality. The interaction between screen time and usage at night vs. daytime only was non-significant suggesting that the association with sleep duration was similar regardless of time of day of usage. Greater screen time also predicted lower communication and problem solving scores, and more attention difficulties. Engaging in screen content with someone else was associated with poorer problem solving skills, whereas engaging alone was associated with better problem solving. The findings here indicate that preschoolers largely engage in entertainment content and this has implications for their sleep even when screen engagement predominantly occurs during the day. Greater screen time also has implications for cognitive and language development raising questions about the time children spend on screens that could be spent on activities that better support development.

Making heads or tails of body inversion effects: Do heads matter?

Observers are better at discriminating upright bodies than inverted bodies, and this body inversion effect (BIE) is reliable with whole figures (bodies with heads), but not with bodies presented without heads or the heads occluded suggesting that heads may be key to BIEs. Some studies present whole figures and bodies without heads between groups, and BIEs are not found for bodies without heads [1]. Other studies present whole figures and bodies without heads in the same blocks and BIEs are found with bodies without heads [2]. Does seeing the heads of whole figures induce BIEs in bodies without heads? Here, participants discriminated bodies with either whole figures and bodies without heads presented within blocks, or in separate blocks with bodies without heads presented first. We tested body identity and posture discrimination and measured participants' gaze. BIEs were found with whole figures and bodies without heads in both identity and posture discrimination, and in both study designs. However, efficiency scores were better for the whole figures than the bodies without heads, but only when whole figures appeared in separate blocks. The magnitude of the BIE was overall stronger for whole figures compared to bodies without heads, but only in identity discrimination. BIE magnitudes were similar in the identity and posture tasks. Participants were better at identity discrimination, yet, there was greater looking at heads and less at bodies. During posture discrimination, greater looking at bodies and less at heads was associated with better performance. Faces might influence BIEs but are not essential. Configural representations of bodies without heads are sufficient for BIEs in posture and identity discrimination.

Prior Exposure and Toddlers' Sleep-Related Memory for Novel Words.

Children can easily link a novel word to a novel, unnamed object-something referred to as fast mapping. Despite the ease and speed with which children do this, their memories for novel fast-mapped words can be poor unless they receive memory supports such as further exposure to the words or sleep. Axelsson, Swinton, Winiger, and Horst (2018) found that 2.5-year-old children who napped after fast mapping had better retention of novel words than children who did not nap. Retention declined for those who did not nap. The children received no memory supports and determined the word-object mappings independently. Previous studies report enhanced memories after sleeping in children and adults, but the napping children's retention in the Axelsson et al. study remained steady across time. We report a follow-up investigation where memory supports are provided after fast mapping to test whether memories would be enhanced following napping. Children's retention of novel words improved and remained greater than chance; however, there was no nap effect with no significant difference between the children who napped and those who did not. These findings suggest that when memory supports are provided, retention improves, and the word-object mappings remain stable over time. When memory traces are weak and labile, such as after fast mapping, without further memory supports, sleeping soon after helps stabilise and prevent decay of word-object mappings.

Humans' pupillary contagion extends to cats and dogs.

When viewing pupil sizes change, our own pupil sizes change, a phenomenon known as pupillary contagion. This involuntary response is reliable between humans but can be affected by familiarity and empathy. We investigated whether the pupillary contagion response occurs for humans viewing familiar species-cats and dogs-and whether it is modulated by preferences for particular species. Pupil sizes were measured while viewing cat, dog and human images with small, medium and large pupils. Trait empathy, cat and dog affiliation and experience were subsequently measured. There was an image pupil size effect, but this did not vary by species. There was greater pupil size change to cats and dogs than to humans, but this might have been due to the varying size and appearance of the cats and dogs. Greater dog affiliation was also associated with smaller overall pupil size change to dogs and larger change to humans, but this did not interact with image pupil size. Dog affiliation might be associated with less arousal to dog images. In sum, pupillary contagion responses indicate a spontaneous transfer of information about internal states and the findings suggest that humans are sensitive to this across species, regardless of individual preference.

