Relationship between maternal grit and effortful control among 18-21-month-old toddlers.

Grit is known to be effective for long-term academic and social success. However, few studies have focused on the role of grit in parenting and its effect on the development of grit in children. Therefore, this study investigated the effect of maternal grit on children's effortful control (EC), which is thought to be a precursor to grit, using parenting as a mediating factor. Participants in the current study were 412 children (age range: 18-21 months, M = 34.67 months, SD = 4.51 months) and their mothers. We assessed maternal grit, parenting style, maternal EC, and child EC, and found that maternal grit, maternal EC, and parenting style were positively correlated with child EC. Furthermore, maternal grit was related to EC in children not only directly, but also indirectly through responsive parenting. Additionally, maternal grit was found to be directly related to child EC only when assessed separately from maternal EC. The current study's findings suggest that maternal grit is directly related to EC in children in a way that differs from the mother's EC in child-rearing situations.

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.

Exploring role of sleep aids in sleep problems in preschool children.

It is well known that children use sleep aids, such as blankets or soft toys, at bedtime. However, there is a lack of understanding regarding the factors associated with their use and role in addressing sleep problems. This study investigated 96 Japanese children aged 40 to 47 months to examine these associations. We measured children's stress (through a questionnaire and salivary cortisol [cortisol awakening response]), anxiety symptoms, behavioral problems, and temperament, and created a model to predict the status of sleep aid use. Furthermore, we explored the association between sleep aid use and children's sleep problems as evaluated by their caregivers. We found that children who used sleep aids were more likely to experience anxiety symptoms. Moreover, most children used sleep aids even when they co-slept with their caregivers and/or siblings. Their use was not uniquely associated with sleep problems. These findings suggest that sleep aid serves as a defense against anxiety, including that caused by the absence of a caregiver, rather than as a substitute for a caregiver. Our study sheds light on their role and emphasizes the importance of viewing development within the complex interactive processes of humans and objects.

Corrigendum: The relationship between children's scale error production and play patterns including pretend play.

[This corrects the article DOI: 10.3389/fpsyg.2020.01776.].

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.

Children's scale errors and object processing: Early evidence for cross-cultural differences.

Scale errors are observed when young children make mistakes by attempting to put their bodies into miniature versions of everyday objects. Such errors have been argued to arise from children's insufficient integration of size into their object representations. The current study investigated whether Japanese and UK children's (18-24 months old, N = 80) visual exploration in a categorization task related to their scale error production. UK children who showed greater local processing made more scale errors, whereas Japanese children, who overall showed greater global processing, showed no such relationship. These results raise the possibility that children's suppression of scale errors emerges not from attention to size per se, but from a critical integration of global (i.e., size) and local (i.e., object features) information during object processing, and provide evidence that this mechanism differs cross-culturally.

Neural Basis of Scale Errors in Young Children.

In this study, we examined whether 2-and 3-year-old children exhibited activation in the dorsolateral and ventrolateral prefrontal regions while engaging in a tool-based scale error task as measured by near-infrared spectroscopy. Results revealed no significant differences in the prefrontal activation between children who produced scale errors and those who did not. However, we found significant activations of the prefrontal region during scale error sessions compared to free play sessions. Our results do not deny that the activation of prefrontal regions may, at least in part, be associated with children's scale error.

The Relationship Between Children's Scale Error Production and Play Patterns Including Pretend Play.

Children of about 2 years of age occasionally make scale errors, e.g., they may attempt to fit their body into extremely small objects. Although previous studies have suggested that immature cognitive abilities may be responsible for these errors, the mechanism of scale error production is unclear. Because we assumed that obtaining characteristics of scale error behavior in the context of play would give us more useful indications concerning individual differences in producing scale errors, we examined how children engage in scale error behavior in relation to other types of play behavior, such as pretending, during the scale error task. The results indicate that children who produced scale errors exhibited less pretend play with miniature toys and tended to refuse to play with miniature toys more often than those who did not produce any scale errors during the task. Moreover, among the children who produced scale errors, the children who produced more scale errors were less likely to touch the miniature objects and less likely to perform pretending actions than those who produced fewer scale errors. These results suggest that pretense play is deeply related to a lower production, or no production, of scale errors. Some immature cognitive abilities underlining pretense play can be assumed to be related to the production of scale error. In conclusion, this study is one of the first to demonstrate empirically significant relationships between children's scale error production and pretend behaviors, although further studies are necessary to understand the mechanisms.

Understanding Why Children Commit Scale Errors: Scale Error and Its Relation to Action Planning and Inhibitory Control, and the Concept of Size.

Scale error is a phenomenon where young children attempt to perform inappropriate actions on miniature object without considering the actual size of the object. The present study examined two hypotheses on what factors contribute to the occurrence of scale errors, focusing on the following possible factors: action planning and inhibitory control, and concept of size. Thus, we hypothesize that scale errors derived from either immaturity of their action planning and inhibitory control abilities or understanding of size concepts. The results revealed that the concept of size was significantly negatively associated with the occurrence of scale errors. However, action planning and inhibitory control were not significantly associated with the occurrence of scale errors. These results suggest that scale errors may arise from a misunderstanding of size concepts.

Teaching others rule-use improves executive function and prefrontal activations in young children.

Intervention of executive function during early childhood is an important research topic. This study examined the effect of a child-friendly intervention program, where children interacted with a doll or a puppet. Children were presented with cognitive shifting tasks before and after an intervention. In the intervention, children interacted with a doll or a puppet, and taught rules of the cognitive shifting tasks to the object. As the results, 3- to 5-year-old children significantly improved the performances and strengthened activations in the lateral prefrontal regions as measured by near-infrared spectroscopy. The results suggest that interaction with a doll or a puppet may have a significant impact on the development of executive function.