When does the ability to reason about alternative possibilities emerge during cognitive development? This has been a matter of considerable dispute. Conservative accounts assume that modal reasoning emerges relatively late, not before age 4 (Carey et al., 2020). Evidence for these accounts comes from tasks where children fail to take into account mutually incompatible possibilities. However, it is unclear whether these failures truly reflect competence deficits, or rather performance limitations. One recent suggestion is that modal reasoning tasks are mastered earlier if children need to deliberate about which outcome they could bring about rather than respond to events beyond their control (Phillips & Kratzer, 2024). The present studies tested this suggestion. In Study 1, 3- and 4-year-old children received tasks in which they could exert agentive control over the realization of the outcome: they chose between performing an action that must lead to a reward and an action that might lead to a reward. Study 2 examined whether children's performance is influenced by superficial task factors, by the type of agentive modality (acting oneself vs. directing someone else's action), and by the type of uncertainty (reasoning about what could be the case in the future vs. what could be the case at present, but is (still) unknown). Results indicate that even 3-year-olds perform competently in some tasks where they control the outcome. Altogether, our findings suggest that modal reasoning competences can be masked by performance factors under certain circumstances.

Do mono- and bilingual children differ in the way they learn novel words in ambiguous settings? Listeners may resolve referential ambiguity by assuming that novel words refer to unknown, rather than known, objects –a response known as the mutual exclusivity effect. Past research suggested that mono- and bilinguals differ with regard to this disambiguation strategy, perhaps because, across languages, bilinguals’ experience contradicts one-to-one mappings of label and referent. Another line of research suggested a bilingual advantage in resolving referential ambiguity, based on bilinguals’ advanced pragmatic skills. Here, we examine both these claims in a preregistered study with comparable samples of mono- and bilingual 3-year-olds (n=74) and adults (n=86). We tested referent disambiguation and retention in two tasks: In the Mutual-Exclusivity task, a speaker used a novel label in the presence of a known and an unknown object. In the Pragmatic task, she used another novel label in the presence of two unknown objects and participants could infer from the pragmatic context that the speaker referred to the object that was new in their discourse. Mono- and bilinguals were equally successful in inferring the correct label-referent links in both tasks and retained them after a delay. These findings indicate that children with different language backgrounds can develop the same strategies and pragmatic skills to learn novel words. Children can use their lexical knowledge and socio-cognitive skills to infer the meanings of novel words, irrespective of whether they are acquiring one or more languages.

Do mono- and bilingual children differ in the way they learn novel words in ambiguoussettings? Listeners may resolve referential ambiguity by assuming that novel words refer tounknown, rather than known, objects –a response known as the mutual exclusivity effect. Pastresearch suggested a bilingual disadvantage with regard to this disambiguation strategy,perhaps because, across languages, bilinguals’ experience contradicts one-to-one mappings oflabel and referent. Another line of research suggested a bilingual advantage in resolvingreferential ambiguity, based on bilinguals’ advanced pragmatic skills. Here, we examine boththese claims in a preregistered study with comparable samples of mono- and bilingual 3-yearolds(n=74) and adults (n=86). We tested referent disambiguation and retention in two tasks:In the Mutual-Exclusivity task, a speaker used a novel label in presence of a known and anunknown object. In the Pragmatic task, she used another novel label in presence of twounknown objects and participants could infer from the pragmatic context that the speakerreferred to the object that was new in their discourse. Mono- and bilinguals were equallysuccessful in inferring the correct label-referent links in both tasks and retained them after adelay. These findings indicate that children with different language backgrounds can developthe same strategies and pragmatic skills to learn novel words, highlighting the importance oftesting comparable samples of mono- and bilinguals. Children can use their lexical knowledgeand socio-cognitive skills to infer the meanings of novel words, irrespective of whether theyare acquiring one or more languages.

