Continuity in false belief understanding from 33 to 52 months of age

Conceptual continuity in children's false belief understanding from toddlerhood to childhood was investigated in a longitudinal study of 75 children. Performance in a low-demands false belief task at 33 months of age was significantly correlated with performance in a content false belief task at 52 months independent of language ability and executive function. In contrast, there was no correlation with performance in a location false belief task, which differed from the "Sally-Anne" format of the low-demands task and was high in executive demands. These findings support the view that explicit false belief understanding may be continuous from toddlerhood to childhood and that developmental change may be characterized in terms of enrichment and increasing stability of core conceptual understanding rather than in terms of fundamental change.

Contrasting one's share of the shared life space: Comparing the roles of metacognition and inhibitory control in the development of theory of mind among Scottish and Japanese children

Cultural comparisons suggest that an understanding of other minds may develop sooner in independent versus interdependent settings, and vice versa for inhibitory control. From a western lens, this pattern might be considered paradoxical, since there is a robust positive relationship between theory of mind (ToM) and inhibitory control in western samples. In independent cultures, an emphasis on one's own mind offers a clear route to 'simulate' other minds, and inhibitory control may be required to set aside one's own perspective to represent the perspective of others. However, in interdependent cultures, social norms are considered the key catalyst for behaviour, and metacognitive reflection and/or suppression of one's own perspective may not be necessary. The cross-cultural generalizability of the western developmental route to ToM is therefore questionable. The current study used an age-matched cross-sectional sample to contrast 56 Japanese and 56 Scottish 3-6-year-old's metacognition, ToM and inhibitory control skills. We replicated the expected cultural patterns for ToM (Scotland > Japan) and inhibitory control (Japan > Scotland). Supporting western developmental enrichment theories, we find that inhibitory control and metacognition predict theory of mind competence in Scotland. However, these variables cannot be used to predict Japanese ToM. This confirms that individualistic mechanisms do not capture the developmental mechanism underlying ToM in Japan, highlighting a bias in our understanding of ToM development. RESEARCH HIGHLIGHTS: We replicate an independent cultural advantage for theory of mind (Scotland > Japan) and interdependent advantage for inhibitory control (Japan > Scotland). From a western lens, this pattern might be considered paradoxical, since there is a robust positive relationship between theory of mind and inhibitory control. Supporting western developmental enrichment theories, we find that the development of inhibitory control mediates the link between metacognition and theory of mind in Scotland. However, this model does not predict Japanese theory of mind, highlighting an individualistic bias in our mechanistic understanding of theory of mind development.

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.

The origins of cognitive flexibility in chimpanzees

Cognitive flexibility is a core component of executive function, a suite of cognitive capacities that enables individuals to update their behavior in dynamic environments. Human executive functions are proposed to be enhanced compared to other species, but this inference is based primarily on neuroanatomical studies. To address this, we examined the nature and origins of cognitive flexibility in chimpanzees, our closest living relatives. Across three studies, we examined different components of cognitive flexibility using reversal learning tasks where individuals first learned one contingency and then had to shift responses when contingencies flipped. In Study 1, we tested n = 82 chimpanzees ranging from juvenility to adulthood on a spatial reversal task, to characterize the development of basic shifting skills. In Study 2, we tested how n = 24 chimpanzees use spatial versus arbitrary perceptual information to shift, a proposed difference between human and nonhuman cognition. In Study 3, we tested n = 40 chimpanzees on a probabilistic reversal task. We found an extended developmental trajectory for basic shifting and shifting in response to probabilistic feedback-chimpanzees did not reach mature performance until late in ontogeny. Additionally, females were faster to shift than males were. We also found that chimpanzees were much more successful when using spatial versus perceptual cues, and highly perseverative when faced with probabilistic versus consistent outcomes. These results identify both core features of chimpanzee cognitive flexibility that are shared with humans, as well as constraints on chimpanzee cognitive flexibility that may represent evolutionary changes in human cognitive development.

