Large-scale data decipher children's scale errors: A meta-analytic approach using the zero-inflated Poisson models.

Scale errors are intriguing phenomena in which a child tries to perform an object-specific action on a tiny object. Several viewpoints explaining the developmental mechanisms underlying scale errors exist; however, there is no unified account of how different factors interact and affect scale errors, and the statistical approaches used in the previous research do not adequately capture the structure of the data. By conducting a secondary analysis of aggregated datasets across nine different studies (n = 528) and using more appropriate statistical methods, this study provides a more accurate description of the development of scale errors. We implemented the zero-inflated Poisson (ZIP) regression that could directly handle the count data with a stack of zero observations and regarded developmental indices as continuous variables. The results suggested that the developmental trend of scale errors was well documented by an inverted U-shaped curve rather than a simple linear function, although nonlinearity captured different aspects of the scale errors between the laboratory and classroom data. We also found that repeated experiences with scale error tasks reduced the number of scale errors, whereas girls made more scale errors than boys. Furthermore, a model comparison approach revealed that predicate vocabulary size (e.g., adjectives or verbs), predicted developmental changes in scale errors better than noun vocabulary size, particularly in terms of the presence or absence of scale errors. The application of the ZIP model enables researchers to discern how different factors affect scale error production, thereby providing new insights into demystifying the mechanisms underlying these phenomena. A video abstract of this article can be viewed at https://youtu.be/1v1U6CjDZ1Q RESEARCH HIGHLIGHTS: We fit a large dataset by aggregating the existing scale error data to the zero-inflated Poisson (ZIP) model. Scale errors peaked along the different developmental indices, but the underlying statistical structure differed between the in-lab and classroom datasets. Repeated experiences with scale error tasks and the children's gender affected the number of scale errors produced per session. Predicate vocabulary size (e.g., adjectives or verbs) better predicts developmental changes in scale errors than noun vocabulary size.

Young children's subjective and objective thresholds and emergent processes of visual consciousness using a backward masking task.

Visual consciousness studies in humans have primarily focused on adults. However, whether young children's visual consciousness is similar to or different from that of adults remains unknown. This study examined young children's and adults' subjective awareness and objective discrimination for thresholds and emergent processes of visual consciousness in two experiments. In Experiment 1, 20 5-6-year-olds and 20 adults attempted a figure discrimination task using a square or a diamond as the target stimulus and responded, using a two-point scale, to a question on subjective awareness of the target stimulus with stimulus onset asynchronies (SOA) from 20 to 260 ms. In Experiment 2, 31 5-6-year-olds and 16 adults attempted the task and responded, using a four-point scale, to a question on subjective awareness with SOA from 50 to 550 ms. We measured the discrimination accuracy and the awareness scale with SOA and fit them to the sigmoid function. The results showed that the objective accuracy threshold of young children was larger than that of adults. Moreover, young children's subjective awareness threshold was larger than that of adults in the four-point but not in the two-point scale responses. Finally, there were no age differences in the emergent process of consciousness. This study suggests that the emergent process of consciousness in young children is similar to that in adults, however, the threshold in young children is larger than that in adults.

The contextual cueing effect disappears during joint search in preschool children.

During preschool years, children's interacting with others increases. One of the involved developmental skills is task co-representation, through which children aged 5 years and older represent a partner's task in a similar way to their own task. In adults, task co-representation makes participants attend to and form memories of objects relevant to both their own task and their partner's task; however, it is unclear whether children can also form such memories. In Experiment 1, we examined the memory facilitation of joint search using a contextual cueing effect paradigm. Children were presented with search displays repeatedly with the same or random layouts and searched and responded to the target either alone (the single group; n = 32; Mage = 73.6 months, range = 61-80) or with their parent (the joint group; n = 32; Mage = 74.3 months, range = 64-81). Results showed that the search with the same layouts was faster than that with the random layouts for the single group, indicating that children form associative memories of target and distractors relevant to their own task. For the joint group, this effect was not statistically different from that of the single group, with exploratory analysis suggesting that it was disrupted. In Experiment 2, children performed the search with a peer (n = 32; Mage = 72.7 months, range = 67-79) and the effect was also not found. Our findings suggest that the self's and partner's tasks are represented but might not be incorporated into associative memory in 5- and 6-year-old children.

Visual memory of a co-actor's target during joint search.