Much research has demonstrated preschoolers’ selective trust in reliable over unreliable sources, but it is debated what cognitive underpinnings mediate this selectivity (low-level attentional biases or higher-level trait ascriptions) and whether children younger than 3 years show selective trust in reliable over unreliable speakers. To address these issues, we adapted a version of the standard two-informant test for younger children and tested 2- and 5-year-olds in the same paradigm, using both eye-tracking and interactive measures. Thus, we could examine whether children’s selective trust was predicted by an attentional bias to the more reliable speaker and whether toddlers, like preschoolers, selectively endorse the contested information provided by the more reliable source. Our findings suggest that children’s selective learning of novel labels is not based on inattention towards the information provided by unreliable source, but rather on the selective encoding and consolidation of the semantic information provided by a more reliable source. Whereas 5-year-olds demonstrated selective trust across a range of tasks and measures, 2-year-olds showed no evidence of selectively learning novel labels from the more reliable source. If the two speakers provided conflicting information, toddlers performed at chance level, rather than selectively endorsing the information by the more reliable source. However, in a follow-up study that presented the same word-learning demands, but no need to consider the speakers’ respective reliability, 2-year-olds showed successful learning of novel labels. Thus, toddlers seemed to have struggled with making person-specific attribution of reliability rather than with the tasks’ word learning demands.

Upon hearing a novel label, listeners tend to assume that it refers to a novel, rather than a familiar object. While this disambiguation or mutual exclusivity (ME) effect has been robustly shown across development, it is unclear what it involves. Do listeners use their pragmatic and lexical knowledge to exclude the familiar object and thus select the novel one? Or is the effect, at least in early childhood, simply based on an attraction to novelty and a direct mapping of the novel label to a novel object? In a pre-registered online-study with 2-to-3-year-olds (n=75) and adults (n=112), we examined i) whether relative object novelty alone (without pragmatic or lexical information) could account for participants’ disambiguation and ii) whether participants’ decision processes involved reasoning-by-exclusion. Participants encountered either a known and an unknown object (classic ME condition) or two unknown objects, one completely novel and one pre-exposed (novelty condition) as potential referents of a novel label. Reasoning-by-exclusion was assessed by children’s looking patterns and adults’ explanations. In the classic ME condition, children and adults significantly chose the novel object and both used reasoning-by-exclusion. In contrast, in the novelty condition, children and adults chose randomly. Across conditions, a retention test revealed that adults remembered their prior selections, while children’s performance was fragile. These results suggest that referent disambiguation is not based on relative object novelty alone. Instead, to resolve referential ambiguity, both young children and adults seem to make use of pragmatic and/or lexical sources of information and to engage in reasoning-by-exclusion strategies.

How do children succeed in learning a word? Research has shown robustly that, in ambiguous labeling situations, young children assume novel labels to refer to unfamiliar rather than familiar objects. However, ongoing debates center on the underlying mechanism: Is this behavior based on lexical constraints, guided by pragmatic reasoning, or simply driven by children's attraction to novelty? Additionally, recent research has questioned whether children's disambiguation leads to long-term learning or rather indicates an attentional shift in the moment of the conversation. Thus, we conducted a pre-registered online study with 2- and 3-year-olds and adults. Participants were presented with unknown objects as potential referents for a novel word. Across conditions, we manipulated whether the only difference between both objects was their relative novelty to the participant or whether, in addition, participants were provided with pragmatic information that indicated which object the speaker referred to. We tested participants' immediate referent selection and their retention after 5 min. Results revealed that when given common ground information both age groups inferred the correct referent with high success and enhanced behavioral certainty. Without this information, object novelty alone did not guide their selection. After 5 min, adults remembered their previous selections above chance in both conditions, while children only showed reliable learning in the pragmatic condition. The pattern of results indicates how pragmatics may aid referent disambiguation and learning in both adults and young children. From early ontogeny on, children's social-cognitive understanding may guide their communicative interactions and support their language acquisition. RESEARCH HIGHLIGHTS: We tested how 2-3-year-olds and adults resolve referential ambiguity without any lexical cues. In the pragmatic context both age groups disambiguated novel word-object-mappings, while object novelty alone did not guide their referent selection. In the pragmatic context, children also showed increased certainty in disambiguation and retained new word-object-mappings over time. These findings contribute to the ongoing debate on whether children learn words on the basis of domain-specific constraints, lower-level associative mechanisms, or pragmatic inferences.