Body Inversion Effects With Photographic Images of Body Postures: Is It About Faces?

As with faces, participants are better at discriminating upright bodies than inverted bodies. This inversion effect is reliable for whole figures, namely, bodies with heads, but it is less reliable for headless bodies. This suggests that removal of the head disrupts typical processing of human figures, and raises questions about the role of faces in efficient body discrimination. In most studies, faces are occluded, but the aim here was to exclude faces in a more ecologically valid way by presenting photographic images of human figures from behind (about-facing), as well as measuring gaze to different parts of the figures. Participants determined whether pairs of sequentially presented body postures were the same or different for whole and headless figures. Presenting about-facing figures (heads seen from behind) and forward-facing figures with faces enabled a comparison of the effect of the presence or absence of faces. Replicating previous findings, there were inversion effects for forward-facing whole figures, but less reliable effects for headless images. There were also inversion effects for about-facing whole figures, but not about-facing headless figures. Accuracy was higher in the forward- compared to the about-facing conditions, but proportional dwell time was greater to bodies in about-facing images. Likewise, despite better discrimination of forward-facing upright compared to inverted whole figures, participants focused more on the heads and less on the bodies in upright compared to inverted images. However, there was no clear relationship between performance and dwell time proportions to heads. Body inversion effects (BIEs) were found with about-facing whole figures and headless forward-facing figures, despite the absence of faces. With inverted whole figures, there was a significant relationship between performance and greater looking at bodies, and less at heads suggesting that in more difficult conditions a focus on bodies is associated with better discrimination. Overall, the findings suggest that the visual system has greater sensitivity to bodies in their most experienced form, which is typically upright and with a head. Otherwise, the more a face is implied by the context, as in whole figures or forward- rather than about-facing headless bodies, the better the performance as holistic/configural processing is likely stronger.

Mine, Mine, Mine: Self-Reference and Children's Retention of Novel Words.

Adults demonstrate enhanced memory for words encoded as belonging to themselves compared to those belonging to another. Known as the self-reference effect, there is evidence for the effect in children as young as three. Toddlers are efficient in linking novel words to novel objects, but have difficulties retaining multiple word-object associations. The aim here was to investigate the self-reference ownership paradigm on 3-year-old children's retention of novel words. Following exposure to each of four novel word-object pairings, children were told that objects either belonged to them or another character. Children demonstrated significantly higher immediate retention of self-referenced compared to other-referenced items. Retention was also tested 4 h later and the following morning. Retention for self- and other-referenced words was significantly higher than chance at both delayed time points, but the difference between the self- and other-referenced words was no longer significant. The findings suggest that when it comes to toddlers' retention of multiple novel words there is an initial memory enhancing effect for self- compared to other-referenced items, but the difference diminishes over time. Children's looking times during the self-reference presentations were positively associated with retention of self-referenced words 4 h later. Looking times during the other-reference presentations were positively associated with proportional looking at other-referenced items during immediate retention testing. The findings have implications for children's memory for novel words and future studies could test children's explicit memories for the ownership manipulation itself and whether the effect is superior to other forms of memory supports such as ostensive naming.

The Effect of Sleep on Children's Word Retention and Generalization.

In the first few years of life children spend a good proportion of time sleeping as well as acquiring the meanings of hundreds of words. There is now ample evidence of the effects of sleep on memory in adults and the number of studies demonstrating the effects of napping and nocturnal sleep in children is also mounting. In particular, sleep appears to benefit children's memory for recently-encountered novel words. The effect of sleep on children's generalization of novel words across multiple items, however, is less clear. Given that sleep is polyphasic in the early years, made up of multiple episodes, and children's word learning is gradual and strengthened slowly over time, it is highly plausible that sleep is a strong candidate in supporting children's memory for novel words. Importantly, it appears that when children sleep shortly after exposure to novel word-object pairs retention is better than if sleep is delayed, suggesting that napping plays a vital role in long-term word retention for young children. Word learning is a complex, challenging, and important part of development, thus the role that sleep plays in children's retention of novel words is worthy of attention. As such, ensuring children get sufficient good quality sleep and regular opportunities to nap may be critical for language acquisition.

