Young children can revise beliefs in light of new evidence, yet some philosophers argue that this is not true rationality. They define rationality as the capacity to reflect on and re-evaluate one's reasons for beliefs, tying it to language and proposing that it emerges only around the so-called "age of reason" (age 6). In challenge to this, we tested whether children aged 3 to 6 (N = 93) were capable of a basic form of reflective responsiveness to reasons: acquiring and responding to an undermining defeater-evidence that challenges the grounds for a belief-through exposure to overriding defeaters. In each trial, before choosing where to search, children observed a Reliable informant (100% accurate) and an Unreliable informant (50% accurate, 50% misleading) indicating one of two reward locations. Each misleading trial served as an overriding defeater, directly contradicting children's initial belief about the reward location. Age and language predicted children's tendency to follow the Reliable over the Unreliable informant suggesting they may have acquired an undermining defeater related to informant reliability. However, neither age nor language predicted preferences when the informants were pitted against each other in a new context. These findings suggest some basic capacity for reflective responsiveness to reasons may emerge earlier than the "age of reason", more independently of language than some philosophical accounts have assumed, and may be grounded in capacities (overriding defeaters) already present at the unreflective level.

Counterfactual reasoning -- the ability to consider what could, would, or should have happened alongside what actually occurred -- is foundational to causal understanding, learning from experience, and making sense of others’ minds. While this skill emerges in early childhood, its developmental trajectory remains debated. How does this ability develop and what other constructs is it related to? To investigate, we explored the development of counterfactual reasoning through a 14-item unmoderated online battery measuring counterfactual reasoning across narrative, physical, and causal-machine domains in 320 children (ages 3-7). We found steady improvement on the tasks, with performance improving over early to middle childhood. Performance was also positively correlated within all three tasks, controlling for age and performance on non-counterfactual cognitive tasks, suggesting that all three domains were tapping into a similar underlying counterfactual ability. Additionally, children who responded correctly on narrative counterfactuals that could not be solved using heuristic shortcuts performed better across the other counterfactual tasks (Study 1) and Theory of Mind tasks (Study 2). These findings provide evidence for a latent construct underlying counterfactual reasoning and introduce a validated tool for future research.

Rafetseder et al. (2021) were the first to demonstrate that children have difficulty revising their beliefs when objects morphed from one object (e.g. a rabbit) into another (e.g. a duck). Children aged four to eight reported the second object significantly later than adults. This is surprising, because both children and adults were presented with the same initial information (“it is a rabbit”) and were exposed to the same contradictory visual evidence. We conducted three experiments to replicate the results and to and explore reasons for children’s delayed belief revision. In Experiment 1 (N = 58; 3- to 6-year-olds), we demonstrated that children only struggle to identify the second object in the gradual condition, while displaying adult-like categorical perception when the same images were presented individually outside of the morphing context. In Experiment 2 (N = 86; 6- to 11-year-olds), we found that only children aged 9 years and over showed a similar pattern to adults, and that a global processing style facilitated identification of the second object. In Experiment 3 (N = 47, 5- to 6-year-olds), when children were explicitly informed of the two possible interpretations of the morphed images, their performance improved, although not to the level observed in the individual condition of Experiment 1. These findings suggest that children of different ages struggle to revise their beliefs in a gradually changing environment for different reasons. While older children may use less efficient, potentially local, exploration strategies, younger children may have difficulties with mental imagery.

Rafetseder et al. (2021) were the first to demonstrate that children have difficulty revising their beliefs when objects morphed from one object (e.g. a rabbit) into another (e.g. a duck). Children aged four to eight reported the second object significantly later than adults. This is surprising, because both children and adults held the same prior belief (“it is a rabbit”) and were exposed to the same contradictory evidence. We conducted three experiments to examine children’s delayed belief revision. In Experiment 1 (N = 58; 3–6-year-olds), we demonstrated that children only struggle to identify the second object in the gradual condition, while displaying adult-like categorical perception when the same images were presented individually outside of the morphing context. In Experiment 2 (N = 86; aged 6–11), we found that only children aged nine years and over showed a similar pattern to adults, and that a global processing style facilitated identification of the second object. In Experiment 3 (N = 47, 5–6-year-olds), when children were explicitly informed of the two possible interpretations of the morphed images, their performance increased, although not to the level observed in the individual condition of Experiment 1. These findings suggest that children of different ages struggle with the morphing task for different reasons. While older children may use less efficient, potentially local, exploration strategies, younger children may not explore at all due to their overconfidence in their initial priors.

