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.

To tell the truth or not: What effortful control, false belief, and sympathy tell us about preschoolers' instrumental lies.

This study aimed to examine the predictors of instrumental lies in preschool children, specifically focusing on false belief, effortful control, and sympathy. Instrumental lies are intentional falsehoods used to achieve personal goals such as avoiding punishment and obtaining an undeserved reward. A total of 192 preschool children (age range = 32-73 month-olds), along with their mothers and fathers, participated in the study. The Temptation Resistance Paradigm, an experimental task, was employed to elicit instrumental lies from the children. The children also completed first-order false belief measures, and their parents filled out questionnaires assessing their children's effortful control and sympathy skills. Results revealed a positive association between children's effortful control and their decisions to tell instrumental lies. However, no significant relationship was found between false belief and instrumental lying. Age moderated the link between sympathy and the decision to tell instrumental lies, with sympathy being negatively associated with lie-telling behavior among older children but showing no effect among younger children. The study variables did not predict the maintenance of instrumental lies. Overall, this study provides valuable insights into the role of effortful control and sympathy as underlying temperamental and emotional processes influencing children's decisions to engage in instrumental lie-telling.

Three- and 5-year-old children know their current belief might be wrong.

By 4 or 5 years of age, children understand when their own past beliefs were incorrect, or when others' current beliefs are incorrect. In the current study, we asked whether young children understand when their own current belief might be incorrect. 3- and 5-year old children (N = 77) made a judgment and then experienced a puppet making a judgment about the same situation. Children of both ages rechecked their evidence more often when the puppet disagreed with them than when it agreed with them (and the nature of their rechecking was different in the two conditions as well). These results suggest that already by 3 years of age children understand that they might currently be wrong, and they know that rechecking the evidence can resolve their uncertainty.

Investigating belief understanding in children in a nonverbal ambiguous displacement and communication setting.

Finding ways to investigate false belief understanding nonverbally is not just important for preverbal children but also is the only way to assess theory of mind (ToM)-like abilities in nonhuman animals. In this preregistered study, we adapted the design from a previous study on pet dogs to investigate false belief understanding in children and to compare it with belief understanding of those previously tested dogs. A total of 32 preschool children (aged 5-6 years) saw the displacement of a reward and obtained nonverbal cueing of the empty container from an adult communicator holding either a true or false belief. In the false belief condition, when the communicator did not know the location of the reward, children picked the baited container, but not the cued container, more often than the empty one. In the true belief condition, when the communicator witnessed the displacement yet still cued the wrong container, children performed randomly. The children's behavior pattern was at odds with that of the dogs tested in a previous study, which picked the cued container more often when the human communicator held a false belief. In addition to species comparisons, because our task does not require verbal responses or relational sentence understanding, it can also be used in preverbal children. The children in our study behaved in line with the existing ToM literature, whereas most (but not all) dogs from the previously collected sample, although sensitive to differences between the belief conditions, deviated from the children. This difference suggests that using closely matched paradigms and experimental procedures can reveal decisive differences in belief processing between species. It also demonstrates the need for a more comprehensive exploration and direct comparison of the various aspects of false belief processing and ToM in different species to understand the evolution of social cognition.

Unringing the bell: Successful debriefing following a rich false memory study.

In rich false memory studies, familial informants often provide information to support researchers in planting vivid memories of events that never occurred. The goal of the current study was to assess how effectively we can retract these false memories via debriefing - i.e., to what extent can we put participants back the way we found them? We aimed to establish (1) what proportion of participants would retain a false memory or false belief following debriefing, and (2) whether richer, more detailed memories would be more difficult to retract. Participants (N = 123) completed a false memory implantation protocol as part of a replication of the "Lost in the Mall" study (Loftus & Pickrell, Psychiatric Annals, 25, 720-725, 1995). By the end of the protocol, 14% of participants self-reported a memory for the fabricated event, and a further 52% believed it had happened. Participants were then fully debriefed, and memory and belief for the false event were assessed again. In a follow-up assessment 3 days post-debriefing, the false memory rate had dropped to 6% and false belief rates also fell precipitously to 7%. Moreover, virtually all persistent false memories were found to be nonbelieved memories, where participants no longer accepted that the fabricated event had occurred. Richer, more detailed memories were more resistant to correction, but were still mostly retracted. This study provides evidence that participants can be "dehoaxed", and even very convincing false memories can be retracted.

