Infants who are rarely spoken to nevertheless understand many words.

Theories of language development-informed largely by studies of Western, middleclass infants-have highlighted the language that caregivers direct to children as a key driver of language learning. However, some have argued that language development unfolds similarly across environmental contexts, including those in which childdirected language is scarce. This raises the possibility that children are able to learn from other sources of language in their environments, particularly the language directed to others in their environment. We explore this hypothesis with infants in an indigenous Tseltal-speaking community in Southern Mexico who are rarely spoken to, yet have the opportunity to overhear a great deal of other-directed language by virtue of being carried on their mothers' backs. Adapting a previously established gaze-tracking method for detecting early word knowledge to our field setting, we find that Tseltal infants exhibit implicit knowledge of common nouns (Exp. 1), analogous to their US peers who are frequently spoken to. Moreover, they exhibit comprehension of Tseltal honorific terms that are exclusively used to greet adults in the community (Exp. 2), representing language that could only have been learned through overhearing. In so doing, Tseltal infants demonstrate an ability to discriminate words with similar meanings and perceptually similar referents at an earlier age than has been shown among Western children. Together, these results suggest that for some infants, learning from overhearing may be an important path toward developing language.

Disagreement reduces overconfidence and prompts exploration in young children.

Can the experience of disagreement lead young children to reason in more sophisticated ways? Across two preregistered studies, four- to six-year-old US children (N = 136, 50% female, mixed ethnicities, data collected 2020-2022) experienced either a disagreement or an agreement with a confederate about a causal mechanism after being presented with ambiguous evidence. We measured (1) children's confidence in their belief before and after the (dis)agreement, and (2) how long children searched for information about the correct answer. Disagreement, especially with an expert (Experiment 2), reduced overconfidence and prompted children to search longer for information, compared to agreement. Together, our findings suggest possibilities for interventions aimed at fostering humility and learning across the lifespan.

Developmental psychologists should adopt citizen science to improve generalization and reproducibility.

Widespread failures of replication and generalization are, ironically, a scientific triumph, in that they confirm the fundamental metascientific theory that underlies our field. Generalizable and replicable findings require testing large numbers of subjects from a wide range of demographics with a large, randomly-sampled stimulus set, and using a variety of experimental parameters. Because few studies accomplish any of this, meta-scientists predict that findings will frequently fail to replicate or generalize. We argue that to be more robust and replicable, developmental psychology needs to find a mechanism for collecting data at greater scale and from more diverse populations. Luckily, this mechanism already exists: Citizen science, in which large numbers of uncompensated volunteers provide data. While best-known for its contributions to astronomy and ecology, citizen science has also produced major findings in neuroscience and psychology, and increasingly in developmental psychology. We provide examples, address practical challenges, discuss limitations, and compare to other methods of obtaining large datasets. Ultimately, we argue that the range of studies where it makes sense *not* to use citizen science is steadily dwindling.

Structural explanations lead young children and adults to rectify resource inequalities.

Decisions about how to divide resources have profound social and practical consequences. Do explanations regarding the source of existing inequalities influence how children and adults allocate new resources? When 3- to 6-year-old children (N = 201) learned that inequalities were caused by structural forces (stable external constraints affecting access to resources) as opposed to internal forces (effort), they rectified inequalities, overriding previously documented tendencies to perpetuate inequality or divide resources equally. Adults (N = 201) were more likely than children to rectify inequality spontaneously; this was further strengthened by a structural explanation but reversed by an effort-based explanation. Allocation behaviors were mirrored in judgments of which allocation choices by others were appropriate. These findings reveal how explanations powerfully guide social reasoning and action from childhood through adulthood.

The development and diversity of religious cognition and behavior: Protocol for Wave 1 data collection with children and parents by the Developing Belief Network.

