Mentalistic and normative frameworks in children's explanations of others' behaviors

As they learn to navigate the social world, children construct frameworks to interpret others' behavior. The present studies examined two such frameworks: a mentalistic framework, which construes behavior as driven by internal mental states; and a normative framework, which presumes people act in accordance with social norms. Participants included 101 children (ages 4, 7, and 10; 81% White; 41% female) and 35 adults (66% female) tested in the northeastern United States from 2019 to 2021. Children and adults utilized both mentalistic and normative frameworks to explain others' behaviors. Framework use depended on features of the behavior being explained. Minimal developmental differences were observed. The relative independence and the utility of the mentalistic and normative frameworks for naïve reasoning about behavior are considered.

The Origins of Theory of Mind in Infant Social Cognition: Investigating Longitudinal Pathways from Intention Understanding and Joint Attention to Preschool Theory of Mind

A growing body of literature has established longitudinal associations between key social cognitive capacities emerging in infancy and children's subsequent theory of mind. However, existing work is limited by modest sample sizes, narrow infant measures, and theory of mind assessments with restricted variability and generalizability. The current study aimed to extend this literature by (a) recruiting a large sample of participants (n = 116; 53 boys; 63 girls; all U.S. residents; 88 White, 8 Hispanic or Latino, 2 Black or African American, 14 two or more races/ethnicities, 4 unknown; median family income: $74-122,000), (b) examining multiple measures of infant social cognition (intentional action understanding, responding to joint attention, initiating joint attention) at Time 1 (8-12 months), and (c) using an ecologically valid theory of mind assessment designed to capture individual differences in preschoolers' mental state understanding (the Children's Social Understanding Scale; Tahiroglu et al., 2014) at Time 2 (37-45 months). Measured variable path analysis revealed a significant longitudinal association between infants' initiating joint attention and later theory of mind: infants who engaged in more attempts to initiate joint attention with experimenters through gaze alternation or gestures went on to show better parent-reported mental state understanding as preschoolers. Notably, the paths from infants' responding to joint attention and intentional action understanding to later theory of mind did not emerge as significant. These findings bolster and clarify existing claims about how mental state reasoning is rooted in foundational social-cognitive capacities emerging in infancy.

A longitudinal study of the differential social-cognitive foundations of early prosocial behaviors

A growing body of work has documented the emergence of instrumental helping and sharing in the second year of life; however, less is known about mechanisms that underlie development and production of prosocial behavior. The current study took a longitudinal approach to explore whether the origins of prosocial behaviors can be traced back to foundational social-cognitive capacities emerging in infancy. In a sample of 90 children, longitudinal relations were examined between intention understanding and joint attention measured in infancy (8-12 months) and later instrumental helping and sharing behavior assessed in the toddler years (18-25 months). We expected social-cognitive capacities supporting infants' understanding of others to be positively related to their prosocial behaviors as toddlers. Measured variable path analyses revealed two distinct developmental pathways from infant social cognition to later prosocial behavior: 1) Instrumental helping in the toddler years was positively predicted by intention understanding in infancy; 2) sharing in the toddler years was positively predicted by infants' initiating joint attention. These results lend support to proposals on the multidimensional nature of early prosocial behavior and offer the first longitudinal evidence that the origins of toddlers' prosocial behavior can be traced to social-cognitive capacities emerging in infancy.

Intentional action processing across the transition to crawling: Does the experience of self-locomotion impact infants' understanding of intentional actions?

Motor developmental milestones in infancy, such as the transition to self-locomotion, have cascading implications for infants' social and cognitive development. The current studies aimed to add to this literature by exploring whether and how crawling experience impacts a key social-cognitive milestone achieved in infancy: the development of intentional action understanding. Study 1 used a cross-sectional, age-held-constant design to examine whether locomotor (n = 36) and prelocomotor (n = 36) infants differ in their ability to process a failed intentional reaching action. Study 2 (n = 124) further probed this question by assessing how variability in locomotor infants' experience maps onto variability in their failed intentional action understanding. Both studies also assessed infants' tendency to engage in triadic interactions to shed light on whether self-locomotion impacts intentional action understanding directly or indirectly via changes in infants' interactions with social partners. Altogether, results showed no evidence for the role of self-locomotion in the development of intentional action understanding. Locomotor and prelocomotor infants did not differ in their failed action understanding or levels of triadic engagement (Study 1) and individual differences in days of crawling experience, propensity to crawl during play, and maximum crawling speed failed to predict infants' intentional action understanding or triadic engagement (Study 2). Explanations for these null findings and alternative influences on the development of intentional action understanding are considered.