Studies on joint action show that when two actors turn-takingly attend to each other's target that appears one at a time, a partner's target is accumulated in memory. However, in the real world, actors may not be certain that they attend to the same object because multiple objects often appear simultaneously. In this study, we asked participant pairs to search for different targets in parallel from multiple objects and investigated the memory of a partner's target. We employed the contextual cueing paradigm, in which repetitive search forms associative memory between a target and a configuration of distractors that facilitates search. During the learning phase, exemplars of three target categories (i.e., bird, shoe, and tricycle) were presented among unique objects, and participant pairs searched for them. In Experiment 1, it was followed by a memory test about target exemplars. Consequently, the partner's target was better recognized than the target that nobody searched for. In Experiments 2a and 2b, the memory test was replaced with the transfer phase, where one individual from the pair searched for the category that nobody had searched for while the other individual searched for the category the partner had searched for in the learning phase. The transfer phase did not show search facilitation underpinned by associative memory between the partner's target and distractors. These results suggest that when participant pairs search for different targets in parallel, they accumulate the partner's target in memory but may not form its associative memory with the distractors that facilitates its search.

The Relationship Between Hostile Intent Attribution and Aggression in Japanese Children.

Previous studies showed that hostile intent attribution (HIA) was significantly correlated with and contributed to the development of aggression in children. Studies that directly examined the factors that explained the relationship between HIA and aggression are lacking. Hence, this study investigated (a) the correlation between HIA and aggression and (b) the variables (hyperactivity, prosociality, and collaborative problem-solving) that mediated the relationship between HIA and aggression in Japanese children aged 4-9 years. The participants were 180 children and their caregivers. First, the caregivers reported their children's aggression, hyperactivity, prosociality, and collaborative problem-solving through questionnaires. Next, the children worked on an HIA task. The results showed a weak positive correlation between HIA and aggression. Furthermore, significant indirect effects were observed among all the mediation models. The model that contained all three mediators yielded the smallest Akaike Information Criterion value. In this model, the indirect effect was significant only for the path with hyperactivity as the mediator. These findings provide several suggestions for revealing the mechanism of the relationship between HIA and aggression during childhood. Notably, children's hyperactivity was suggested to play a particularly important role in the relationship between HIA and aggression.

Relationship between cool and hot executive function in young children: A near-infrared spectroscopy study.

A theoretical distinction exists between the cool and hot aspects of executive function (EF). At the neural level, cool EF may be associated with activation in the lateral prefrontal cortex and the anterior cingulate cortex, whereas the orbitofrontal cortex may play a key role in hot EF. However, some recent studies have shown that young children show activity in the lateral prefrontal regions during hot EF tasks, suggesting that the distinction between hot and cool EF may not be as marked. Nevertheless, few neuroimaging studies have directly examined the relationship between cool and hot EF. In this study, preschool children (N = 46, mean age = 66.1 months) were given both cool (Dimensional Change Card Sort (DCCS) and Stroop-like tasks) and hot (delay of gratification) EF tasks, and neural activation during these tasks was measured using functional near-infrared spectroscopy (fNIRS). Correlational analyses and analysis of variance (ANOVA) were conducted to assess the relationship between cool and hot EF. At the behavioral level, a moderate correlation was found between DCCS and Stroop-like tasks, but no correlation emerged between cool and hot EF tasks. At the neural level, prefrontal activations during the cool EF tasks did not correlate with those during the hot EF task. Further, children showed stronger prefrontal activations during the DCCS tasks compared to the delay of gratification tasks. The results suggest that the neural basis of hot and cool EF may differ during early childhood.

Object labeling activates young children's scale errors at an early stage of verb vocabulary growth.

Scale errors are intriguing developmental phenomena in which young children attempt to perform impossible object-specific actions toward miniature-sized objects. Of several related cognitive abilities, lexical development during toddlerhood enhances scale error production by making objects' semantic representations dominant over perceptual information. To directly address the effect of activated semantic representations on scale errors, we examined whether and when object labeling affected scale errors. Toddlers aged 18 to 30 months (N = 72) performed a body-based scale error task twice: in one session with specific object labels provided (e.g., "chair") and in the other session with general pronouns provided (e.g., "this"). Using different developmental indices, including chronological age and productive vocabulary size of nouns, verbs, and adjectives, the enhancement effect of object labeling was detected only for children whose verb vocabulary size was classified into the medium group (3-26 words). Moreover, verb vocabulary size was determined to be the best predictor of scale error production among the candidate developmental indices. We also found that toddlers produced more scale errors in the first session that they performed the task compared with the second session. In addition to revealing that careful control of relevant factors (e.g., developmental indices, labeling, task repetition) is required for scale error research, this study sheds light on the relevance of verb vocabulary on scale errors.