The Developing Belief Network is a consortium of researchers studying human development in diverse social-cultural settings, with a focus on the interplay between general cognitive development and culturally specific processes of socialization and cultural transmission in early and middle childhood. The current manuscript describes the study protocol for the network's first wave of data collection, which aims to explore the development and diversity of religious cognition and behavior. This work is guided by three key research questions: (1) How do children represent and reason about religious and supernatural agents? (2) How do children represent and reason about religion as an aspect of social identity? (3) How are religious and supernatural beliefs transmitted within and between generations? The protocol is designed to address these questions via a set of nine tasks for children between the ages of 4 and 10 years, a comprehensive survey completed by their parents/caregivers, and a task designed to elicit conversations between children and caregivers. This study is being conducted in 39 distinct cultural-religious groups (to date), spanning 17 countries and 13 languages. In this manuscript, we provide detailed descriptions of all elements of this study protocol, give a brief overview of the ways in which this protocol has been adapted for use in diverse religious communities, and present the final, English-language study materials for 6 of the 39 cultural-religious groups who are currently being recruited for this study: Protestant Americans, Catholic Americans, American members of the Church of Jesus Christ of Latter-day Saints, Jewish Americans, Muslim Americans, and religiously unaffiliated Americans.

Children's developing ability to adjust their beliefs reasonably in light of disagreement.

Two preregistered experiments (N = 218) investigated children's developing ability to respond reasonably to disagreement. U.S. children aged 4-9, and adults (50% female, mostly white) formed an initial belief, and were confronted with the belief of a disagreeing other, whose evidence was weaker, stronger than, or equal to participants' evidence. With age, participants were increasingly likely to maintain their initial belief when their own evidence was stronger, adopt the other's belief when their evidence was weaker, and suspend judgment when both had equally strong evidence. Interestingly, 4- to 6-year-olds only suspended judgment reliably when this was assessed via the search for additional information (Experiment 2). Together, our experiments suggest that the ability to respond reasonably to disagreement develops over the preschool years.

Children's use of pragmatic inference to learn about the social world.

Young children often endorse stereotypes-such as "girls are bad at math." We explore one mechanism through which these beliefs may be transmitted: via pragmatic inference. Specifically, we ask whether preschoolers and adults can learn about an unmentioned social group from what is said about another group, and if this inferential process is sensitive to the context of the utterance. Sixty-three- to five-year-old children and fifty-five adults were introduced to two novel social groups-Stripeys and Dotties-and witnessed a speaker praising abilities of one group (e.g., "the Stripeys are good at building chairs"). To examine the effect of context, we compared situations where the speaker was knowledgeable about the abilities of both groups, and had been queried about the performance of both groups (broad context), versus situations where the speaker was only knowledgeable about one group and was only asked about that group (narrow context). Both preschoolers and adults were sensitive to context: they were more likely to infer that the group not mentioned by the speaker was relatively unskilled, and were more confident about it, in the broad context condition. Our work integrates research in language development and social cognitive development and demonstrates that even young children can "read between the lines," utilizing subtle contextual cues to pick up negative evaluative messages about social groups even from statements that ostensibly do not mention them at all. HIGHLIGHTS: After hearing a speaker praise one group's skill, preschoolers and adults infer that an unmentioned group is relatively less skilled across a range of measures. These inferences are context-sensitive and are stronger when the speaker is knowledgeable of and asked about both groups' skill level. These results shed light on how children may indirectly learn negative stereotypes, especially ones that adults are unlikely to state explicitly. This work extends previous research on children's developing pragmatic ability, as well as their ability to learn about the social world from language.

Crossing religious boundaries: Individual and contextual determinants of who can violate religious norms.

In pluralistic societies, encounters with individuals, contexts, and norms of other religions can prompt conflict. We test a novel framework for explaining how individuals apply religious norms across individuals and contexts. In Studies 1 and 2, adolescents and adults in India and the United States judged events in which religious norms were violated by protagonists of different religions in different religious contexts. Participants often judged that norm violations were wrong even when the norm religion matched only the protagonist or context religion. Study 3 presented dilemmas that pitted religious norms against non-religious concerns. Participants favored following the religious norm yet accepted the protagonist's right to violate it. In each adult sample, more religious participants more often judged that protagonists were obligated to follow the protagonist's own religious norms. These findings reveal individual and contextual determinants of judgments about religious violations with implications for peaceful coexistence in pluralistic societies.

Preschoolers learn new moral and conventional norms from direct experiences.

