What's the point? Infants' and adults' perception of different pointing gestures.

Adults and infants as young as 4 months old orient to pointing gestures. Although adults are shown to orient faster to index-finger pointing than other hand shapes, it is unknown whether hand shapes influence infants' perception of pointing. In this study, we used a spatial cueing paradigm on an eye tracker to investigate whether and to what extent adults and 12-month-old infants orient their attention in the direction of pointing gestures with different hand shapes: index finger, whole hand, and pinky finger. Furthermore, we assessed infants' and their parents' pointing production. Results revealed that adults showed a reliable cueing effect: shorter saccadic reaction times (SRTs) to congruent than incongruent targets, for all hand shapes. However, they did not show a larger cueing effect triggered by the index or any other finger. This contradicts previous findings and is discussed with respect to the differences in methodology. Infants showed a cueing effect only for the whole hand but not for the index or pinky fingers. The current results suggest that infants' orienting to pointing may be more robust for the whole hand shape in the first year, and tuning in to the social-communicative relevance of the canonical index finger shape may develop later or require additional social-communicative cues.

Automatic imitation in school-aged children.

Children imitate others for different reasons: To learn from others and to reach social goals such as affiliation or prosociality. So far, imitative acts have been measured using diverging methods in children and adults. Here, we investigated whether school-aged children's imitation can be measured via their automatic imitation with a classical imitation-inhibition task (Brass et al., 2000) as has been used in adults. To this end, we measured automatic imitation in N=94 7-8-year-olds and N=10 adults. The results were similar in children and adults: Observing actions that are incongruent with participants' actions interferes with their responses resulting in increased reaction times and error rates. This shows that assessing automatic imitation via the imitation-inhibition task is feasible in children, and creates the basis for future studies to compare the behaviour of different age groups with the same imitation task.

Childhood poisonings: Effects of ambiguous product characteristics on preschool children's categorization of household chemicals.

This study investigated preschool children's categorization and risk perception of products with ambiguous product characteristics (e.g., food-like packaging). These characteristics make it difficult for preschool children to categorize household chemicals correctly. This, therefore, increases the risk of unintentional poisoning. We hypothesized that ambiguity arises from different product characteristics, such as the type of packaging, the products' scent, or the packaging's color and transparency. In four behavioral tasks, N = 108 preschool children (M = 43 months, SD = 3) categorized different products and household chemicals with various types of packaging, colors, and scents. Individually wrapped dishwasher tablets were more likely to be categorized as edible than unwrapped ones. Furthermore, children who had interacted with any type of dishwasher tablet in the last 6 months performed better in identifying dishwasher tablets, regardless of packaging type. Household chemicals with a fruity scent were more likely to be categorized as drinkable than those with a chlorine scent. Finally, the children considered black bottles more dangerous and preferred them less than bottles of a different color. In contrast, bottle transparency generally did not seem to affect risk perception and preference. These findings confirm that ambiguous product characteristics influence children's categorization of unknown products and, thus, their risk perception and decision-making. Manufacturers and caregivers are advised to reduce the ambiguity of household chemicals by designing more neutral product packaging and choosing products with more neutral elements, respectively.

Atypical gaze-following behaviour in infants with congenital heart disease.

BACKGROUND: Neurodevelopmental impairments are the most prevalent non-cardiac long-term sequelae in children with complex congenital heart disease (CHD). Deficits include the social-emotional and social-cognitive domains. Little is known about the predecessors of social-cognitive development in infants with CHD during the first year of life. Gaze-following behaviour can be used to measure early social-cognitive abilities. AIMS: To assess gaze-following development in infants with CHD compared to healthy controls. STUDY DESIGN: Prospective cohort study. PARTICIPANTS: Twenty-three infants who underwent neonatal correction for CHD and 84 healthy controls. OUTCOME MEASURES: Gaze-following behaviour was assessed by eye tracking at 6 and 12 months. Difference scores for first fixation, fixation frequency and fixation duration towards the gaze-cued object were calculated across 6 trials and compared between groups at both testing time points while adjusting for known confounders. Linear mixed models were calculated to assess the longitudinal trajectory of gaze-following development while accounting for the nested and dependent data structure. RESULTS: At 6 months, no difference in gaze-following behaviour between CHD and healthy controls was found. At 12 months, fixation frequency towards the gaze-cued was lower and looking duration was shorter in CHD compared to controls (p = 0.0077; p = 0.0068). Infants with CHD showed less increase with age in the fixation frequency towards the congruent object (p = 0.041) compared to controls. CONCLUSION: During the first year of life, gaze-following development diverges in infants with CHD compared to healthy controls. Further research is needed to investigate the clinical relevance of these findings and the association with later social-cognitive development.