Triadic interactions support infants' emerging understanding of intentional actions

Infants' understanding of the intentional nature of human action develops gradually across the first year of life. A key question is what mechanisms drive changes in this foundational social-cognitive ability. The current studies explored the hypothesis that triadic interactions in which infants coordinate attention between a social partner and an object of mutual interest promote infants' developing understanding of others as intentional agents. Infants' spontaneous tendency to participate in triadic engagement was assessed in a semi-structured play session with a researcher. Intentional action understanding was assessed by evaluating infants' ability to visually predict the goal of an intentional reaching action. Study 1 (N = 88) revealed that 8- to 9-month-olds who displayed more bouts of triadic engagement showed better concurrent reasoning about the goal of an intentional reaching action. Study 2 (N = 114) confirmed these findings using a longitudinal design and demonstrated that infants who displayed more bouts of triadic engagement at 6-7 months were better at prospectively reasoning about the goal of an intentional reaching action 3 months later. Cross-lagged path analyses revealed that intentional action understanding at 6-7 months did not predict later triadic engagement, suggesting that early triadic engagement supports later intentional action processing and not the other way around. Finally, evidence from both studies revealed the unique contribution of triadic over dyadic forms of engagement. These results highlight the importance of social interaction as a developmental mechanism and suggest that infants enrich their understanding of intentionality through triadic interactions with social partners.

Changes in Beliefs About Category Homogeneity and Variability Across Childhood

Effective category-based induction requires understanding that categories include both fundamental similarities between members and important variation. This article explores 4- to 11-year-olds' (n = 207) and adults' (n = 49) intuitions about this balance between within-category homogeneity and variability using a novel induction task in which participants predict the distribution of a property among members of a novel category. Across childhood, children learned to recognize variability within categories-showing increasing sensitivity to the role of property type and domain in constraining inferences. Children below the age of 6 showed evidence for a domain-general assumption that categories are homogeneous-generalizing properties broadly to 100% of category members. These studies support important developmental changes in category representations that may influence category-based induction.

Children's Developing Intuitions About the Truth Conditions and Implications of Novel Generics Versus Quantified Statements

Generic statements express generalizations about categories and present a unique semantic profile that is distinct from quantified statements. This paper reports two studies examining the development of children's intuitions about the semantics of generics and how they differ from statements quantified by all, most, and some. Results reveal that, like adults, preschoolers (a) recognize that generics have flexible truth conditions and are capable of representing a wide range of prevalence levels; and (b) interpret novel generics as having near-universal prevalence implications. Results further show that by age 4, children are beginning to differentiate the meaning of generics and quantified statements; however, even 7- to 11-year-olds are not adultlike in their intuitions about the meaning of most-quantified statements. Overall, these studies suggest that by preschool, children interpret generics in much the same way that adults do; however, mastery of the semantics of quantified statements follows a more protracted course.

Three-year-olds' theories of mind in actions and words

Understanding observable behavior by considering mental representations is central to social cognition. Research reveals quite different developmental trajectories for this ability depending on whether tasks assess implicit or explicit theory of mind (ToM). Yet, how to define implicit vs. explicit ToM, the tasks that elicit each, and the types of behavior that each can support, have remained unclear. The present study (n = 47) found that 3-year-olds incorporate predictions based on false beliefs into their intentional actions, but not - following identical scenarios - into their verbal responses. These data show that implicit ToM supports a broader range of behaviors than previously indicated and further illustrates the entrenched nature of the distinction between implicit and explicit knowledge in early conceptual development.

Infants' goal anticipation during failed and successful reaching actions

The ability to interpret and predict the actions of others is crucial to social interaction and to social, cognitive, and linguistic development. The current study provided a strong test of this predictive ability by assessing (1) whether infants are capable of prospectively processing actions that fail to achieve their intended outcome, and (2) how infants respond to events in which their initial predictions are not confirmed. Using eye tracking, 8-month-olds, 10-month-olds, and adults watched an actor repeatedly reach over a barrier to either successfully or unsuccessfully retrieve a ball. Ten-month-olds and adults produced anticipatory looks to the ball, even when the action was unsuccessful and the actor never achieved his goal. Moreover, they revised their initial predictions in response to accumulating evidence of the actor's failure. Eight-month-olds showed anticipatory looking only after seeing the actor successfully grasp and retrieve the ball. Results support a flexible, prospective social information processing ability that emerges during the first year of life.