By observing others, children can learn about different types of norms, including moral norms rooted in concerns for welfare and rights, and social conventions based on directives from authority figures or social consensus. Two experiments examined how preschoolers and adults constructed and applied knowledge about novel moral and conventional norms from their direct social experiences. Participants watched a video of a novel prohibited action that caused pain to a victim (moral conditions) or a sound from a box (conventional conditions). Next, they saw a transgressor puppet, who had either watched the video alongside participants or not, engage in the prohibited action. Preschoolers and adults rapidly constructed distinct moral and conventional evaluations about the novel actions. These distinctions were evident across several response modalities that have often been studied separately, including judgments, reasoning, and actions. However, children did not reliably track the puppet's knowledge of the novel norms. These studies provide experimental support for the idea that children and adults construct distinct moral and conventional norms from social experiences, which in turn guide judgments, reasoning, and behavior.

What causes the word gap? Financial concerns may systematically suppress child-directed speech.

Parents with fewer educational and economic resources (low socioeconomic-status, SES) tend to speak less to their children, with consequences for children's later life outcomes. Despite this well-established and highly popularized link, less research addresses why the SES "word gap" exists. Moreover, while research has assessed individual-level contributors to the word gap-like differences in parenting knowledge-we know little about how structural constraints that vary according to SES might affect caregivers' speech. In two pre-registered studies, we test whether experiencing financial scarcity can suppress caregivers' speech to their children. Study 1 suggests that higher-SES caregivers who are prompted to reflect on scarcity-particularly those who reflect on financial scarcity-speak less to their 3-year-olds in a subsequent play session, relative to a control group. Study 2 suggests that mid- to higher-SES caregivers engage in fewer back-and-forth exchanges with their children at the end of the month-when they are more likely to be experiencing financial hardship-than the rest of the month. These studies provide preliminary evidence that-above and beyond caregivers' individual characteristics-structural constraints may affect how much parents speak to their children.

The future is in front, to the right, or below: Development of spatial representations of time in three dimensions.

Across cultures, people frequently communicate about time in terms of space. English speakers in the United States, for example, might "look forward" to the future or gesture toward the left when talking about the past. As shown by these examples, different dimensions of space are used to represent different temporal concepts. Here, we explored how cultural factors and individual differences shape the development of two types of spatiotemporal representations in 6- to 15-year-old children: the horizontal/vertical mental timeline (in which past and future events are placed on a horizontal or vertical line that is external to the body) and the sagittal mental timeline (in which events are placed on a line that runs through the front-back axis of the body). We tested children in India because the prevalence of both horizontal and vertical calendars there provided a unique opportunity to investigate how calendar orientation and writing direction might each influence the development of the horizontal/vertical mental timeline. Our results suggest that the horizontal/vertical mental timeline and the sagittal mental timeline are constructed in parallel throughout childhood and become increasingly aligned with culturally-conventional orientations. Additionally, we show that experience with calendars may influence the orientation of children's horizontal/vertical mental timelines, and that individual differences in children's attitudes toward the past and future may influence the orientation of their sagittal mental timelines. Taken together, our results demonstrate that children are sensitive to both cultural and personal factors when building mental models of time.

Self-directed learning by preschoolers in a naturalistic overhearing context.

Three studies investigated preschoolers' self-directed learning ability in a naturalistic context: learning from overheard speech. In Experiment 1, 4.5- to 6-year-olds were exposed to 4 novel words and 6 arbitrary facts corresponding to a set of co-present toys; in Experiment 2, 3- to 4.5-year-olds heard 5 nouns and 3 facts. In the Pedagogical conditions, children were taught the information with the aid of multiple pedagogical cues, but in the Overhearing conditions, children had to 'listen in' to one side of a phone call to learn the information. Older preschoolers (Experiment 1) learned all items above chance in both conditions. Younger preschoolers (Experiment 2) learned words and facts above chance in the Pedagogical condition, but were at chance at learning words in the Overhearing condition, despite reliably learning facts from overhearing. Experiment 3 demonstrated that younger children's difficulty at learning new words from overhearing could not be explained by only being able to hear one side of the phone conversation, as they similarly struggled when the phone call took place over speakerphone. Measures of children's touch behavior suggest that older children were better able to coordinate their attention between the overheard speech and objects, though even younger children showed evidence of attention to the overheard speech. Together, our results demonstrate that by age 5, children can learn multiple new words and facts via overhearing. This self-directed learning ability depends on being able to coordinate attention between speech and the surrounding environment, a capacity that develops throughout preschool.

