Children and adults' intuitions of what people can believe.

Two preregistered studies tested how 5- to 6-year-olds, 7- to 8-year-olds, and adults judged the possibility of holding alternative beliefs (N = 240, 110 females, U.S. sample, mixed ethnicities, data collected from September 2020 through October 2021). In Study 1, children and adults thought people could not hold different beliefs when their initial beliefs were supported by evidence (but judged they could without this evidential constraint). In Study 2, children and adults thought people could not hold different beliefs when their initial beliefs were moral beliefs (but judged they could without this moral constraint). Young children viewed moral beliefs as more constrained than adults. These results suggest that young children already have sophisticated intuitions of the possibility of holding various beliefs and how certain beliefs are constrained.

From outcome to process: A developmental shift in judgments of good reasoning.

What does it mean to reason well? One might argue that good reasoning means that the outcome of the reasoning process is correct: reaching the right belief. Alternatively, good reasoning might refer to the reasoning process itself: following the right epistemic procedures. In a preregistered study, we investigated children's (4-9-year-olds) and adults' judgments of reasoning in China and the US (N = 256). Participants of all age groups evaluated the outcome when the process was kept constant - they favored agents who reached correct over incorrect beliefs, and they evaluated the process when the outcome was kept constant - they preferred agents who formed their beliefs using valid over invalid procedures. Developmental changes emerged when we pitted outcome against process: young children weighed outcome more heavily than process; older children and adults showed the reverse preference. This pattern was constant across the two cultural contexts, with the switch from outcome to process happening earlier in development in China. These results suggest that children initially value what someone believes, but, with development, come to increasingly value how beliefs are formed.

Do chimpanzees reason logically?

Psychologists disagree about the development of logical concepts such as or and not. While some theorists argue that infants reason logically, others maintain that logical inference is contingent on linguistic abilities and emerges around age 4. In this Registered Report, we conducted five experiments on logical reasoning in chimpanzees. Subjects (N = 16; 10 females; M = 24 years) participated in the same setup that has been administered to children: the two-, three-, and four-cup-task. Chimpanzees performed above chance in the two-cup-, but not in the three-cup-task. Furthermore, chimpanzees selected the logically correct option more often in the test than the control condition of the four-cup-task. We discuss possible interpretations of these findings and conclude that our results are most consistent with non-deductive accounts.

How children revise their beliefs in light of reasons.

We investigate how the ability to respond appropriately to reasons provided in discourse develops in young children. In Study 1 (N = 58, Germany, 26 girls), 4- and 5-, but not 3-year-old children, differentiated good from bad reasons. In Study 2 (N = 131, Germany, 64 girls), 4- and 5-year-old children considered both the strength of evidence for their initial belief and the quality of socially provided reasons for an alternative view when deciding whether to change their minds. Study 3 (N = 80, the United States, 42 girls, preregistered) shows that 4- and 5-year-old children also consider meta-reasons (reasons about reasons) in their belief revision. These results suggest that by age 4, children possess key critical thinking capacities for participating in public discourse.

Spreading the game: An experimental study on the link between children's overimitation and their adoption, transmission, and modification of conventional information.

Overimitation is hypothesized to foster the spread of conventional information within populations. The current study tested this claim by assigning 5-year-old children (N = 64) to one of two study populations based on their overimitation (overimitators [OIs] vs. non-overimitators [non-OIs]). Children were presented with conventional information in the form of novel games lacking instrumental outcomes, and we observed children's adoption, transmission, and modification of this information across two study phases. Results reveal little variation across study populations in the number of game elements that were adopted and transmitted. However, OIs were more likely to use normative language than non-OIs when transmitting game information to their peers. Furthermore, non-OIs modified the games more frequently in the initial study phase, suggesting an inverse relationship between children's overimitation and their tendency to modify conventional information. These findings indicate subtle yet coherent links between children's overimitation and their tendency to transmit and modify conventional information.

Evidence for a dual-process account of over-imitation: Children imitate anti- and prosocial models equally, but prefer prosocial models once they become aware of multiple solutions to a task.