Generic Language Use Reveals Domain Differences in Children's Expectations about Animal and Artifact Categories

The goal of the present study was to explore domain differences in young children's expectations about the structure of animal and artifact categories. We examined 5-year-olds' and adults' use of category-referring generic noun phrases (e.g., "Birds fly") about novel animals and artifacts. The same stimuli served as both animals and artifacts; thus, stimuli were perceptually identical across domains, and domain was indicated exclusively by language. Results revealed systematic domain differences: Children and adults produced more generic utterances when items were described as animals than artifacts. Because the stimuli were novel and lacking perceptual cues to domain, these findings must be attributed to higher-order expectations about animal and artifact categories. Overall, results indicate that by age 5, children are able to make knowledge-based domain distinctions between animals and artifacts that may be rooted in beliefs about the coherence and homogeneity of categories within these domains.

Do lions have manes? For children, generics are about kinds rather than quantities

Generic statements (e.g., "Lions have manes") make claims about kinds (e.g., lions as a category) and, for adults, are distinct from quantificational statements (e.g., "Most lions have manes"), which make claims about how many individuals have a given property. This article examined whether young children also understand that generics do not depend purely on quantitative information. Five-year-olds (n = 36) evaluated pairs of questions expressing properties that were matched in prevalence but varied in whether adults accept them as generically true (e.g., "Do lions have manes?" [true] vs. "Are lions boys?" [false]). Results demonstrated that children evaluate generics based on more than just quantitative information. Data suggest that even young children recognize that generics make claims about kinds.

Generic statements require little evidence for acceptance but have powerful implications

Generic statements (e.g., "Birds lay eggs") express generalizations about categories. In this paper, we hypothesized that there is a paradoxical asymmetry at the core of generic meaning, such that these sentences have extremely strong implications but require little evidence to be judged true. Four experiments confirmed the hypothesized asymmetry: Participants interpreted novel generics such as "Lorches have purple feathers" as referring to nearly all lorches, but they judged the same novel generics to be true given a wide range of prevalence levels (e.g., even when only 10% or 30% of lorches had purple feathers). A second hypothesis, also confirmed by the results, was that novel generic sentences about dangerous or distinctive properties would be more acceptable than generic sentences that were similar but did not have these connotations. In addition to clarifying important aspects of generics' meaning, these findings are applicable to a range of real-world processes such as stereotyping and political discourse.

Fast-mapping placeholders: Using words to talk about kinds

Fast-mapping is the ability to acquire a word rapidly on the basis of minimal information. As proposed by Carey (1978), we assume that children are able to achieve fast-mapping because their initial word meanings are skeletal placeholders that will be extended gradually over time. In this paper we propose that a notion of "kind" is fundamental to children's initial mappings for object labels. We illustrate this point by considering the acquisition of generic noun phrases, which are understood by children as kind-referring from very early on. We argue that the acquisition of generics has implications for mechanisms of word learning. Evidence suggests that generics cannot be acquired solely on the basis of associative learning mechanisms; rather, they are a default interpretation for young children.

Theory-based considerations influence the interpretation of generic sentences

Under what circumstances do people agree that a kind-referring generic sentence (e.g., "Swans are beautiful") is true? We hypothesized that theory-based considerations are sufficient, independently of prevalence/frequency information, to lead to acceptance of a generic statement. To provide evidence for this general point, we focused on demonstrating the impact of a specific theory-based, essentialist expectation-that the physical features characteristic of a biological kind emerge as a natural product of development-on participants' reasoning about generics. Across 3 studies, adult participants (N = 99) confirmed our hypothesis, preferring to map generic sentences (e.g., "Dontrets have long tails") onto novel categories for which the key feature (e.g., long tails) was absent in all the young but present in all the adults rather than onto novel categories for which the key feature was at least as prevalent but present in some of the young and in some of the adults. Control conditions using "some"- and "most"-quantified sentences demonstrated that this mapping is specific to generic meaning. These results suggest that generic meaning does not reduce to quantification and is sensitive to theory-based expectations.

Culture, Context, or Behavioral Control?