Seeing household chemicals through the eyes of children-Investigating influential factors of preschoolers' perception and behavior.

INTRODUCTION: Children who encounter household chemicals run the risk of unintentional injury. The aim of this study was to understand which factors heighten children's attention or misguide their decision-making concerning household chemicals. We hypothesized that certain product attributes (i.e., label, packaging, closure types), storage context, and parental beliefs play a role in this setting. METHOD: We conducted a laboratory study with N = 114 children (M = 45 months, SD = 6.5) and their parents (M = 38 years, SD = 4.92). Children completed a series of behavioral tasks in which they had to choose between products with different attributes, identify products in different storage contexts, and sort household chemicals. RESULTS: The results confirmed that the children preferred products with cartoon-style labels compared to products without such labels. However, children's decision-making did not differ for products with different closure types (child-resistant vs sprayer-type closures). Regarding the storage context, our results showed that the children particularly struggled to identify dishwashing tabs when they were stored with other food items rather than household chemicals. In terms of parental beliefs, our study found that parents rated more household chemicals as child-safe than their children did. PRACTICAL APPLICATION: Parents should buy household chemicals with neutral labels and pay attention to how their household chemicals are stored. Manufacturers should consider potential adverse effects when developing new product designs.

Exploring the role of COVID-19 pandemic-related changes in social interactions on preschoolers' emotion labeling.

During the COVID-19 pandemic people were increasingly obliged to wear facial masks and to reduce the number of people they met in person. In this study, we asked how these changes in social interactions are associated with young children's emotional development, specifically their emotion recognition via the labeling of emotions. Preschoolers labeled emotional facial expressions of adults (Adult Faces Task) and children (Child Faces Task) in fully visible faces. In addition, we assessed children's COVID-19-related experiences (i.e., time spent with people wearing masks, number of contacts without masks) and recorded children's gaze behavior during emotion labeling. We compared different samples of preschoolers (4.00-5.75 years): The data for the no-COVID-19-experience sample were taken from studies conducted before the pandemic (Adult Faces Task: N = 40; Child Faces Task: N = 30). The data for the with-COVID-19-experience sample (N = 99) were collected during the COVID-19 pandemic in Switzerland between June and November 2021. The results did not indicate differences in children's labeling behavior between the two samples except for fearful adult faces. Children with COVID-19-experience more often labeled fearful faces correctly compared to children with no COVID-19 experience. Furthermore, we found no relations between children's labeling behavior, their individual COVID-19-related experiences, and their gaze behavior. These results suggest that, even though the children had experienced differences in the amount and variability of facial input due to the pandemic, they still received enough input from visible faces to be able to recognize and label different emotions.

How experience shapes infants' communicative behaviour: Comparing gaze following in infants with and without pandemic experience.

The COVID-19 pandemic has been influencing people's social life substantially. Everybody, including infants and children needed to adapt to changes in social interactions (e.g., social distancing) and to seeing other people wearing facial masks. In this study, we investigated whether these pandemic-related changes influenced 12- to 15-months-old infants' reactions to observed gaze shifts (i.e., their gaze following). In two eye-tracking tasks, we measured infants' gaze-following behavior during the pandemic (with-COVID-19-experience sample) and compared it to data of infants tested before the pandemic (no-COVID-19-experience sample). Overall, the results indicated no significant differences between the two samples. However, in one sub-task infants in the with-COVID-19-experience sample looked longer at the eyes of a model compared to the no-COVID-19-experience sample. Within the with-COVID-19-experience sample, the amount of mask exposure and the number of contacts without mask were not related to infants' gaze-following behavior. We speculate that even though infants encounter fewer different people during the pandemic and are increasingly exposed to people wearing facial masks, they still also see non-covered faces. These contacts might be sufficient to provide infants with the social input they need to develop social and emotional competencies such as gaze following.