Visual image of God/gods during early childhood.

This study examined whether Japanese children have a different visual image of God/gods than children from Western countries, who have an image of an old White man. Study 1 comprised 183, 4-7-year-old Japanese children (93 girls), who had to choose a face that looked like God/gods from among pictures of faces that differed on age (e.g., young Asian man vs. old Asian man), race (e.g., White woman vs. Black woman vs. Asian woman), or gender (e.g., Asian man vs. Asian woman). Children's responses were relatively biased toward old or White faces, but only boys were weakly biased toward male faces. Study 2 confirmed that children did not have a strong gender bias. Japanese children conceptualise God/gods as old or White.

Are there sex differences in the development of prefrontal function during early childhood?

Research has demonstrated the possibility of minor sex differences in executive function (EF) development of young children; however, this may be limited to the measurements used in previous studies (questionnaires and cognitive tasks), which tend to be less sensitive to the detection of sex differences. The present study uses brain measures to examine the effect of sex on EF development. In this study, preschool children were given an EF task, and patterns of activation in the lateral prefrontal regions were measured by a functional near-infrared spectroscopy. In Study 1, there were no behavioral differences between girls and boys, though girls showed stronger prefrontal activation than boys. Study 2 was conducted as an attempt to replicate the results, and some of the results were inconsistent with the results in Study 1. Results suggest that sex differences in EF tasks are small, although such differences may exist irrespective of methodology.

The neurobehavioral relationship between executive function and creativity during early childhood.

Increasing evidence from behavior and neuroimaging research indicates that executive function (EF) is related to creativity. However, most of these studies focused on adult and adolescent populations. The relationship between EF and creativity is unknown when EF undergoes rapid development during early childhood, due to the preschoolers' marginal skills of expressing their ideas, orally or in writing. Using a nonverbal, open-ended test, the present study examined whether creative thinking was related to cognitive flexibility in young children. Preschool children (N = 26) performed the Dimensional Change Card Sort (DCCS) and the Unusual Box Test (UBT), while their brain activation was recorded using functional near-infrared spectroscopy (fNIRS). We did not find any significant correlation between children's cognitive flexibility and creative thinking. However, fNIRS analyses showed that children's brain activation in the lateral prefrontal regions was significantly greater during the test phases of the UBT. Additionally, children who strongly recruited their ventrolateral prefrontal regions during the post-switch phases of the DCCS recruited the same regions while performing the UBT. Taken together, these findings suggest that children recruit their lateral prefrontal regions when expressing creative thinking, and that such creative thinking could be partially supported by cognitive flexibility in early childhood.

Roles of culture and COMT Val58Met gene on neural basis of executive function: A comparison between Japanese and American children.

The development of executive functions (EF) is shaped by both genetic and environmental factors, including cultural background. Genetically, variation in the catechol-O-methyltransferase (COMT) gene polymorphism has been linked to EF performance and differential regulation of prefrontal cortex activity. Based on the gene-culture interaction framework, we tested whether culture would moderate the association between the COMT gene and young children's behavioral responses and neural activities during a cognitive-shifting EF task. The children who participated in this study were 5- to 6-year-olds in Japan (n = 44) and in the U.S. (n = 47). The results revealed that U.S.-American children exhibited stronger activations than Japanese children in the right dorsolateral and bilateral prefrontal cortex regions. In addition, the children's genetic disposition and EF performance were marginally moderated by culture, with Val homozygote Japanese children performing better than Met-allele carriers, whereas no such differences were found in U.S.-American children. We have discussed the theoretical and empirical implications of the construction of a more complete understanding of EF development by incorporating both genetic and socio-cultural factors.

Looking represents choosing in toddlers: Exploring the equivalence between multimodal measures in forced-choice tasks.