The role of social cognition in mental health trajectories from childhood to adolescence.

We investigated the association between an aspect of Theory of Mind in childhood, false-belief understanding, and trajectories of internalising (emotional and peer) and externalising (conduct and hyperactivity) problems in childhood and adolescence. The sample was 8408 children from the UK's Millennium Cohort Study, followed at ages 5, 7, 11, 14, and 17 years. Social cognitive abilities were measured at 5 and 7 years through a vignette version of the Sally-Anne task administered by an unfamiliar assessor in a socially demanding dyadic interaction. Internalising and externalising problems were measured via the Strengths and Difficulties Questionnaire at 7-17 years. Using latent growth modelling, and after controlling for sex, ethnicity, maternal education, verbal ability, and time-varying family income, we found that superior social cognitive abilities predicted a decrease in emotional problems over time. In sex-stratified analyses, they predicted decreasing conduct problem trajectories in females and lower levels of conduct problems at baseline in males.

An initial but receding altercentric bias in preverbal infants' memory.

Young learners would seem to face a daunting challenge in selecting to what they should attend, a problem that may have been exacerbated in human infants by changes in carrying practices during human evolution. A novel theory proposes that human infant cognition has an altercentric bias whereby early in life, infants prioritize encoding events that are the targets of others' attention. We tested for this bias by asking whether, when the infant and an observing agent have a conflicting perspective on an object's location, the co-witnessed location is better remembered. We found that 8- but not 12-month-olds expected the object to be at the location where the agent had seen it. These findings suggest that in the first year of life, infants may prioritize the encoding of events to which others attend, even though it may sometimes result in memory errors. However, the disappearance of this bias by 12 months suggests that altercentricism is a feature of very early cognition. We propose that it facilitates learning at a unique stage in the life history when motoric immaturity limits infants' interaction with the environment; at this stage, observing others could maximally leverage the information selection process.

Canine perspective-taking.

An important question in the study of canine cognition is how dogs understand humans, given that they show impressive abilities for interacting and communicating with us. In this review, we describe and discuss studies that have investigated dogs' perspective-taking abilities. There is solid evidence that dogs are not only sensitive to the gaze of others, but also their attention. We specifically address the question whether dogs have the ability to take the perspective of others and thus come to understand what others can or cannot perceive. From the latter, they may then infer what others know and use this representation to anticipate what others do next. Still, dogs might simply rely on directly observable cues and on what they themselves can perceive when they assess what others can perceive. And instead of making inferences from representations of others' mental states, they may have just learned that certain behaviours of ours lead to certain outcomes. However, recent research seems to challenge this low-level explanation. Dogs have solved several perspective-taking tasks instantly and reliably across a large number of variations, including geometrical gaze-following, stealing in the dark, concealing information from others, and Guesser/Knower differentiation. In the latter studies, dogs' choices between two human informants were strongly influenced by cues related to the humans' visual access to the food, even when the two informants behaved identically. And finally, we review a recent study that found dogs reacting differently to misleading suggestions of human informants that have either a true or false belief about the location of food. We discuss this surprising result in terms of the comprehension of reality-incongruent mental states, which is considered as a hallmark of Theory of Mind acquisition in human development. Especially on the basis of the latter findings, we conclude that pet dogs might be sensitive to what others see, know, intend, and believe. Therefore, this ability seems to have evolved not just in the corvid and primate lineages, but also in dogs.

Toddlers' social evaluations of agents who act on false beliefs.

Mature social evaluations privilege agents' intentions over the outcomes of their actions, but young children often privilege outcomes over intentions in verbal tasks probing their social evaluations. In three experiments (N = 118), we probed the development of intention-based social evaluation and mental state reasoning using nonverbal methods with 15-month-old toddlers. Toddlers viewed scenarios depicting a protagonist who sought to obtain one of two toys, each inside a different box, as two other agents observed. Then, the boxes' contents were switched in the absence of the protagonist and either in the presence or the absence of the other agents. When the protagonist returned, one agent opened the box containing the protagonist's desired toy (a positive outcome), and the other opened the other box (a neutral outcome). When both agents had observed the toys move to their current locations, the toddlers preferred the agent who opened the box containing the desired toy. In contrast, when the agents had not seen the toys move and therefore should have expected the desired toy's location to be unchanged, the toddlers preferred the agent who opened the box that no longer contained the desired toy. Thus, the toddlers preferred the agent who intended to make the protagonist's desired toy accessible, even when its action, guided by a false belief concerning that toy's location, did not produce a positive outcome. Well before children connect beliefs to social behavior in verbal tasks, toddlers engage in intention-based evaluations of social agents with false beliefs.