The kleineWeltentdecker App - A smartphone-based developmental diary.

Today, a vast number of tools exist to measure development in early childhood in a variety of domains such as cognition, language, or motor, cognition. These tools vary in different aspects. Either children are examined by a trained experimenter, or caregivers fill out questionnaires. The tools are applied in the controlled setting of a laboratory or in the children's natural environment. While these tools provide a detailed picture of the current state of children's development, they are at the same time subject to several constraints. Furthermore, the measurement of an individual child's change of different skills over time requires not only one measurement but high-density longitudinal assessments. These assessments are time-consuming, and the breadth of developmental domains assessed remains limited. In this paper, we present a novel tool to assess the development of skills in different domains, a smartphone-based developmental diary app (the kleineWeltentdecker App, henceforth referred to as the APP (The German expression "kleine Weltentdecker" can be translated as "young world explorers".)). By using the APP, caregivers can track changes in their children's skills during development. Here, we report the construction and validation of the questionnaires embedded in the APP as well as the technical details. Empirical validations with children of different age groups confirmed the robustness of the different measures implemented in the APP. In addition, we report preliminary findings, for example, on children's communicative development by using existing APP data. This substantiates the validity of the assessment. With the APP, we put a portable tool for the longitudinal documentation of individual children's development in every caregiver's pocket, worldwide.

A multi-lab study of bilingual infants: Exploring the preference for infant-directed speech.

From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants' IDS preference. As part of the multi-lab ManyBabies 1 project, we compared lab-matched samples of 333 bilingual and 385 monolingual infants' preference for North-American English IDS (cf. ManyBabies Consortium, 2020: ManyBabies 1), tested in 17 labs in 7 countries. Those infants were tested in two age groups: 6-9 months (the younger sample) and 12-15 months (the older sample). We found that bilingual and monolingual infants both preferred IDS to ADS, and did not differ in terms of the overall magnitude of this preference. However, amongst bilingual infants who were acquiring North-American English (NAE) as a native language, greater exposure to NAE was associated with a stronger IDS preference, extending the previous finding from ManyBabies 1 that monolinguals learning NAE as a native language showed a stronger preference than infants unexposed to NAE. Together, our findings indicate that IDS preference likely makes a similar contribution to monolingual and bilingual development, and that infants are exquisitely sensitive to the nature and frequency of different types of language input in their early environments.

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.

Do you understand what I want to tell you? Early sensitivity in bilinguals' iconic gesture perception and production.

Previous research has shown differences in monolingual and bilingual communication. We explored whether monolingual and bilingual pre-schoolers (N = 80) differ in their ability to understand others' iconic gestures (gesture perception) and produce intelligible iconic gestures themselves (gesture production) and how these two abilities are related to differences in parental iconic gesture frequency. In a gesture perception task, the experimenter replaced the last word of every sentence with an iconic gesture. The child was then asked to choose one of four pictures that matched the gesture as well as the sentence. In a gesture production task, children were asked to indicate 'with their hands' to a deaf puppet which objects to select. Finally, parental gesture frequency was measured while parents answered three different questions. In the iconic gesture perception task, monolingual and bilingual children did not differ. In contrast, bilinguals produced more intelligible gestures than their monolingual peers. Finally, bilingual children's parents gestured more while they spoke than monolingual children's parents. We suggest that bilinguals' heightened sensitivity to their interaction partner supports their ability to produce intelligible gestures and results in a bilingual advantage in iconic gesture production.

Higher levels of motor competence are associated with reduced interference in action perception across the lifespan.

Action perception and action production are tightly linked and elicit bi-directional influences on each other when performed simultaneously. In this study, we investigated whether age-related differences in manual fine-motor competence and/or age affect the (interfering) influence of action production on simultaneous action perception. In a cross-sectional eye-tracking study, participants of a broad age range (N = 181, 20-80 years) observed a manual grasp-and-transport action while performing an additional motor or cognitive distractor task. Action perception was measured via participants' frequency of anticipatory gaze shifts towards the action goal. Manual fine-motor competence was assessed with the Motor Performance Series. The interference effect in action perception was greater in the motor than the cognitive distractor task. Furthermore, manual fine-motor competence and age in years were both associated with this interference. The better the participants' manual fine-motor competence and the younger they were, the smaller the interference effect. However, when both influencing factors (age and fine-motor competence) were taken into account, a model including only age-related differences in manual fine-motor competence best fit with our data. These results add to the existing literature that motor competence and its age-related differences influence the interference effects between action perception and production.