Children imitate actions that are perceivably unnecessary to achieve the instrumental goal of an action sequence, a behavior termed over-imitation. It is debated whether this behavior is based on the motivation to follow behavioral norms and affiliate with the model or whether it can be interpreted in terms of a behavioral heuristic to copy observed intentional actions without questioning the purpose of each action step. To resolve this question, we tested whether preschool-aged children (N = 89) over-imitate a prosocial model, a helper in a prior third-party moral transgression, but refuse to over-imitate an antisocial model, the perpetrator of the moral transgression. After first observing an inefficient way to extract a reward from a puzzle box from either a perpetrator or a helper, children over-imitated the perpetrator to the same degree as they over-imitated the helper. In a second phase, children were then presented the efficient solution by the respective other model, i.e. the helper or the perpetrator. Over-imitation rates then dropped in both conditions, but remained significantly higher than in a baseline condition only when children had observed the prosocial model demonstrate the inefficient action sequence and the perpetrator performed the efficient solution. In contrast, over-imitation dropped to baseline level when the perpetrator had modelled the inefficient actions and the prosocial model subsequently showed children the efficient solution. In line with a dual-process account of over-imitation, results speak to a strong initial tendency to imitate perceivably irrelevant actions regardless of the model. Imitation behavior is then adjusted according to social motivations after deliberate consideration of different options to attain the goal.

Carry-over effects of tool functionality and previous unsuccessfulness increase overimitation in children.

Children 'overimitate' causally irrelevant actions in experiments where both irrelevant and relevant actions involve a single common tool. This study design may make it harder for children to recognize the irrelevant actions, as the perceived functionality of the tool during the demonstration of the relevant action may be carried over to the irrelevant action, potentially increasing overimitation. Moreover, little is known how overimitation is affected by the demonstrator's expressed emotions and the child's prior success with the task. Here, 131 nine- to ten-year-old French and German children first engaged in a tool-based task, being successful or unsuccessful, and then watched an adult demonstrating the solution involving one irrelevant and one relevant action before smiling or remaining neutral. These actions were performed with the same tool or with two separate tools, testing potential carry-over effects of the functionality of the relevant action on the irrelevant action. We show that overimitation was higher when the same tool was used for both actions and when children were previously unsuccessful, but was not affected by the demonstrator's displayed emotion. Our results suggest that future overimitation research should account for the number of tools used in a demonstration and participants' previous task experience.

Interpersonal Neural Synchrony During Father-Child Problem Solving: An fNIRS Hyperscanning Study.

Interpersonal neural synchrony (INS) has been previously evidenced in mother-child interactions, yet findings concerning father-child interaction are wanting. The current experiment examined whether fathers and their 5- to 6-year-old children (N = 66) synchronize their brain activity during a naturalistic interaction, and addressed paternal and child factors related to INS. Compared to individual problem solving and rest, father-child dyads showed increased INS in bilateral dorsolateral prefrontal cortex and left temporo-parietal junction during cooperative problem solving. Furthermore, the father's attitude toward his role as a parent was positively related to INS during the cooperation condition. These results highlight the implication of the father's attitude to parenting in INS processes for the first time.

Preschoolers' Motivation to Over-Imitate Humans and Robots.

From preschool age, humans tend to imitate causally irrelevant actions-they over-imitate. This study investigated whether children over-imitate even when they know a more efficient task solution and whether they imitate irrelevant actions equally from a human compared to a robot model. Five-to-six-year-olds (N = 107) watched either a robot or human retrieve a reward from a puzzle box. First a model demonstrated an inefficient (Trial 1), then an efficient (Trial 2), then again the inefficient strategy (Trial 3). Subsequent to each demonstration, children copied whichever strategy had been demonstrated regardless of whether the model was a human or a robot. Results indicate that over-imitation can be socially motivated, and that humanoid robots and humans are equally likely to elicit this behavior.

Neural synchrony in mother-child conversation: Exploring the role of conversation patterns.