Near or far: The effect of spatial distance and vocabulary knowledge on word learning.

The current study investigated the role of spatial distance in word learning. Two-year-old children saw three novel objects named while the objects were either in close proximity to each other or spatially separated. Children were then tested on their retention for the name-object associations. Keeping the objects spatially separated from each other during naming was associated with increased retention for children with larger vocabularies. Children with a lower vocabulary size demonstrated better retention if they saw objects in close proximity to each other during naming. This demonstrates that keeping a clear view of objects during naming improves word learning for children who have already learned many words, but keeping objects within close proximal range is better for children at earlier stages of vocabulary acquisition. The effect of distance is therefore not equal across varying vocabulary sizes. The influences of visual crowding, cognitive load, and vocabulary size on word learning are discussed.

"Are you available for the next 18 months?" - methods and aims of a longitudinal birth cohort study investigating a universal developmental surveillance program: the 'Watch Me Grow' study.

BACKGROUND: Universal developmental surveillance programs aimed at early identification and targeted early intervention significantly improve short- and long-term outcomes in children at risk of developmental disorders. However, a significant challenge remains in providing sufficiently rigorous research and robust evidence to inform policy and service delivery. This paper describes the methods of the 'Watch Me Grow' study that aims to maximise accurate early detection of children with developmental disorders through a partnership formed between policy makers, service providers and researchers. METHODS/DESIGN: A mixed methods study design was developed consisting of: (1) a qualitative study of parents and health service providers to investigate barriers and enablers of developmental surveillance; (2) recruitment of a birth cohort and their longitudinal follow-up to 18 months of age to: a) assess risk factors for not accessing existing developmental surveillance programs and b) estimate the prevalence of children identified with developmental risk; (3) comparison of surveillance outcomes with a reference standard at 18 months of age to assess the diagnostic test accuracy of existing and alternative developmental surveillance tools; and (4) comparison of developmental surveillance models to inform policy recommendations. Data linkage will be used to determine the uptake and representativeness of the study participant group versus non-participants. DISCUSSION: The Watch Me Grow study is expected to provide a collaborative opportunity to enhance universal developmental surveillance for early accurate identification of developmental risk. This will also provide quality evidence about identification of developmental risk and access to services to be embedded in existing practice with linkages to policy development.

Contextual repetition facilitates word learning via fast mapping.

The current study explores whether contextual repetition during fast mapping facilitates word learning. Three-year-old children completed fast mapping and test trials using a touchscreen computer. For half of the children, the non-targets (competitors) repeated across learning trials and for other children there was no repetition. All children received the same test trials. Children who experienced contextual repetition, that is, children for whom the competitors repeated during the initial fast mapping task, demonstrated word learning. These data demonstrate that children's word learning is facilitated by the presence of extraneous yet predictable information in the initial fast mapping task.

Sleep problems and language development in toddlers with Williams syndrome.

Sleep and related maternal beliefs were assessed in a narrow age range of 18 children with Williams syndrome (WS) and 18 typically developing (TD) children. WS is a rare genetic disorder characterised by a complex physical, cognitive and behavioural phenotype. High prevalence of sleep difficulties in older children and adults with WS have been reported. Parents completed 6 questionnaires: the Brief Infant Sleep Questionnaire, Infant Sleep Vignettes Interpretation Scale, Pittsburgh Sleep Quality Index of Parents, Child Behaviour Checklist, MacArthur Communicative Development Inventory for Infants - Words and Gestures, and the Major (ICD-10) Depression Inventory. Compared to TD children, those with WS had shorter night sleep, more night wakings and wakefulness according to parental report. Regression analyses revealed that a proportion of the variance in language development scores in WS children could be explained by night sleep duration. Compared to control parents, the mothers of the WS group were more likely to describe their child's sleep as problematic and had higher rates of involvement with child sleep, yet they had a lesser tendency to interpret sleep problems as signs of distress and a greater tendency to emphasise limit setting. Approximately half of both groups of mothers experienced poor sleep quality. This was also related to maternal mood, and night wakefulness in the children with WS. This is the first study to quantify sleep difficulties in young children with WS in a narrow age range using maternal report. The possible negative effects on maternal sleep and mood, and the link between night sleep and language development in young children with WS, requires further detailed investigation.

