Speaker Competence Affects Prefrontal Theta and Occipital Alpha Power during Selective Word Learning in Preschoolers.

In the present study, we investigated the cognitive processes underlying selective word learning in preschoolers. We measured rhythmic neural activity in the theta (4-8 Hz) and alpha frequency range (7-12 Hz) in 67 four-year-olds. EEG was recorded during anticipation and encoding of novel labeling events performed by a speaker who had previously shown either competence (correct) or incompetence (incorrect) in labeling familiar objects. In both groups, children selected the target object equally often upon recall. However, children observing the incompetent speaker revealed weaker representations of novel words indicated by an increased likelihood for selecting familiar but incorrect items upon recall. Modulations in theta and alpha power suggest differential processing of novel label-object pairs depending on the speakers' competence. In the incompetent, but not the competent, speaker condition, increases in prefrontal theta power during anticipation and encoding were related to increased recall success. Findings suggest that theta power in the present study reflects cognitive control. In both conditions, occipital alpha power-indicating attentional processes-reflected familiarity with novel items, but in opposite directions. In familiar item trials, alpha power was increased observing the incompetent and decreased observing the competent speaker. Thus, both cognitive control and attention processes during word learning are differentially affected by speaker characteristics.

The proximate regulation of prosocial behaviour: towards a conceptual framework for comparative research.

Humans and many other animal species act in ways that benefit others. Such prosocial behaviour has been studied extensively across a range of disciplines over the last decades, but findings to date have led to conflicting conclusions about prosociality across and even within species. Here, we present a conceptual framework to study the proximate regulation of prosocial behaviour in humans, non-human primates and potentially other animals. We build on psychological definitions of prosociality and spell out three key features that need to be in place for behaviour to count as prosocial: benefitting others, intentionality, and voluntariness. We then apply this framework to review observational and experimental studies on sharing behaviour and targeted helping in human children and non-human primates. We show that behaviours that are usually subsumed under the same terminology (e.g. helping) can differ substantially across and within species and that some of them do not fulfil our criteria for prosociality. Our framework allows for precise mapping of prosocial behaviours when retrospectively evaluating studies and offers guidelines for future comparative work.

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.

Dynamic interaction patterns of monolingual and bilingual infants with their parents.

Bilingual children show a number of advantages in the domain of communication. The aim of the current study was to investigate whether differences in interactions are present before productive language skills emerge. For a duration of 5 minutes, 64 parents and their 14-month-old infants explored a decorated room together. The coordination of their behaviors in the modalities of action, language, and gesture was coded. The results showed no differences in interactions across different language statuses. In two additional analyses, we first compared monolinguals and bilinguals with caregivers who shared the same language and culture. Results showed the same pattern of non-difference. Second, we compared bilinguals with caregivers from different cultures. The rate and duration of coordination differed across infants with different cultural backgrounds. The findings suggest that exposure to two languages is not sufficient to explain the previously identified beneficial effects in the communicative interactions of bilingual children.

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.

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.

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.

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.

How preschoolers react to norm violations is associated with culture.

Children from the age of 3years understand social norms as such and enforce these norms in interactions with others. Differences in parental and institutional education across cultures make it likely that children receive divergent information about how to act in cases of norm violations. In the current study, we investigated whether cultural values are associated with the ways in which children react to norm violations. We tested 80 bicultural 3-year-olds with a norm enforcement paradigm and analyzed their reactions to norm violations. The reactions were correlated to the children's parental cultural values using the Global Leadership and Organizational Behavior Effectiveness (GLOBE) scales, and these results show that parental culture was associated with children's reactions to norm violations. The three strongest correlations were found for institutional collectivism, performance orientation, and assertiveness.

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.

Effects of movement distance, duration, velocity, and type on action prediction in 12-month-olds.

The goal of the present study was to test the influence of the spatial and temporal dynamics of observed manual actions on infants' action prediction. Twelve-month-old infants were presented with reach-and-transport actions performed by a human agent. Movement distance, duration, and - resulting from the two - movement velocity were systematically varied. Action prediction was measured via the latency of gaze arrival at target in relation to agent's hand. The results showed a general effect of all parameters on the infants' perception of goal-directed actions: Infants were more likely to predict the action goal the longer the movement distance was, the longer the movement duration was, and the slower the movement velocity was. In addition, they were more likely to predict the goal of a reaching than a transport action. The present findings extent previous findings by showing that infants are not only sensitive to differences in distances, durations, and velocities at early age but that these factors have a strong impact on the prediction of the goal of observed actions.

Measuring action understanding: Relations between goal prediction and imitation.

We explored the developmental course of goal prediction and imitation as two commonly used measures of action understanding. In particular, we investigated the relationships between the measures in two complex multistep actions (hammering and pulling action) in children between 12 and 30 months (n = 64) in a between-subjects design. The results showed that the prediction of an action goal was related to the imitation in the hammering action, but not in the pulling action. The results are discussed in the light of current theories on goal prediction and imitation.

Intra-individual variability and continuity of action and perception measures in infants.

The development of action and perception, and their relation in infancy is a central research area in socio-cognitive sciences. In this Perspective Article, we focus on the developmental variability and continuity of action and perception. At group level, these skills have been shown to consistently improve with age. We would like to raise awareness for the issue that, at individual level, development might be subject to more variable changes. We present data from a longitudinal study on the perception and production of contralateral reaching skills of infants aged 7, 8, 9, and 12 months. Our findings suggest that individual development does not increase linearly for action or for perception, but instead changes dynamically. These non-continuous changes substantially affect the relation between action and perception at each measuring point and the respective direction of causality. This suggests that research on the development of action and perception and their interrelations needs to take into account individual variability and continuity more progressively.

Limitations to the cultural ratchet effect in young children.

Although many animal species show at least some evidence of cultural transmission, broadly defined, only humans show clear evidence of cumulative culture. In the current study, we investigated whether young children show the "ratchet effect," an important component of cumulative culture--the ability to accumulate efficient modifications across generations. We tested 16 diffusion chains--altogether consisting of 80 children--to see how they solved an instrumental task (i.e., carrying something from one location to another). We found that when the chain was seeded with an inefficient way of solving the task, 4-year-olds were able to innovate and transmit these innovations so as to reach a more efficient solution. However, when it started out with relatively efficient solutions already (i.e., the ones that children in a control condition discovered for themselves), there were no further techniques invented and/or transmitted beyond that. Thus, young children showed the ratchet effect to a limited extent, accumulating efficient modifications but not going beyond the inventive level of the individual.