The current study investigates infants' and toddlers' understanding of teasing interactions and its effect on subsequent social interactions. Teasing is a special kind of social interaction due to its dual nature: It consists of a slightly provocative contingent action accompanied by positive ostensive emotional cues. Teasing thus presents an especially interesting test case to inform us about young children's abilities to deal with complex social intentions. In a first experiment, we looked at 9-, 12-, and 18-month-old infants' ability to understand and differentiate a teasing intention from a trying intention and a refuse intention. We found that by 12 months of age, infants react differently (gaze, reach) and by 18 months they smile more in reaction to the Tease condition. In the second experiment, we tested 13-, 20- and 30-month-old children in closely matched purely playful and teasing situations. We also investigated potential social effects of teasing interactions on a subsequent affiliation sequence. Twenty- and 30-month-old children smile more in the Teasing than in the Play condition. For the 30-month-old toddlers, additionally, number of laughs is much higher in the Tease than in the Play condition. No effect on affiliation could be found. Thus, from very early in development, infants and toddlers are able to differentiate teasing from superficially similar but serious behavior and from around 18 months of age they enjoy it more. Infants and toddlers are able to process a complex social intention like teasing. Findings are discussed regarding infant and toddler intention understanding abilities.

The current study set out to examine the underlying physiological mechanisms of and the emotional response associated with word learning success in young 3-year-old predominantly white children. In particular, we examined whether children’s physiological arousal following a word learning task predicts their word learning success and whether successful learning in turn predicts children’s subsequent positive emotions. We presented children (n = 50) with a cross-situational word learning task and measured their pupillary arousal following completion of the task, as well as changes to their upper body posture following completion of the task, as indices of children’s emotions following task completion. Children who showed greater physiological arousal following the novel word recognition task (n = 40) showed improved subsequent word recognition performance. We found that children showed more elevated posture after completing a familiar word learning task compared to completing a novel word learning task (n = 33) but results on children’s individual learning success and postural elevation were mixed. We discuss the findings with regards to children’s affective involvement in word learning.

When dogs interact with humans, they often show appropriate reactions to human intentional action. But it is unclear from these everyday observations whether the dogs simply respond to the action outcomes or whether they are able to discriminate between different categories of actions. Are dogs able to distinguish intentional human actions from unintentional ones, even when the action outcomes are the same? We tested dogs' ability to discriminate these action categories by adapting the so-called "Unwilling vs. Unable" paradigm. This paradigm compares subjects' reactions to intentional and unintentional human behaviour. All dogs received three conditions: In the unwilling-condition, an experimenter intentionally withheld a reward from them. In the two unable-conditions, she unintentionally withheld the reward, either because she was clumsy or because she was physically prevented from giving the reward to the dog. Dogs clearly distinguished in their spontaneous behaviour between unwilling- and unable-conditions. This indicates that dogs indeed distinguish intentional actions from unintentional behaviour. We critically discuss our findings with regard to dogs' understanding of human intentional action.

Caregivers typically use an exaggerated speech register known as infant-directed speech (IDS) in communication with infants. Infants prefer IDS over adult-directed speech (ADS) and IDS is functionally relevant in infant-directed communication. We examined interactions among maternal IDS quality, infants' preference for IDS over ADS, and the functional relevance of IDS at 6 and 13 months. While 6-month-olds showed a preference for IDS over ADS, 13-month-olds did not. Differences in gaze following behavior triggered by speech register (IDS vs. ADS) were found in both age groups. The degree of infants' preference for IDS (relative to ADS) was linked to the quality of maternal IDS infants were exposed to. No such relationship was found between gaze following behavior and maternal IDS quality and infants' IDS preference. The results speak to a dynamic interaction between infants' preference for different kinds of social signals and the social cues available to them.