In the two-alternative forced-choice (2AFC) paradigm, manual responses such as pointing have been widely used as measures to estimate cognitive abilities. While pointing measurements can be easily collected, coded, analyzed, and interpreted, absent responses are often observed particularly when adopting these measures for toddler studies, which leads to an increase of missing data. Although looking responses such as preferential looking can be available as alternative measures in such cases, it is unknown how well looking measurements can be interpreted as equivalent to manual ones. This study aimed to answer this question by investigating how accurately pointing responses (i.e., left or right) could be predicted from concurrent preferential looking. Using pre-existing videos of toddlers aged 18-23 months engaged in an intermodal word comprehension task, we developed models predicting manual from looking responses. Results showed substantial prediction accuracy for both the Simple Majority Vote and Machine Learning-Based classifiers, which indicates that looking responses would be reasonable alternative measures of manual ones. However, the further exploratory analysis revealed that when applying the created models for data of toddlers who did not produce clear pointing responses, the estimation agreement of missing pointing between the models and the human coders slightly dropped. This indicates that looking responses without pointing were qualitatively different from those with pointing. Bridging two measurements in forced-choice tasks would help researchers avoid wasting collected data due to the absence of manual responses and interpret results from different modalities comprehensively.

Space and rank: infants expect agents in higher position to be socially dominant.

Social hierarchies exist throughout the animal kingdom, including among humans. Our daily interactions inevitably reflect social dominance relationships between individuals. How do we mentally represent such concepts? Studies show that social dominance is represented as vertical space (i.e. high = dominant) by adults and preschool children, suggesting a space-dominance representational link in social cognition. However, little is known about its early development. Here, we present experimental evidence that 12- to 16-month-old infants expect agents presented in a higher spatial position to be more socially dominant than agents in a lower spatial position. After infants repeatedly watched the higher and lower agents being presented simultaneously, they looked longer at the screen when the lower agent subsequently outcompeted the higher agent in securing a reward object, suggesting that this outcome violated their higher-is-dominant expectation. We first manipulated agents' positions by presenting them on a podium (experiment 1). Then we presented the agents on a double-decker stand to make their spatial positions directly above or below each other (experiment 2), and we replicated the results (experiment 3). This research demonstrates that infants expect spatially higher-positioned agents to be socially dominant, suggesting deep roots of the space-dominance link in ontogeny.

Smiling enemies: Young children better recall mean individuals who smile.

Remembering whether a person is cooperative is essential in social interactions. It has been shown that adults have better memory of a person who showed an incongruence between emotional expression and expected behavior (e.g., smiling while stealing). To examine whether children would show similar emotional incongruity effects, we examined 70 children aged 5 or 6 years. They obtained coins that could be exchanged later for rewards (stickers) by answering quiz questions. Then, they participated in the coin collection game where individual persons with smiling or angry expressions appeared one at a time on a computer monitor. These same individuals then either gave coins to or took coins away from the children, leading to congruent (smiling giver and angry taker) and incongruent (smiling taker and angry giver) conditions. After the game, children needed to choose between two faces to indicate which one previously appeared in the game. Participants recognized faces better under the incongruent conditions. In particular, the smiling taker was recognized significantly better than the angry taker, whereas no difference was observed for the smiling and angry givers. Evidently, 5- and 6-year-olds better remember individuals whose facial expression or appearance is incongruent with their expected behavior.

Prevalence of imaginary companions in Japanese children.

Having an imaginary companion (IC) is an example of children's pretend play. However, most research regarding children's ICs is from Western cultures. In this study, the prevalence of ICs was assessed among Japanese children (2- to 9-year-old children, N = 800). The developmental (age), biological (sex), and environmental (birth order) effects on Japanese children's ICs were also assessed. Moreover, whether IC status can be an indicator of fantasy orientation in Japanese children was examined. The results revealed that the prevalence of the invisible friend was relatively rare, but the personified object was prevalent in Japanese children. Age and sex, but not birth order, significantly affected the prevalence of ICs in Japan. Moreover, IC status significantly indicated children's fantasy orientation. The results suggest that the characteristics of Japanese children's ICs are partly different from those in Western children. Social-cultural contexts can affect this difference.

Mind perception of God in Japanese children.

There is a theoretical debate regarding whether children represent God with reference to a human. Most previous studies have assessed this issue focusing on knowledge/omniscience in western children. This study used a theoretical framework characterising mental capacities in terms of motivational/emotional (experience) and cognitive (agency) mental capacities and tested whether Japanese children discriminated between God, a human, a baby and an invisible agent according to these capacities. Three- to 6-year-old children were asked about the experience and agency of the agents. The results revealed that children discriminated God from a human in terms of mental capacities including experience and agency in 3-year-old children. On the other hand, 4- to 6-year-old children, but not 3-year-old children, discriminated a human from a baby and an invisible person. The results suggest that the Japanese children's representations of God differed from their representation of a human during preschool years.