Joint book reading provides an ecological context for examining processes involved in the emergence of cultural differences in noun and verb use. Tardif, Gelman, & Xu (1999) found that English- and Mandarin-speaking mothers differed in their relative use of nouns and verbs during joint book reading with their 20-month-olds: Mandarin-speaking mothers produced more main verbs and fewer common nouns than did English-speaking mothers. We sought to clarify the source and specificity of these differences by reexamining these transcripts. Results indicated that cross-linguistic differences in noun and verb use do not arise from cross-cultural variation in behavioral control alone; differences persisted in picture-related conversations. Moreover, in both cultures, mothers' focus on objects and actions shifted in response to the nature of the pictures being discussed. Results are considered in terms of the relationship between culture-specific patterns of book reading, scene perception, and language acquisition.

Early intention understandings that are common to primates predict children's later theory of mind

Intention understanding emerges early in human development, manifest in deep and robust fashions even in infants. Overlapping intention understandings, encompassing agents as intentional actors and experiencers, are evident in nonhuman primates in more limited fashions. Intention understandings, of the sort shared by infants and nonhuman primates, predict the more comprehensive theory-of-mind understandings of older children. Those early understandings provide a platform for the ontogenesis of further, deeper achievements in the human case.

You can't always get what you want: infants understand failed goal-directed actions

At what age do infants understand that goals exist independently of the actions that result from them? Exploring infants' understanding of failed intentional actions-when the goal of the action is unfulfilled and thus not apparent in the actor's movements-is a critical step in answering this question. Using a visual habituation paradigm, we assessed when infants understand that a failed intentional action is goal directed and whether an understanding of successful intentional actions (actions that do overtly attain their goals) precedes an understanding of failed intentional actions. Results demonstrated that 10- and 12-month-olds recognized the goal directedness of both successful and failed reaching actions. Eight-month-olds also recognized the goal directedness of successful actions, but not of unsuccessful attempts. Thus, by the end of the 1st year of life, infants possess an impressive understanding of intentional action, and an understanding of failed intentional actions follows an earlier understanding of successful ones.

Differences in preschoolers' and adults' use of generics about novel animals and artifacts: a window onto a conceptual divide

Children and adults commonly produce more generic noun phrases (e.g., birds fly) about animals than artifacts. This may reflect differences in participants' generic knowledge about specific animals/artifacts (e.g., dogs/chairs), or it may reflect a more general distinction. To test this, the current experiments asked adults and preschoolers to generate properties about novel animals and artifacts (Experiment 1: real animals/artifacts; Experiments 2 and 3: matched pairs of maximally similar, novel animals/artifacts). Data demonstrate that even without prior knowledge about these items, the likelihood of producing a generic is significantly greater for animals than artifacts. These results leave open the question of whether this pattern is the product of experience and learned associations or instead a set of early-developing theories about animals and artifacts.

Feasibility of Computer-Administered Language Assessment

The assessment of language in early childhood is essential for the early identification of children with special needs. However, administering traditional language assessments to large preschool populations can be prohibitively time-consuming and complicated. Thus, there is clear value in developing a standardized, norm-referenced, computer-administered language assessment battery that is both time-efficient and fun for children, that yields a meaningful profile of children's specific language competencies, and that can be administered by testers in a consistent manner without extensive training. Here we discuss research undertaken as part of an evaluation of the feasibility of developing such a language assessment tool for use with preschool children. Preschoolers (M = 3.60 years) were tested using a traditional, standardized language assessment (PLS-4) and a computer-administered task assessing (via the use of a touch-screen computer) verb vocabulary and comprehension of plural morphology, negation, and noun-verb agreement. All participants completed the entire test without difficulty. Moreover, analyses revealed significant correlations between performance on the computer-based language assessment, age, and performance on the PLS-4. These data support the notion that a computer-administered language assessment is methodologically feasible and can provide a practical and valid means by which to assess early language abilities.

Action Speaks Louder Than Words: Young Children Differentially Weight Perceptual, Social, and Linguistic Cues to Learn Verbs

This paper explores how children use two possible solutions to the verb-mapping problem: attention to perceptually salient actions and attention to social and linguistic information (speaker cues). Twenty-two-month-olds attached a verb to one of two actions when perceptual cues (presence/absence of a result) coincided with speaker cues but not when these cues were placed into conflict (Experiment 1), and not when both possible referent actions were perceptually salient (Experiment 2). By 34 months, children were able to override perceptual cues to learn the name of an action that was not perceptually salient (Experiment 3). Results demonstrate an early reliance on perceptual information for verb mapping and an emerging tendency to weight speaker information more heavily over developmental time.