Young children learn selectively from others based on the speakers' prior accuracy. This indicates that they recognize the models’ (in)competence and use it to predict who will provide the most accurate and useful information in the future. Here, we investigated whether 5-year-old children are also able to use speaker reliability retrospectively, once they have more information regarding their competence. They first experienced two previously unknown speakers who provided conflicting information about the referent of a novel label, with each speaker using the same novel label to refer exclusively to a different novel object. Following this, children learned about the speakers' differing labelling accuracy. Subsequently, children selectively endorsed the object–label link initially provided by the speaker who turned out to be reliable significantly above chance. Crucially, more than half of these children justified their object selection with reference to speaker reliability, indicating the ability to explicitly reason about their selective trust in others based on the informants’ individual competences. Findings further corroborate the notion that young children are able to use advanced, metacognitive strategies (trait reasoning) to learn selectively. By contrast, since learning preceded reliability exposure and gaze data showed no preferential looking toward the more reliable speaker, findings cannot be accounted for by attentional bias accounts of selective social learning.

Research has shown that young children are selective in whom they trust, for example, learning selectively from more reliable sources. To explain what cognitive foundations this capacity may build upon, a recent dual-process account proposed that children recruit different kinds of cognitive strategies, including a) simple heuristics, e.g., favoring protagonists that are overall better or score high on a salient, accessible characteristic, and b) more systematic strategies, e.g., taking into account the protagonists’ individual properties. The present studies investigated the prediction that the more systematic processes require cognitive resources and develop with age. Children and adults were familiarized with two protagonists: The strong-and-shy protagonist scored high on a highly accessible trait (strength), whereas the weak-and-extraverted protagonist scored high on a less accessible trait (extraversion). In test trials, participants chose between these for strength- and extraversion-related tasks. The results were consistent with the prediction of the dual-process account: Older children, and adults under normal conditions, showed a pattern of systematic reasoning, selecting the protagonists with the relevant trait for a given task. Yet, younger children, and adults whose cognitive capacities were burdened with a secondary task, showed a pattern of heuristic reasoning, selecting the strong-and-shy protagonist for all kinds of tasks.

concepts such as time and number are mentally represented in space. A common representation of numerals, e. g. in Western European adults, is the horizontal number line with smaller digits to the left of larger digits. Similarly, temporal information can be represented horizontally with temporally earlier events or shorter durations to the left of temporally later events or longer durations. There is additional evidence that temporal information might be represented relative to the body axes (sagittal, lateral) as well. This project investigates spatial representations of different temporal and numerical categories on body axes and coordinate axes. Using a behavioral paradigm, children’s and adults’ spontaneous spatial allocations of items that represent temporal or numerical relations are recorded. Spatial allocations are analyzed in terms of linearity, ordinality, and direction in order to compare dominant representations between concepts and across different age groups.

Much recent research has shown that children from age 4 onwards reveal a robust preference for reliable over unreliable informants when choosing whom to trust and learn from. Findings concerning selective model choice in children younger than 4 years have mostly been mixed. The present study developed a new touchscreen-based paradigm with reduced task demands in order to test 2- and 3-year-old children (N = 48). Results showed that 3-year-olds selectively endorsed information from a previously reliable rather than a previously unreliable informant when searching for objects whereas 2-year-olds just followed the first hint even if provided by an unreliable informant. Whether the lack of selective model choice in 2-year-olds reflects competence or performance deficits remains to be clarified. But the present results do suggest that 3-years-olds have the basic competence to selectively choose reliable over unreliable informants that may have been masked in some previous studies by task demands.

From the point of view of cognitive development, the present paper by Bart Geurts is highly relevant, welcome and timely. It speaks to a fundamental puzzle in developmental pragmatics that used to be seen as such, then was considered to be resolved by many researchers, but may return nowadays with its full puzzling force. The puzzle in question is the following: on broadly Gricean accounts, how should young children ever be able to start communicating, given that even basic conversation requires heavy cognitive machinery of recursive higher-order mindreading, and given that young children appear not to be such higher-order mindreaders yet? (Which, in fact, as much research suggests, they may actually become over development as a consequence rather than as a precursor of language acquisition.) This puzzle has been most clearly described by Richard Breheny in 2006 in the form of a trilemma (Breheny 2006): (i) Verbal communication requires higher-order intentionality (that is, a propositional attitude “Theory of Mind” – as it is often called in developmental psychology – that involves concepts of belief, etc.) (ii) Young children before age 4 do not yet have such a Theory of Mind; yet (iii) Young children clearly do engage in verbal communication.