Socioeconomic status and functional brain development - associations in early infancy.

Socioeconomic status (SES) impacts on both structural and functional brain development in childhood, but how early its effects can be demonstrated is unknown. In this study we measured resting baseline EEG activity in the gamma frequency range in awake 6-9-month-olds from areas of East London with high socioeconomic deprivation. Between-subject comparisons of infants from low- and high-income families revealed significantly lower frontal gamma power in infants from low-income homes. Similar power differences were found when comparing infants according to maternal occupation, with lower occupational status groups yielding lower power. Infant sleep, maternal education, length of gestation, and birth weight, as well as smoke exposure and bilingualism, did not explain these differences. Our results show that the effects of socioeconomic disparities on brain activity can already be detected in early infancy, potentially pointing to very early risk for language and attention difficulties. This is the first study to reveal region-selective differences in functional brain development associated with early infancy in low-income families.

Testing a word is not a test of word learning.

Although vocabulary acquisition requires children learn names for multiple things, many investigations of word learning mechanisms teach children the name for only one of the objects presented. This is problematic because it is unclear whether children's performance reflects recall of the correct name-object association or simply selection of the only object that was singled out by being the only object named. Children introduced to one novel name may perform at ceiling as they are not required to discriminate on the basis of the name per se, and appear to rapidly learn words following minimal exposure to a single word. We introduced children to four novel objects. For half the children, only one of the objects was named and for the other children, all four objects were named. Only children introduced to one word reliably selected the target object at test. This demonstration highlights the over-simplicity of one-word learning paradigms and the need for a shift in word learning paradigms where more than one word is taught to ensure children disambiguate objects on the basis of their names rather than their degree of salience.

Brain responses to audiovisual speech mismatch in infants are associated with individual differences in looking behaviour.

Research on audiovisual speech integration has reported high levels of individual variability, especially among young infants. In the present study we tested the hypothesis that this variability results from individual differences in the maturation of audiovisual speech processing during infancy. A developmental shift in selective attention to audiovisual speech has been demonstrated between 6 and 9 months with an increase in the time spent looking to articulating mouths as compared to eyes (Lewkowicz & Hansen-Tift. (2012) Proc. Natl Acad. Sci. USA, 109, 1431-1436; Tomalski et al. (2012) Eur. J. Dev. Psychol., 1-14). In the present study we tested whether these changes in behavioural maturational level are associated with differences in brain responses to audiovisual speech across this age range. We measured high-density event-related potentials (ERPs) in response to videos of audiovisually matching and mismatched syllables /ba/ and /ga/, and subsequently examined visual scanning of the same stimuli with eye-tracking. There were no clear age-specific changes in ERPs, but the amplitude of audiovisual mismatch response (AVMMR) to the combination of visual /ba/ and auditory /ga/ was strongly negatively associated with looking time to the mouth in the same condition. These results have significant implications for our understanding of individual differences in neural signatures of audiovisual speech processing in infants, suggesting that they are not strictly related to chronological age but instead associated with the maturation of looking behaviour, and develop at individual rates in the second half of the first year of life.

The right thing at the right time: why ostensive naming facilitates word learning.

The current study examines how focusing children's attention immediately after fast mapping improves their ability to retain novel names. Previous research suggests that young children can only retain novel names presented via referent selection if ostensive naming is provided and that such explicit naming works by increasing children's attention to the target and decreasing their attention to the competitor objects (Horst and Samuelson, 2008). This explanation of the function of ostensive naming after referent selection trials was tested by drawing 24-month-old children's attention to the target either by illuminating the target, covering the competitors, or both. A control group was given a social pragmatic cue (pointing). Children given social pragmatic cue support did not demonstrate retention. However, children demonstrated retention if the target object was illuminated, and also when it was illuminated and the competitors simultaneously dampened. This suggests that drawing children's attention to the target object in a manner that helps focus children's attention is critical for word learning via referent selection. Directing attention away from competitors while also directing attention toward a target also aids in the retention of novel words.