Two systems for thinking about others' thoughts in the developing brain.

Human social interaction crucially relies on the ability to infer what other people think. Referred to as Theory of Mind (ToM), this ability has long been argued to emerge around 4 y of age when children start passing traditional verbal ToM tasks. This developmental dogma has recently been questioned by nonverbal ToM tasks passed by infants younger than 2 y of age. How do young children solve these tests, and what is their relation to the later-developing verbal ToM reasoning? Are there two different systems for nonverbal and verbal ToM, and when is the developmental onset of mature adult ToM? To address these questions, we related markers of cortical brain structure (i.e., cortical thickness and surface area) of 3- and 4-y-old children to their performance in novel nonverbal and traditional verbal TM tasks. We showed that verbal ToM reasoning was supported by cortical surface area and thickness of the precuneus and temporoparietal junction, classically involved in ToM in adults. Nonverbal ToM reasoning, in contrast, was supported by the cortical structure of a distinct and independent neural network including the supramarginal gyrus also involved in emotional and visual perspective taking, action observation, and social attention or encoding biases. This neural dissociation suggests two systems for reasoning about others' minds-mature verbal ToM that emerges around 4 y of age, whereas nonverbal ToM tasks rely on different earlier-developing possibly social-cognitive processes.

The posterior cerebellum and temporoparietal junction support explicit learning of social belief sequences.

This study tests the hypothesis that the posterior cerebellum is involved in social cognition by identifying and automatizing sequences of social actions. We applied a belief serial reaction time task (Belief SRT task), which requires mentalizing about two protagonists' beliefs about how many flowers they receive. The protagonists' beliefs could either be true or false depending on their orientation (true belief: oriented towards and directly observing the flowers; or false belief: oriented away and knowing only prior information about flowers). A Control SRT task was created by replacing protagonists and their beliefs with shapes and colors. Participants were explicitly told that there was a standard sequence related to the two protagonists' belief orientations (Belief SRT task) or the shapes' colors (Control SRT task). Both tasks included a Training phase where the standard sequence was repeated and a Test phase where this standard sequence was interrupted by random sequences. As hypothesized, compared with the Control SRT task, the Belief SRT task recruited the posterior cerebellar Crus II and the temporoparietal junction (TPJ) more. Faster response times were correlated with less Crus II activation and with more TPJ activation, suggesting that the Crus II supported automatizing the belief sequence while the TPJ supported inferring the protagonists' beliefs. Also as hypothesized, compared with an implicit version of the Belief SRT task (i.e., participants did not know about the existence of sequences; Ma, Pu, et al., 2021b), the cerebellar Crus I &II was engaged less during initial training and automatic application of the sequence, and the cortical TPJ was activated more in processing random sequences.

Evidence for goal- and mixed evidence for false belief-based action prediction in 2- to 4-year-old children: A large-scale longitudinal anticipatory looking replication study.

Unsuccessful replication attempts of paradigms assessing children's implicit tracking of false beliefs have instigated the debate on whether or not children have an implicit understanding of false beliefs before the age of four. A novel multi-trial anticipatory looking false belief paradigm yielded evidence of implicit false belief reasoning in 3- to 4-year-old children using a combined score of two false belief conditions (Grosse Wiesmann, C., Friederici, A. D., Singer, T., & Steinbeis, N. [2017]. Developmental Science, 20(5), e12445). The present study is a large-scale replication attempt of this paradigm. The task was administered three times to the same sample of N = 185 children at 2, 3, and 4 years of age. Using the original stimuli, we did not replicate the original finding of above-chance belief-congruent looking in a combined score of two false belief conditions in either of the three age groups. Interestingly, the overall pattern of results was comparable to the original study. Post-hoc analyses revealed, however, that children performed above chance in one false belief condition (FB1) and below chance in the other false belief condition (FB2), thus yielding mixed evidence of children's false belief-based action predictions. Similar to the original study, participants' performance did not change with age and was not related to children's general language skills. This study demonstrates the importance of large-scaled replications and adds to the growing number of research questioning the validity and reliability of anticipatory looking false belief paradigms as a robust measure of children's implicit tracking of beliefs.