Spatial Metaphor Facilitates Word Learning.

Why are spatial metaphors, like the use of "high" to describe a musical pitch, so common? This study tested one hundred and fifty-four 3- to 5-year-old English-learning children on their ability to learn a novel adjective in the domain of space or pitch and to extend this adjective to the untrained dimension. Children were more proficient at learning the word when it described a spatial attribute compared to pitch. However, once children learned the word, they extended it to the untrained dimension without feedback. Thus, children leveraged preexisting associations between space and pitch to spontaneously understand new metaphors. These results suggest that spatial metaphors may be common across languages in part because they scaffold children's acquisition of word meanings that are otherwise difficult to learn.

Semantic knowledge influences visual working memory in adults and children.

We can retain only a portion of the visual information that we encounter within our visual working memory. Which factors influence how much information we can remember? Recent studies have demonstrated that the capacity of visual working memory is influenced by the type of information to be remembered and is greater for real-world objects than for abstract stimuli. One explanation for this effect is that the semantic knowledge associated with real-world objects makes them easier to maintain in working memory. Previous studies have indirectly tested this proposal and led to inconsistent conclusions. Here, we directly tested whether semantic knowledge confers a benefit for visual working memory by using familiar and unfamiliar real-world objects. We found a mnemonic benefit for familiar objects in adults and children between the ages of 4 and 9 years. Control conditions ruled out alternative explanations, namely the possibility that the familiar objects could be more easily labeled or that there were differences in low-level visual features between the two types of objects. Together, these findings demonstrate that semantic knowledge influences visual working memory, which suggests that the capacity of visual working memory is not fixed but instead fluctuates depending on what has to be remembered.

Conceptual relations predict colexification across languages.

In natural language, multiple meanings often share a single word form, a phenomenon known as colexification. Some sets of meanings are more frequently colexified across languages than others, but the source of this variation is not well understood. We propose that cross-linguistic variation in colexification frequency is non-arbitrary and reflects a general principle of cognitive economy: More commonly colexified meanings across languages are those that require less cognitive effort to relate. To evaluate our proposal, we examine patterns of colexification of varying frequency from about 250 languages. We predict these colexification data based on independent measures of conceptual relatedness drawn from large-scale psychological and linguistic resources. Our results show that meanings that are more frequently colexified across these languages tend to be more strongly associated by speakers of English, suggesting that conceptual associativity provides an important constraint on the development of the lexicon. Our work extends research on polysemy and the evolution of word meanings by grounding cross-linguistic regularities in colexification in basic principles of human cognition.

Why do bilinguals code-switch when emotional? Insights from immigrant parent-child interactions.

Previous research has found that bilingual speakers' first (L1) and second languages (L2) are differentially associated with their emotional experiences. Moreover, bilinguals appear to code-switch (alternate between two or more languages in a single conversation) during emotional episodes. However, prior evidence has been limited to clinical case studies and self-report studies, leaving open the specificity of the link between code-switching (CS) and emotion and its underlying mechanisms. The present study examined the dynamic associations between CS and facial emotion behavior in a sample of 68 Chinese American parents and children during a dyadic emotion-inducing puzzle box task. Specifically, bilingual parents' language use (L1 Chinese or L2 English), CS behavior (L1→L2 or L2→L1 switches), and facial emotion behavior (positive and negative valence) were coded at each 5-s interval. Multilevel modeling was used to analyze whether facial emotion behavior predicted later CS and vice versa. We found that negative facial emotion predicted higher subsequent CS in both L1→L2 and L2→L1 directions, with stronger associations for the L2→L1 direction. On the other hand, positive facial emotion was associated with lower contemporaneous L2→L1 CS. CS did not predict later facial emotion behavior, suggesting language switching may not have an immediate effect on emotion. The present findings are consistent with the idea that emotional arousal, especially negative arousal, reduces cognitive control and may trigger spontaneous CS. Together, these findings provide insight into why bilingual speakers switch languages during emotional episodes and hold implications for clinical interventions serving bilingual individuals and families. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Indian = Hindu? The Development of Nationalist Attitudes Among Hindu and Muslim Children in India.