During pregnancy, recreational drug-using women stop taking ecstasy (3,4-methylenedioxy-N-methylamphetamine) and reduce alcohol consumption, but continue to smoke tobacco and cannabis: initial findings from the Development and Infancy Study.

While recreational drug use in UK women is prevalent, to date there is little prospective data on patterns of drug use in recreational drug-using women immediately before and during pregnancy. A total of 121 participants from a wide range of backgrounds were recruited to take part in the longitudinal Development and Infancy Study (DAISY) study of prenatal drug use and outcomes. Eighty-six of the women were interviewed prospectively while pregnant and/or soon after their infant was born. Participants reported on use immediately before and during pregnancy and on use over their lifetime. Levels of lifetime drug use of the women recruited were high, with women reporting having used at least four different illegal drugs over their lifetime. Most users of cocaine, 3,4-methylenedioxy-N-methylamphetamine (MDMA) and other stimulants stopped using these by the second trimester and levels of use were low. However, in pregnancy, 64% of the sample continued to use alcohol, 46% tobacco and 48% cannabis. While the level of alcohol use reduced substantially, average tobacco and cannabis levels tended to be sustained at pre-pregnancy levels even into the third trimester (50 cigarettes and/or 11 joints per week). In sum, while the use of 'party drugs' and alcohol seems to reduce, levels of tobacco and cannabis use are likely to be sustained throughout pregnancy. The data provide polydrug profiles that can form the basis for the development of more realistic animal models.

Infants perceive human point-light displays as solid forms.

While five-month-old infants show orientation-specific sensitivity to changes in the motion and occlusion patterns of human point-light displays, it is not known whether infants are capable of binding a human representation to these displays. Furthermore, it has been suggested that infants do not encode the same physical properties for humans and material objects. To explore these issues we tested whether infants would selectively apply the principle of solidity to upright human displays. In the first experiment infants aged six and nine months were repeatedly shown a human point-light display walking across a computer screen up to 10 times or until habituated. Next, they were repeatedly shown the walking display passing behind an in-depth representation of a table, and finally they were shown the human display appearing to pass through the table top in violation of the solidity of the hidden human form. Both six- and nine-month-old infants showed significantly greater recovery of attention to this final phase. This suggests that infants are able to bind a solid vertical form to human motion. In two further control experiments we presented displays that contained similar patterns of motion but were not perceived by adults as human. Six- and nine-month-old infants did not show recovery of attention when a scrambled display or an inverted human display passed through the table. Thus, the binding of a solid human form to a display in only seems to occur for upright human motion. The paper considers the implications of these findings in relation to theories of infants' developing conceptions of objects, humans and animals.

Infants perceive human point-light displays as solid forms.

While five-month-old infants show orientation-specific sensitivity to changes in the motion and occlusion patterns of human point-light displays, it is not known whether infants are capable of binding a human representation to these displays. Furthermore, it has been suggested that infants do not encode the same physical properties for humans and material objects. To explore these issues we tested whether infants would selectively apply the principle of solidity to upright human displays. In the first experiment infants aged six and nine months were repeatedly shown a human point-light display walking across a computer screen up to 10 times or until habituated. Next, they were repeatedly shown the walking display passing behind an in-depth representation of a table, and finally they were shown the human display appearing to pass through the table top in violation of the solidity of the hidden human form. Both six- and nine-month-old infants showed significantly greater recovery of attention to this final phase. This suggests that infants are able to bind a solid vertical form to human motion. In two further control experiments we presented displays that contained similar patterns of motion but were not perceived by adults as human. Six- and nine-month-old infants did not show recovery of attention when a scrambled display or an inverted human display passed through the table. Thus, the binding of a solid human form to a display in only seems to occur for upright human motion. The paper considers the implications of these findings in relation to theories of infants' developing conceptions of objects, humans and animals.