Although exploratory play is considered a hallmark of cognitive development and learning, relatively few studies have been able to quantitatively characterize the shifts that may occur in children's approach to exploration. One reason for this gap is due to challenges coding and analyzing children's exploratory play behavior. In our paper, we employ a novel computational modeling approach to understand whether and how children's exploratory play patterns shift in early childhood (3- to 11-years-old). We analyze data from children (N = 432) across five different experiments that varied in the type of exploration task (including novel toys, novel topics, and novel envelopes). Children's behaviors were coded action-by-action according to whether children repeated an action on the same type of target, switched to a novel target, or terminated play. Our computational Markov model searches over the space of possible "stay," "switch," and "end" parameters to quantify child-specific transition probabilities. We find that overall, older children are less likely to perseverate, more likely to switch, and more likely to end the task earlier. Our approach provides a demonstration of how Markov models can be used to map the process of play, providing insight into theories of developmental changes in exploration. SUMMARY: We use Markov models to quantify developmental shifts in children's exploratory play across five naturalistic tasks. Older children showed increased exploratory variability and decreased perseveration during play. Developmental effects were most consistent in novel toy tasks, but varied across contexts. Our findings help reconcile conflicting prior research by highlighting the role of task structure and developmental changes in exploratory strategy.

Adults can reflectively revise their beliefs and selectively respond to unreliable informants, despite often forming and revising beliefs unreflectively without assessing their reasons. This study investigates how the strength of counterevidence coming from an informant affects adults' ability to infer that the informant is unreliable through acquiring and responding to undermining defeaters (i.e., evidence suggesting that something was wrong with how the belief was formed). Participants (N = 120) watched videos of two informants acting on two locations: one whose actions reliably indicated the reward location, and one whose actions did not. The strength of feedback participants received after making a choice was manipulated across two conditions. In the Strong feedback condition, participants received positive feedback when they found the reward and explicit negative feedback when they did not, along with information about the reward's true location. In the Weak feedback condition, they received positive feedback, but incorrect choices simply resulted in no reward. Participants responded selectively to unreliability, following the Unreliable informant's evidence less often than that of the Reliable informant. This effect was stronger in the Strong feedback condition and was observed after only two to three misleading trials. In subsequent trials where informants were pitted against each other, participants in the Strong feedback condition, but not in the Weak feedback condition, consistently preferred the Reliable informant. These findings suggest that adults' ability to infer informants' reliability depends on the strength of counterevidence. Additionally, exploratory analyses reveal a key distinction between acquiring and responding to undermining defeaters.

Some philosophers argue that reflection is key to rational thinking. By tying reflective thinking to language, they struggle to account for minimally verbal infants and exclude nonhuman animals. This study assessed processing of undermining defeaters-a basic form of reflective thinking-in 36 two-year-old British children (13 female; Mage = 30.4 months, 98% White), 39 dogs (18 female), and 21 pigs (9 female), tested between 2022 and 2023. Informants acted on two screens: one informant reliably indicated a rewarded location; the other informant did not. Informants switched actions twice, prompting subjects to infer their reliability. Willingness to follow informants' indications did not differ between reliable and unreliable informants. However, reduced following in later trials suggests a response to uncertainty or an undermining defeater.

Home enrichment plays an important role in shaping children's development. In the current study, we inquired whether home enrichment was associated with pre‐schoolers' visual working memory (VWM) function, a critical cognitive system necessary for maintaining information for short periods of time. Home enrichment was assessed using an adapted version of the Home Observation Measurement of the Environment Interview. VWM behavior and brain function were collected as children engaged with a color change detection task. Home enrichment was associated with right‐lateralized fronto‐parietal engagement. Specifically, greater home enrichment was linked to increased activation in the right angular gyrus, important for working memory maintenance, and suppression in the right inferior frontal gyrus (rIFG), important for re‐orienting attention to distracting events. Critically, home enrichment‐related rIFG suppression was linked to better VWM performance. This work sheds light on potential mechanism(s) through which enrichment in homes might be involved with cognitive function during the preschool years.

Neurocognition and academic abilities during the period of 4 and 7 years of age are impacted by both the transition from kindergarten to primary school and age-related developmental processes. Here, we used a school cut-off design to tease apart the impact of formal schooling from age, on working memory (WM) function, vocabulary, and numeracy scores. We compared two groups of children with similar age, across two years: first-graders (FG), who were enrolled into primary school the year that they became eligible and kindergarteners (KG), who were deferred school entry until the following year. All children completed a change detection task while brain activation was recorded using portable functional near-infrared spectroscopy, a vocabulary assessment, and a numeracy screener. Our results revealed that FG children showed greater improvement in WM performance and greater engagement of a left-lateralized fronto-parietal network compared to KG children. Further, they also showed higher gains in vocabulary and non-symbolic numeracy scores. This improvement in vocabulary and non-symbolic numeracy scores following a year in primary school was predicted by WM function. Our findings contribute to a growing body of literature examining neurocognitive and academic benefits conferred to children following exposure to formal schooling.