Many political movements across the world today define citizenship in exclusionary ethnic or religious terms. This study extends research on ethnic-national associations in adults to children, adding to the relatively sparse literature on the development of national associations in children and in nonwestern contexts. Explicit and implicit religious-national associations were examined in a sample of 160 nine- to sixteen-year-olds (79 Hindu; 81 Muslim) in Gujarat, India. Results suggest that while Hindu children show a strong Indian = Hindu association by age 9, Muslim children appear to be buffered from this association. Furthermore, this association uniquely predicts variance in children's attitudes about social policy and their concept of nationality, above and beyond their age, religion, and intergroup attitudes.

Measuring subjective social status in children of diverse societies.

Subjective Social Status (SSS) is a robust predictor of psychological and physiological outcomes, frequently measured as self-reported placement on the MacArthur Scale of Subjective Social Status. Despite its importance, however, there are still open questions regarding how early into ontogeny SSS can be measured, and how well SSS measures can be extended to non-Western and small-scale populations. Here, we investigate the internal consistency of responses to the MacArthur ladder across four cultures by comparing responses to more explicit social comparison questions. We conduct these comparisons among children and adolescents, ages 4 to 18, in India, the United States, and Argentina, in addition to those in two indigenous communities of the Ecuadorean Amazon marked by differing degrees of market integration (total N = 363). We find that responses are consistent in all populations, except for the more remote forager-horticulturalist Ecuadorian community. We also find that, consistent with findings among American adolescents, SSS declines with age. We then assess the test-retest reliability of the MacArthur Scale across two time-points: a subset of Indian participants (N = 43) within one week, and a larger, second sample of Indian participants after one year (N = 665). We find that responses are highly correlated within one week (ρ = 0.47), and moderately correlated after one year (ρ = 0.32). These results suggest that responses to the MacArthur ladder are internally consistent and reliable among children across a range of diverse populations, though care must be taken in utilizing these measures among children of non-industrial, small-scale societies.

Linguistic conventionality and the role of epistemic reasoning in children's mutual exclusivity inferences.

To interpret an interlocutor's use of a novel word (e.g., "give me the papaya"), children typically exclude referents that they already have labels for (like an "apple"), and expect the word to refer to something they do not have a label for (like the papaya). The goal of the present studies was to test whether such mutual exclusivity inferences require children to reason about the words their interlocutors know and could have chosen to say: e.g., If she had wanted the "apple" she would have asked for it (since she knows the word "apple"), so she must want the papaya. Across four studies, we document that both children and adults will make mutual exclusivity inferences even when they believe that their interlocutor does not share their knowledge of relevant, alternative words, suggesting that such inferences do not require reasoning about an interlocutor's epistemic states. Instead, our findings suggest that children's own knowledge of an object's label, together with their belief that this is the conventional label for the object in their language, and that this convention applies to their interlocutor, is sufficient to support their mutual exclusivity inferences. Additionally, and contrary to the claims of previous studies that have used mutual exclusivity as a proxy for children's beliefs that others share their knowledge, we found that children - especially those with stronger theory of mind ability - are quite conservative about attributing their knowledge of object labels to others. Together, our findings hold implications for theories of word learning, and for how children learn about the scope of shared conventional knowledge.

Reasoning About the Scope of Religious Norms: Evidence From Hindu and Muslim Children in India.

Conflicts arise when members of one religion apply their norms to members of another religion. Two studies explored how one hundred 9- to 15-year-old Hindu and Muslim children from India reason about the scope of religious norms. Both Hindus and Muslims from a diverse Hindu-Muslim school (Study 1) and Hindus from a homogeneous Hindu school (Study 2) more often judged it wrong for Hindus to violate Hindu norms, compared to Muslim norms, and said the opposite for Muslims. In contrast, children judged it wrong for both Hindus and Muslims to harm others. Thus, even in a setting marred by religious conflict, children can restrict the scope of a religion's norms to members of that religion, providing a basis for peaceful coexistence.