The dynamics of the interrelation of perception and action across the life span.

Successful social interaction relies on the interaction partners' perception, anticipation and understanding of their respective actions. The perception of a particular action and the capability to produce this action share a common representational ground. So far, no study has explored the interrelation between action perception and production across the life span using the same tasks and the same measurement techniques. This study was designed to fill this gap. Participants between 3 and 80 years (N = 214) observed two multistep actions of different familiarities and then reproduced the according actions. Using eye tracking, we measured participants' action perception via their prediction of action goals during observation. To capture subtler perceptual processes, we additionally analysed the dynamics and recurrent patterns within participants' gaze behaviour. Action production was assessed via the accuracy of the participants' reproduction of the observed actions. No age-related differences were found for the perception of the familiar action, where participants of all ages could rely on previous experience. In the unfamiliar action, where participants had less experience, action goals were predicted more frequently with increasing age. The recurrence in participants' gaze behaviour was related to both, age and action production: gaze behaviour was more recurrent (i.e. less flexible) in very young and very old participants, and lower levels of recurrence (i.e. greater flexibility) were related to higher scores in action production across participants. Incorporating a life-span perspective, this study illustrates the dynamic nature of developmental differences in the associations of action production with action perception.

Bilingual Children Adapt to the Needs of Their Communication Partners, Monolinguals Do Not.

We explored the ability of children to adapt their communication to the needs of their communication partner. Monolingual and bilingual 3-year-old children (N = 110) observed two puppets looking for puzzle pieces. One puppet showed its appreciation of the children's help, the other puppet wanted to solve the puzzle on its own. The children's communicative acts were coded in terms of level of ostension (how obviously they indicated the hiding place of the puzzle piece) and level of information (how clearly they indicated the location). Monolinguals and bilinguals were equally helpful and informative. In contrast, only bilingual children adapted their level of ostension selectively between the two puppets. These findings point to the greater skills of bilinguals to adapt their communication accordingly.

Interference of action perception on action production increases across the adult life span.

Action perception and action production are assumed to be based on an internal simulation process that involves the sensorimotor system. This system undergoes changes across the life span and is assumed to become less precise with age. In the current study, we investigated how increasing age affects the magnitude of interference in action production during simultaneous action perception. In a task adapted from Brass et al. (Brain Cogn 44(2):124-143, 2000), we asked participants (aged 20-80 years) to respond to a visually presented finger movement and/or symbolic cue by executing a previously defined finger movement. Action production was assessed via participants' reaction times. Results show that participants were slower in trials in which they were asked to ignore an incongruent finger movement compared to trials in which they had to ignore an incongruent symbolic cue. Moreover, advancing age was shown to accentuate this effect. We suggest that the internal simulation of the action becomes less precise with age making the sensorimotor system more susceptible to perturbations such as the interference of a concurrent action perception.

Bilingual toddlers have advanced abilities to repair communication failure.

Recent research has demonstrated enhanced communicative abilities in bilingual children compared with monolingual children throughout childhood and in a variety of domains. The processes underlying these advantages are, however, not well understood. It has been suggested that one aspect that particularly stimulates bilinguals' communication skills is their daily experience with challenging communication. In the current study, we investigated whether children's assumed experience with communication failures would increase their skills when it came to repairing communication failure. Non-German bilingual, German bilingual, and monolingual 2.5-year-old toddlers participated in a communication task in which a misunderstanding occurred. We hypothesized that monolingual and German bilingual children would have fewer daily communication failures-and, therefore, less well-trained repair skills-compared with non-German bilinguals. The results showed that non-German bilinguals were more likely to repair the misunderstanding compared with both monolingual children and German bilingual children. The current findings support the view that the communicative advantages of bilingual individuals develop based on their unique experience with interpersonal communication and its difficulties.