"I know what's inside because you showed me": Training 33-month-old children to attribute knowledge and ignorance to themselves and others

The present study investigated the role of language in two-year-old children's early understanding of knowledge and ignorance. An intense microgenetic training consisting of 12 to 14 training sessions within six to seven weeks was conducted between 33 and 36 months. One training group experienced and participated in discourse about epistemic states in theoretically relevant situations which highlighted, for instance, the relation between seeing and knowing or contrasts between different people's knowledge states. The other training group was trained on complement syntax using sentence repetition tasks. An age-matched control group received no training. The complement syntax training was not effective in improving complement syntax competence more than in the other two groups. In contrast, the mental state training led to higher improvements in the mental state training group than in the other two groups on tasks assessing comprehension of the targeted concepts (e.g., comprehension of the seeing-knowing relation). The mental state training also had an effect on children's metacognitive awareness of their own ignorance which was, however, not independent of complement syntax competence assessed at 33 months. No effect was obtained on epistemic perspective-taking skills. Our findings indicate that the use of mental state language in discourse promotes children's acquisition of epistemic concepts even before their third birthday.

Understanding Human Cognitive Uniqueness

Humanity has regarded itself as intellectually superior to other species for millennia, yet human cognitive uniqueness remains poorly understood. Here, we evaluate candidate traits plausibly underlying our distinctive cognition (including mental time travel, tool use, problem solving, social cognition, and communication) as well as domain generality, and we consider how human cognitive uniqueness may have evolved. We conclude that there are no traits present in humans and absent in other animals that in isolation explain our species' superior cognitive performance; rather, there are many cognitive domains in which humans possess unusually potent capabilities compared to those found in other species. Humans are flexible cognitive all-rounders, whose proficiency arises through interactions and reinforcement between cognitive domains at multiple scales.

Testing the stability of theory of mind: A longitudinal approach

An explicit understanding of false belief develops around the age of four years. However, tasks based on spontaneous responses have revealed an implicit understanding of belief and other theory of mind constructs in infants in their second year of life. The few longitudinal studies that have examined conceptual continuity of theory of mind from infancy to early childhood have reported mixed findings. Here we report two longitudinal experiments to investigate the developmental relation between implicit and explicit theory of mind. No link was observed in the first experiment between false belief and intention understanding measured at 14 and 18 months with the violation of expectation paradigm and tasks measuring explicit and implicit false belief at four or five years of age. In the second experiment, infants aged 18 months were tested with a battery of tasks that measured knowledge inference and false belief. They were then tested with the theory of mind scale at five years of age. The parents completed the Children's Social Understanding Scale (CSUS) and the Social Communication Questionnaire (SCQ). As in the first experiment, there were no associations between early and later forms of theory of mind. We suggest that these findings do not support the view that there is conceptual continuity in theory of mind development.

Theory of Mind and diverse intelligences in 4-year-olds: Modelling associations of false beliefs with children's numerate-spatial, verbal, and social intelligence

Theory of Mind (ToM) and the structure of intelligence were investigated in 115 4-year-olds. Specifically, we asked whether children's intelligence involves both general and specific aspects and whether standard ToM measures of false belief can serve as indicators of social intelligence. Psychometric intelligence and children's domain-specific understanding of number concepts and of mental states (false belief) were measured in the laboratory; communication and social skills were assessed through mothers' report. A confirmatory factor analysis revealed poor fit for a one-factor model, but good fit for a model with three correlated factors, suggesting that children's intelligence involves both general and specific aspects. Numerate-spatial and verbal intelligence were correlated (.70), and social intelligence correlated to a stronger degree with verbal (.66) than with numerate-spatial intelligence (.37). Laboratory assessment of false belief and mothers' reports about children's social skills loaded on a single factor, pointing to real-world consequences of ToM abilities. Statement of contribution What is already known on this subject? The structure of intelligence in 4-year-olds comprises domain-general and domain-specific dimensions. Some domain-specific dimensions are numerate-spatial, verbal, and social intelligence. What does this study add? Theory of Mind emerges as an aspect of children's social intelligence. Social intelligence (including Theory of Mind) is related to children's numerate-spatial abilities.

Theory of mind development: State of the science and future directions

This chapter offers a brief overview of how research on theory of mind development has developed over the recent years, with a focus on current research and theoretical accounts of theory of mind during the infancy period. The topics covered include the factors contributing to individual differences in theory of mind skills in preschoolers, the current replication crisis in theory of mind in infancy, the stability of theory of mind from infancy to childhood, and recent research suggesting that infants' concept of false belief is, at best, immature (e.g., overattribution to inanimate agents). Future directions in theory of mind research are suggested.