The first part of this chapter focuses on the development of our theory of mind or folk psychology. The second part gives a brief overview of how counterfactual reasoning develops and how this development interacts with theory of mind development. In both parts our focus is on developmental research that speaks to basic issues: What is the nature of our folk psychology, its genetic or experiential basis, its kinship with executive control and pragmatics, and its cognitive mechanism? Is there an ‘implicit’ theory that even infants master? How does counterfactual reasoning differ from conditional reasoning and why should counterfactual reasoning be important for folk psychology? We examine what answers forty years of research have produced so far.

The ability to take mental states such as goals into account when interpreting others' behavior has been proposed to be what sets human use of social information apart from that of other animals. If so, children's social information use would be expected to change as their understanding of others' mental states develops. We explored age-related changes in 3-to 7-year-old children's ability to strategically use social information by taking into account another's goal when it was, or was not, aligned with their own. Children observed as a puppet demonstrator selected a capsule, peeked inside, and chose to accept or reject it, following which children made their own selection. Children were able to account for others' conflicting motivations from around 4 years of age and reliably inferred the outcome of others' behavior from 6 years. However, using social information based on such inferences appeared to be challenging regardless of whether the demonstrator's goal was, or was not. aligned to that of the participant. We found that social information use improved with age; however, this improvement was restricted to cases in which the appropriate response was to avoid copying the demonstrator's selection. In contrast to previous research, appropriate copying responses remained at chance. Possible explanations for this unexpected pattern of results are discussed. The cognitive challenge associated with the ability to account for others' goals could offer humans a significant advantage over that of other animals in their ability to use social information.(c) 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/).

To differentiate the use of simple associations from use of explicitly reasoned selective social learning, we can look for age-related changes in children's behaviour that might signify a switch from one social learning strategy to the other. We presented 4- to 8-year-old children visiting a zoo in Scotland (N = 109) with a task in which the perceptual access of two informants was determined by the differing opacity of two screens of similar visual appearance during a hiding event. Initially success could be achieved by forming an association or inferring a rule based on salient visual (but causally irrelevant) cues. However, following a switch in the scenario, success required explicit reasoning about informants' potential to provide valuable information based on their perceptual access. Following the switch, older children were more likely to select a knowledgeable informant. This suggests that some younger children who succeeded in the pre-switch trials had inferred rules or formed associations based on superficial, yet salient, visual cues, whereas older children made the link between perceptual access and the potential to inform. This late development and apparent cognitive challenge are consistent with proposals that such capacities are linked to the distinctiveness of human cumulative culture.

Visual working memory (VWM) is reliably predictive of fluid intelligence and academic achievements. The objective of the current study was to investigate the nature of individual differences in pre-schoolers by examining the relationship between behaviour-brain function underlying VWM processing and parent-reported measures. We used a portable 8 x 8 channel functional near-infrared spectroscopy system to record from the frontal and parietal cortices of 4.5-year-old pre-school children (N=74) as they completed a colour change detection VWM task in their homes. Parents were asked to fill in questionnaires on temperament, academic aspirations, home environment, and life stress. Children were median-split into a low-performing (LP) and a high-performing (HP) group based on the number of items they could successfully remember during the task. LPs increasingly activated the bilateral frontal and parietal cortices with increasing load, whereas HPs showed no difference in activation across the loads. Our findings suggested that LPs recruited more neural resources when their VWM capacity was challenged. We employed mediation analyses to examine the association between the difference in activation between the highest and lowest loads, and variables from the questionnaires. The difference in activation in the right parietal cortex partially mediated the association between parent-reported stressful life events and VWM performance. Specifically, a higher number of stressful events was associated with lower VWM performance. Critically, our findings show that the association between VWM capacity, right parietal activation, and indicators of life stress is important to understand the nature of individual differences in VWM in pre-school children.