The influence of group membership on false-belief attribution in preschool children.

The ability to infer beliefs and thoughts in interaction partners is essential in social life. However, reasoning about other people's beliefs might depend on their characteristics or our relationship with them. Recent studies indicated that children's false-belief attribution was influenced by a protagonist's age and competence. In the current experiments, we investigated whether group membership influences the way children reason about another person's beliefs. We hypothesized that 4-year-olds would be less likely to attribute false beliefs to an ingroup member than to an outgroup member. Group membership was manipulated by accent (Experiments 1-3) and gender (Experiment 4). The results indicated that group membership did not consistently influence children's false-belief attribution. Future research should clarify whether the influence of group membership on false-belief attribution either is absent or depends on other cues that we did not systematically manipulate in our study.

The roles of behavioral and affective cues and false belief in children's trait attributions.

Children as young as 3 years can make trait attributions based on behavioral and emotional cues, but such skills continue to develop across childhood. ​Theory of mind understanding, the ability to attribute mental states to oneself and others, may provide a foundation for early development of trait attributions. The purpose of the current study was to explore the impact of behavioral and affective cues on children's trait attributions, if their attributes changed incrementally across five repeated instances of an observed behavior, and to what extent such patterns of attributions are related to false belief, a key concept of theory of mind. A total of 115 3- to 5-year-olds completed theory of mind tasks and two trait attribution tasks with affect and the nature of behavior (helpful/unhelpful) varied. Use of a quantitative histogram enabled identification of subtle changes in attributions across episodes. Results indicated that preschool-aged children rated characters as less likable with repeated instances of unhelpful behavior, with meaningful changes occurring after a second case of behavior. The 5-year-olds were more sensitive to differences in helpfulness than the other two age groups. In addition, the 4-year-olds rated smiling helpful characters more positively across time, suggesting a potential impact of emotional cues. Moreover, false belief was related to, yet did not account for, children's attributions. Factors affecting young children's formation of trait attributions are discussed.

Disagreement, justification, and equitable moral judgments: A brief training study.

Although theorists agree that social interactions play a major role in moral development, previous research has not experimentally assessed how specific features of social interactions affect children's moral judgments and reasoning. The current study assessed two features: disagreement and justification. In a brief training phase, children aged 4-5.5 years (N = 129) discussed simple moral scenarios about issues of fairness (how to allocate things between individuals) with a puppet who, in a between-participants factorial design, either agreed or disagreed with the children's ideas and either asked or did not ask the children to justify their ideas. Children then responded to another set of moral scenarios in a test phase that was the same for all children. Children in the "agree and do not justify" baseline condition showed an inflexible equality bias (preferring only equal allocations regardless of context), but children who had experiences of disagreement or experiences of being asked to justify themselves shifted toward making equitable decisions based on common ground norms and values. Furthermore, false belief competence was related to children's decisions and justifications. These findings support the classic Piagetian hypothesis that social interactions are a catalyst of cognitive disequilibrium and moral development.

The posterior cerebellum supports implicit learning of social belief sequences.

Recent studies have documented the involvement of the posterior cerebellar Crus (I & II) in social mentalizing, when sequences play a critical role. We investigated for the first time implicit learning of belief sequences. We created a novel task in which true and false beliefs of other persons were alternated in an adapted serial reaction time (SRT) paradigm (Belief SRT task). Participants observed two protagonists whose beliefs concerning reality were manipulated, depending on their orientation toward the scene (true belief: directly observing the situation) or away from it (false belief: knowing only the prior situation). Unbeknownst to the participants, a fixed sequence related to the two protagonists' belief orientations was repeated throughout the task (Training phase); and to test the acquisition of this fixed sequence, it was occasionally interrupted by random sequences (Test phase). As a nonsocial control, the two protagonists and their orientations were replaced by two different shapes of different colors respectively (Control SRT task). As predicted, the posterior cerebellar Crus I & II were activated during the Belief SRT task and not in the Control SRT task. The Belief SRT task revealed that Crus I was activated during the initial learning of the fixed sequence (Training phase) and when this learned sequence was interrupted by random sequences (Test phase). Moreover, Crus II was activated during occasional reappearance of the learned sequence in the context of sequence violations (Test phase). Our results demonstrate the contribution of the posterior cerebellar Crus during implicit learning and predicting new belief sequences.