Effect of the COMT Val158Met genotype on lateral prefrontal activations in young children.

Low executive function (EF) during early childhood is a major risk factor for developmental delay, academic failure, and social withdrawal. Susceptible genes may affect the molecular and biological mechanisms underpinning EF. More specifically, genes associated with the regulation of prefrontal dopamine may modulate the response of prefrontal neurons during executive control. Several studies with adults and older children have shown that variants of the catechol-O-methyltransferase (COMT) gene are associated with behavioral performance and prefrontal activations in EF tasks. However, the effect of the COMT genotype on prefrontal activations during EF tasks on young children is still unknown. The present study examined whether a common functional polymorphism (Val158Met) in the COMT gene was associated with prefrontal activations and cognitive shifting in 3- to 6-year-old children. The study revealed that, compared with children with at least one Met allele (Met/Met and Met/Val), children who were Val homozygous (i) were more able to flexibly switch rules in cognitive shifting tasks and (ii) exhibited increased activations in lateral prefrontal regions during these tasks. This is the first evidence that demonstrates the relationship between a gene polymorphism and prefrontal activations in young children. It also indicates that COMT Val homozygosity may be advantageous for cognitive shifting and prefrontal functions, at least during early childhood, and children who possess this variant may have a lower risk of developing future cognitive and social development issues.

Expectations about recipients' prosociality and mental time travel relate to resource allocation in preschoolers.

Previous studies have revealed that preschoolers selectively allocate their resources based on their social relationship with recipients such as friendship. In this investigation, we investigated how expectations about recipients' prosociality and the ability of future thinking relate to the selective allocation of resources. In Study 1, participants aged 3.5-6 years chose how to allocate resources from two ways (selfish allocation, where only the participants could receive stickers, and equal allocation, where the participants and recipients receive get the same number of stickers) in costly and non-costly situations with three recipients (friend, peer, and stranger). Participants were asked to state which alternatives the recipients would choose if they were given a choice. The results showed that children aged 5 and 6 years tended to choose equal allocation of resources when they expected the recipients to do the same both in costly and non-costly situations. This tendency was not observed in children aged 3.5 and 4 years. In Study 2, the relationships between selectivity in non-costly allocation and two facets of future thinking (delay of gratification and mental time travel) were investigated in children aged 5 and 6 years. The results suggested that children with a higher mental time travel ability tended to be more selective in allocating resources based on social relationships; they tended to allocate more resources to the friend and fewer to the peer. Our findings suggest that expectations about a recipient's prosociality and the ability of mental time travel affect selectivity of resource allocation in children aged 5 and 6 years.

Neural correlates of delay of gratification choice in young children: Near-infrared spectroscopy studies.

Delay of gratification refers to the ability to forgo a small immediate reward to obtain a larger delayed reward. Cognitive mechanisms underlying the delay of gratification in young children have been examined extensively. However, the neural mechanism of this process is largely unknown. The present study examined whether inferior prefrontal regions play an important role in the delay of gratification choice paradigm in young children. Preschool children were given a choice version of a delay of gratification task, and their neural activation during the task was assessed using near-infrared spectroscopy in cross-sectional (Study 1) and longitudinal designs (Study 2). Results revealed the activation of the right inferior prefrontal regions of children during the task in both studies. Specifically, the inferior prefrontal regions of the children were activated during immediate choices but not during delay choices. This study is the first to demonstrate the neural correlates of the delay of gratification in young children. We discuss how the right inferior prefrontal regions of preschool children are activated during the delay of gratification.

[Effectiveness of an executive function task with a touch panel system for young children].

The Dimensional Change Card Sort (DCCS) task is a widely used measure for the development of executive function during early childhood. In this task, children are asked to sort cards according to one rule (e.g., color) during preswitch phases, after which they are asked to sort cards according to another rule (e.g.; shape) during the postswitch phases. A computer version of the DCCS was needed to standardize the test material, but a previous study showed that children showed more difficulty in a computer version with a mouse device than the standard card version. In this study, we assessed the effectiveness of a computer version with a touch panel and compared performance with the standard card version. Three- and 4-year-old children were given the card version and computer version of the DCCS tasks. The results revealed that children showed similar performance during the preswitch and postswitch phases both in the computer version and in the card version. The results suggest that both versions of the task assessed the same underlying cognitive processes.