Conversations are an essential form of communication in daily family life. Specific patterns of caregiver-child conversations have been linked to children's socio-cognitive development and child-relationship quality beyond the immediate family environment. Recently, interpersonal neural synchronization has been proposed as a neural mechanism supporting conversation. Here, we present a functional near-infrared spectroscopy (fNIRS) hyperscanning study looking at the temporal dynamics of neural synchrony during mother-child conversation. Preschoolers (20 boys and 20 girls, M age 5;07 years) and their mothers (M age 36.37 years) were tested simultaneously with fNIRS hyperscanning while engaging in a free verbal conversation lasting for 4 min. Neural synchrony (using wavelet transform coherence analysis) was assessed over time. Furthermore, each conversational turn was coded for conversation patterns comprising turn-taking, relevance, contingency and intrusiveness. Results from linear mixed-effects modeling revealed that turn-taking, but not relevance, contingency or intrusiveness predicted neural synchronization during the conversation over time. Results are discussed to point out possible variables affecting parent-child conversation quality and the potential functional role of interpersonal neural synchronization for parent-child conversation.

The effects of interaction quality on neural synchrony during mother-child problem solving.

Understanding others is fundamental to interpersonal coordination and successful cooperation. One mechanism posited to underlie both effective communication and behavioral coordination is interpersonal neural synchrony. Although presumably foundational for children's social development, research on neural synchrony in naturalistic caregiver-child interactions is lacking. Using dual-functional near-infrared spectroscopy (fNIRS), we examined the effects of interaction quality on neural synchrony during a problem-solving task in 42 dyads of mothers and their preschool children. In a cooperation condition, mothers and children were instructed to solve a tangram puzzle together. In an individual condition, mothers and children performed the same task alone with an opaque screen between them. Wavelet transform coherence (WTC) was used to assess the cross-correlation between the two fNIRS time series. Results revealed increased neural synchrony in bilateral prefrontal cortex and temporo-parietal areas during cooperative as compared to individual problem solving. Higher neural synchrony during cooperation correlated with higher behavioral reciprocity and neural synchrony predicted the dyad's problem-solving success beyond reciprocal behavior between mothers and children. State-like factors, such as maternal stress and child agency during the task, played a bigger role for neural synchronization than trait-like factors, such as child temperament. Our results emphasize neural synchrony as a biomarker for mother-child interaction quality. These findings further highlight the role of state-like factors in interpersonal synchronization processes linked to successful coordination with others and in the long-term might improve the understanding of others.

Contrasting Social and Cognitive Accounts on Overimitation: The Role of Causal Transparency and Prior Experiences.

Three experiments (N = 100) examine the influence of causal information on overimitation. In Experiment 1, a transparent reward location reveals that the reward is unaffected by nonfunctional actions. When 5-year-olds observe an inefficient and subsequently an efficient strategy to retrieve a reward, they show overimitation in both phases-even though the reward is visible. In Experiment 2, children observe first the efficient then the inefficient strategy. The latter is always demonstrated communicatively, whereas the efficient strategy is presented communicatively (2a) or noncommunicatively (2b). Regardless of whether the efficient strategy is emphasized through communication or not, most children do not switch from the efficient to the inefficient strategy. Depending on the situation, children base their behavior on social motivations or causal information.

The role of social interaction and pedagogical cues for eliciting and reducing overimitation in preschoolers.

The tendency to imitate causally irrelevant actions is termed overimitation. Here we investigated (a) whether communication of a model performing irrelevant actions is necessary to elicit overimitation in preschoolers and (b) whether communication of another model performing an efficient action modulates the subsequent reduction of overimitation. In the study, 5-year-olds imitated irrelevant actions both when they were modeled by a communicative and pedagogical experimenter and when they were modeled by a non-communicative and non-pedagogical experimenter. However, children stopped using the previously learned irrelevant actions only when they were subsequently shown the more efficient way to achieve the goal by a pedagogical experimenter. Thus, communication leads preschoolers to adapt their imitative behavior but does not seem to affect overimitation in the first place. Results are discussed with regard to the importance of communication for the transmission of cultural knowledge during development.