Dogs follow human misleading suggestions more often when the informant has a false belief.

We investigated whether dogs (Canis familiaris) distinguish between human true (TB) and false beliefs (FB). In three experiments with a pre-registered change of location task, dogs (n = 260) could retrieve food from one of two opaque buckets after witnessing a misleading suggestion by a human informant (the 'communicator') who held either a TB or a FB about the location of food. Dogs in both the TB and FB group witnessed the initial hiding of food, its subsequent displacement by a second experimenter, and finally, the misleading suggestion to the empty bucket by the communicator. On average, dogs chose the suggested container significantly more often in the FB group than in the TB group and hence were sensitive to the experimental manipulation. Terriers were the only group of breeds that behaved like human infants and apes tested in previous studies with a similar paradigm, by following the communicator's suggestion more often in the TB than in the FB group. We discuss the results in terms of processing of goals and beliefs. Overall, we provide evidence that pet dogs distinguish between TB and FB scenarios, suggesting that the mechanisms underlying sensitivity to others' beliefs have not evolved uniquely in the primate lineage.

No links between genetic variation and developing theory of mind: A preregistered replication attempt of candidate gene studies.

Genetic variability is being discussed as a source of inter-individual differences in Theory of Mind development. Previous studies documented an association between variations in DRD4 VNTR 48 bp, OXTR rs53576, COMT rs4680, and Theory of Mind task performance. As empirical evidence on these associations is sparse, we conducted a preregistered replication attempt of a study reporting a link between DRD4 VNTR 48 bp and false belief understanding in 50-month-old children [Lackner, C., Sabbagh, M. A., Hallinan, E., Liu, X., & Holden, J. J. (2012). Developmental Science, 15(2), 272-280.]. Additionally, we attempted a replication of studies on the role of OXTR rs53576 and COMT rs4680 in Theory of Mind. In both replication attempts, we did not find any evidence for associations between the sampled genetic markers and Theory of Mind ability in a series of analyses. Extending the replication attempt of Lackner et al., we employed longitudinal data from several tasks and measurement points, which allowed us to run follow-up robustness checks with more reliable scores. These extensive analyses corroborated our null finding. This comprehensive non-replication is important to balance current research on genetic markers of Theory of Mind. In a combined evaluation of our own and previous studies, we point to substantial methodological issues that research on the genetic basis of Theory of Mind development faces. We conclude that these limitations currently prevent firm conclusions on genetic influences on Theory of Mind development.

Designer receptor inhibition suggests mechanism for monkey Theory of Mind.

Theory of Mind (ToM) is a critical component of human social cognition that has not been found reliably in other primates, especially monkeys. Hayashi et al. (Cell Reports, 30, 4433-4444, 2020) used newly developed behavioral techniques to detect evidence for ToM in Japanese macaque monkeys and employed sophisticated neurobiological manipulations to implicate the medial prefrontal cortex is this capacity.

Three-year-olds' spontaneous lying in a novel interaction-based paradigm and its relations to explicit skills and motivational factors.

Previous research has investigated children's lying and its motivational and social-cognitive correlates mostly through explicit tasks. The current study used an anticipatory interaction-based paradigm adopted from research with preverbal infants. We investigated 3-year-olds' spontaneous lying within interaction and its motivational basis and relations to explicit skills of lying, false belief understanding, inhibitory control, and socialization. Children interacted with puppets to secure stickers that were hidden in one of two boxes. Either a friend or a competitor puppet tried to obtain the stickers. Nearly all children helpfully provided information about the sticker's location to the friend, and about half of the sample anticipatorily provided false information to the competitor. Children misinformed the competitor significantly more often than the friend, both when the reward was for themselves and when it was for someone else. Explicitly planning to lie in response to a question occurred significantly less often but predicted spontaneous lying, as did passing the explicit standard false belief task. Thus, by 3 years of age, children spontaneously invoke false beliefs in others. This communicative skill reveals an interactional use of false belief understanding in that it requires holding one's perspective to pursue one's goal while providing a different perspective to distract a competitor. Findings support the view that practical theory of mind skills emerge for social coordination and serve as a basis for developing explicit false belief reasoning.