Young children learn selectively from reliable rather than unreliable models. Yet the question of what cognitive processes this early selectivity builds on remains unanswered. One line of research suggests that rational trait reasoning might be the basis of young children's selective trust, while others suggest less sophisticated processes. In this article, we provide an overview of the development of selective trust and introduce a new theoretical framework to explain the seemingly divergent findings. Young children's selective trust can best be explained by assuming two kinds of underlying cognitive processes: one fast, implicit, and heuristic process that provides default judgments, and one systematic, slow, and effortful process that intervenes under specific circumstances. We discuss findings in light of this framework and propose testable predictions for research.

Young children learn selectively from reliable rather than unreliable models. Yet the question of what cognitive processes this early selectivity builds on remains unanswered. One line of research suggests that rational trait reasoning might be the basis of young children's selective trust, while others suggest less sophisticated processes. In this article, we provide an overview of the development of selective trust and introduce a new theoretical framework to explain the seemingly divergent findings. Young children's selective trust can best be explained by assuming two kinds of underlying cognitive processes: one fast, implicit, and heuristic process that provides default judgments, and one systematic, slow, and effortful process that intervenes under specific circumstances. We discuss findings in light of this framework and propose testable predictions for research.

Imitation is a powerful and ubiquitous social learning strategy, fundamental for the development of individual skills and cultural traditions. Recent research on the cognitive foundations and development of imitation, though, presents a surprising picture: Although even infants imitate in selective, efficient, and rational ways, children and adults engage in overimitation. Rather than imitating selectively and efficiently, they sometimes faithfully reproduce causally irrelevant actions as much as relevant ones. In this article, we suggest a new perspective on this phenomenon by integrating established findings on children's more general capacities for rational action parsing with newer findings on overimitation. We suggest that overimitation is a consequence of children's growing capacities to understand causal and social constraints in relation to goals and that it rests on the human capacity to represent observed actions simultaneously on different levels of goal hierarchies.

Recent research has amply documented that even preschoolers learn selectively from others, preferring, for example, reliable over unreliable and competent over incompetent models. It remains unclear, however, what the cognitive foundations of such selective learning are, in particular, whether it builds on rational inferences or on less sophisticated processes. The current study, therefore, was designed to test directly the possibility that children are in principle capable of selective learning based on rational inference, yet revert to simpler strategies such as global impression formation under certain circumstances. Preschoolers (N = 75) were shown pairs of models that either differed in their degree of competence within one domain (strong vs. weak or knowledgeable vs. ignorant) or were both highly competent, but in different domains (e.g., strong vs. knowledgeable model). In the test trials, children chose between the models for strength- or knowledge-related tasks. The results suggest that, in fact, children are capable of rational inference-based selective trust: when both models were highly competent, children preferred the model with the competence most predictive and relevant for a given task. However, when choosing between two models that differed in competence on one dimension, children reverted to halo-style wide generalizations and preferred the competent models for both relevant and irrelevant tasks. These findings suggest that the rational strategies for selective learning, that children master in principle, can get masked by various performance factors.

Cooperation is essential for human society, and children engage in cooperation from early on. It is unclear, however, how children select their partners for cooperation. We know that children choose selectively whom to learn from (e.g. preferring reliable over unreliable models) on a rational basis. The present study investigated whether children (and adults) also choose their cooperative partners selectively and what model characteristics they regard as important for cooperative partners and for informants about novel words. Three- and four-year-old children (N = 64) and adults (N = 14) saw contrasting pairs of models differing either in physical strength or in accuracy (in labeling known objects). Participants then performed different tasks (cooperative problem solving and word learning) requiring the choice of a partner or informant. Both children and adults chose their cooperative partners selectively. Moreover they showed the same pattern of selective model choice, regarding a wide range of model characteristics as important for cooperation (preferring both the strong and the accurate model for a strength-requiring cooperation tasks), but only prior knowledge as important for word learning (preferring the knowledgeable but not the strong model for word learning tasks). Young children's selective model choice thus reveals an early rational competence: They infer characteristics from past behavior and flexibly consider what characteristics are relevant for certain tasks.