Children show marked improvements in executive functioning (EF) between 4 and 7 years of age. In many societies, this time period coincides with the start of formal school education, in which children are required to follow rules in a structured environment, drawing heavily on EF processes such as inhibitory control. This study aimed to investigate the longitudinal development of two aspects of inhibitory control, namely response inhibition and response monitoring and their neural correlates. Specifically, we examined how their longitudinal development may differ by schooling experience, and their potential significance in predicting academic outcomes. Longitudinal data was collected in two groups of children at their homes. At T1, all children were roughly 4.5 years of age and neither group had attended formal schooling. One year later at T2, one group (P1, n = 40) had completed one full year of schooling while the other group (KG, n = 40) had stayed in kindergarten. Behavioural and brain activation data (measured with functional near-infrared spectroscopy, fNIRS) in response to a Go/No-Go task and measures of academic achievement were collected. We found that P1 children, compared to KG children, showed a greater change over time in activation related to response monitoring in the bilateral frontal cortex. The change in left frontal activation difference showed a small positive association with mathematical ability, suggesting certain functional relevance of response monitoring for academic performance. Overall, the school environment is important in shaping the development of the neural network underlying monitoring of one own’s performance. Research Highlights Using a school cut-off design, we collected longitudinal home assessments of two aspects of inhibitory control, namely response inhibition and response monitoring, and their neural correlates. For response monitoring, P1 children showed a greater difference over time in activation between correct and incorrect responses in the bilateral frontal cortex. The left frontal activation difference in P1 children showed a small association with mathematical ability, suggesting some functional relevance of response monitoring for academic performance. The school environment plays an important role in shaping the development of the neural network underlying monitoring of one own’s performance.

Human cumulative culture has been suggested to depend on human-unique cognitive mechanisms, explaining its apparent absence in other species. We show that the potential for exhibiting cumulative culture depends on the cognitive abilities of the agents and the demands associated with using information generated by others' activity. 154 children aged 3-6 years played a searching game ("Find the Treasure"), taking their turn after a puppet demonstrator. The puppet's attempt revealed information about the contents of the locations searched, which could be exploited to target rewarded locations, and avoid unrewarded ones. Two conditions were presented, intended to capture realistic variation in the transience of the cues generated by another individual's activity. In one condition, the puppet's demonstration provided transient information - boxes were opened, seen to be rewarded or not, and then closed. In the other condition the puppet's chosen boxes remained partially open, providing an enduring visible cue as to whether that location was rewarded. Children undertook three trials of varying demonstration success, and we used patterns of performance to infer the potential for improvement over multiple generations of transmission. In the Enduring Cues condition, children's performance demonstrated the potential for cumulative culture. In contrast, in the Transient Information condition, only older children showed improved performances following higher success demonstrations and overall performance was not compatible with the possibility of improvements over generations of social transmission. We conclude that under certain conditions cumula-tive culture could occur in many species, but in a broader range of contexts in humans. (c) 2020 Elsevier Inc. All rights reserved.

Human learners are rarely the passive recipients of valuable social information. Rather, learners usually have to actively seek out information from a variety of potential others to determine who is in a position to provide useful information. Yet, the majority of developmental social learning paradigms do not address participants’ ability to seek out information for themselves. To investigate age-related changes in children’s ability to seek out appropriate social information, 3- to 8-year-olds (N = 218) were presented with a task requiring them to identify which of four possible demonstrators could provide critical information for unlocking a box. Appropriate information seeking improved significantly with age. The particularly high performance of 7- and 8-year-olds was consistent with the expectation that older children’s increased metacognitive understanding would allow them to identify appropriate information sources. Appropriate social information seeking may have been overlooked as a significant cognitive challenge involved in fully benefiting from others’ knowledge, potentially influencing understanding of the phylogenetic distribution of cumulative culture.

Increasing evidence suggests that counterfactual reasoning is involved in false belief reasoning. Because existing work is correlational, we developed a manipulation that revealed a signature of counterfactual reasoning in participants’ answers to false belief questions. In two experiments, we tested 3- to 14-year-olds and found high positive correlations (r = .56 and r = .73) between counterfactual and false belief questions. Children were very likely to respond to both questions with the same answer, also committing the same type of error. We discuss different theories and their ability to account for each aspect of our findings and conclude that reasoning about others’ beliefs and actions requires similar cognitive processes as using counterfactual suppositions. Our findings question the explanatory power of the traditional frameworks, theory theory and simulation theory, in favor of views that explicitly provide for a relationship between false belief reasoning and counterfactual reasoning.

Children until the age of five are only able to reverse an ambiguous figure when they are informed about the second interpretation. In two experiments, we examined whether children’s difficulties would extend to a continuous version of the ambiguous figures task. Children (Experiment 1: 66 3- to 5-year olds; Experiment 2: 54 4- to 9-year olds) and adult controls saw line drawings of animals gradually morph—through well-known ambiguous figures—into other animals. Results show a relatively late developing ability to recognize the target animal, with difficulties extending beyond preschool-age. This delay can neither be explained with improvements in theory of mind, inhibitory control, nor individual differences in eye movements. Even the best achieving children only started to approach adult level performance at the age of 9, suggesting a fundamentally different processing style in children and adults.