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Cheating is harmful to others and society at large. Promises have been shown to increase honesty in children, but their effectiveness has not been compared between different cultural contexts. In a study (2019) with 7‐ to 12‐year‐olds (N = 406, 48% female, middle‐class), voluntary promises reduced cheating in Indian, but not in German children. Children in both contexts cheated, but cheating rates were lower in Germany than in India. In both contexts, cheating decreased with age in the (no‐promise) control condition and was unaffected by age in the promise condition. These findings suggest that there may exist a threshold beyond which cheating cannot be further reduced by promises. This opens new research avenues on how children navigate honesty and promise norms. [ABSTRACT FROM AUTHOR]

There is extensive research on children's intergroup attitudes, but their perceptions of refugee children have rarely been studied. We conducted a study with 5- and 6-year-old children (N = 60) in Germany following the arrival of unprecedented large numbers of refugees in 2015 and 2016. Children completed a set of three tasks that measured their perceptions of refugee children (minority group) and German children (majority group): a draw-a-typical-child task (including questions about whether participants wanted to interact with the depicted child), an intergroup attitude task, and a liking task. Results indicate that participants drew similar pictures of and had similar intentions to interact with refugee children and German children. There was mixed evidence for group favouritism: while participants showed similar explicit attitudes towards German and refugee peers, they indicated more liking of German peers. Moreover, children viewed refugee children as a less variable (more homogeneous) group than German children. Opportunities for intergroup contact with refugee peers (i.e., whether participants attended kindergartens with or without refugee children) had no discernible effect on any of the measures. Our findings provide a snapshot of children's perceptions of refugees in a unique historical context and contribute to research on the development of intergroup attitudes in real-world settings. [ABSTRACT FROM AUTHOR]

Can Boyer's model of ownership psychology provide useful insights for comparative research? I apply his model to argue that we currently have evidence for possession psychology (based on competitive resource acquisition) in non-human primates, but not for ownership psychology. [ABSTRACT FROM AUTHOR]

Individuals in all societies conform to their cultural group's conventional norms, from how to dress on certain occasions to how to play certain games. It is an open question, however, whether individuals in all societies actively enforce the group's conventional norms when others break them. We investigated third-party enforcement of conventional norms in 5- to 8-y-old children (n = 376) from eight diverse small-scale and large-scale societies. Children learned the rules for playing a new sorting game and then, observed a peer who was apparently breaking them. Across societies, observer children intervened frequently to correct their misguided peer (i.e., more frequently than when the peer was following the rules). However, both the magnitude and the style of interventions varied across societies. Detailed analyses of children's interactions revealed societal differences in children's verbal protest styles as well as in their use of actions, gestures, and nonverbal expressions to intervene. Observers' interventions predicted whether their peer adopted the observer's sorting rule. Enforcement of conventional norms appears to be an early emerging human universal that comes to be expressed in culturally variable ways. [ABSTRACT FROM AUTHOR]

Human cooperation is probably supported by our tendency to punish selfishness in others. Social norms play an important role in motivating third-party punishment (TPP), and also in explaining societal differences in prosocial behaviour. However, there has been little work directly linking social norms to the development of TPP across societies. In this study, we explored the impact of normative information on the development of TPP in 603 children aged 4–14, across six diverse societies. Children began to perform TPP during middle childhood, and the developmental trajectories of this behaviour were similar across societies. We also found that social norms began to influence the likelihood of performing TPP during middle childhood in some of these societies. Norms specifying the punishment of selfishnesswere generally more influential than norms specifying the punishment of prosocial behaviour. These findings support the view that TPP of selfishness is important in all societies, and its development is shaped by a shared psychology for responding to normative information. Yet, the results also highlight the important role that children’s prior knowledge of local norms may play in explaining societal variation in the development of both TPP and prosociality. [ABSTRACT FROM AUTHOR]

Human cooperation is probably supported by our tendency to punish selfishness in others. Social norms play an important role in motivating third-party punishment (TPP), and also in explaining societal differences in prosocial behaviour. However, there has been little work directly linking social norms to the development of TPP across societies. In this study, we explored the impact of normative information on the development of TPP in 603 children aged 4–14, across six diverse societies. Children began to perform TPP during middle childhood, and the developmental trajectories of this behaviour were similar across societies. We also found that social norms began to influence the likelihood of performing TPP during middle childhood in some of these societies. Norms specifying the punishment of selfishness were generally more influential than norms specifying the punishment of prosocial behaviour. These findings support the view that TPP of selfishness is important in all societies, and its development is shaped by a shared psychology for responding to normative information. Yet, the results also highlight the important role that children's prior knowledge of local norms may play in explaining societal variation in the development of both TPP and prosociality. [ABSTRACT FROM AUTHOR]

Social learning strategies are key for making adaptive decisions, but their ontogeny remains poorly understood. We investigate how social information use depends on its source (adults vs. peer), and how it is shaped by household composition (extended vs. nuclear), a factor known to modulate social development. Using a simple estimation task, we show that social information strongly impacts the behaviour of adolescents aged 11 to 15 years (N = 256), especially when its source is an adult. However, social information use does not depend on household composition: the relative impact of adults and peers was similar in adolescents from both household types. Furthermore, adolescents were found to directly copy others' estimates surprisingly frequently. This study provides novel insights into adolescents' social information use and contributes to understanding the ontogeny of social learning strategies. [ABSTRACT FROM AUTHOR]

There has been extensive research into the development of selective trust in testimony, but little is known about the development of selective trust in promises. The present research investigates children's (N = 264) selective trust in others' promises to help. In Study 1, 6-year-olds selectively trusted speakers who had previously kept a promise. In Study 2, 5-year-olds displayed selective trust for speakers who had previously kept a prosocial promise (promise to help). In Study 3, 5-year-olds trusted a speaker, who kept a prosocial promise, over a helper. These data suggest that from the age of 5 children show selective trust in others' promises using prosociality, promise keeping, or both to inform their judgments. [ABSTRACT FROM AUTHOR]

Ownership is a cornerstone of many human societies and can be understood as a cooperative arrangement, where individuals refrain from taking each other's property. Owners can thus trust others to respect their property even in their absence. We investigated this principle in 5- to 7-year-olds (N = 152) from 4 diverse societies. Children participated in a resource task with a peer-partner, where we established ownership by assigning children to one side or the other of an apparatus and by marking resources with colors to help children keep track of them. When retrieving resources in the partner's presence, the majority of children took their own things and respected what belonged to their partner. A proportion of children in all societies also respected ownership in their partner's absence, although the strength of respect varied considerably across societies. We discuss implications for the development of ownership concepts and possible explanations for societal differences. [ABSTRACT FROM AUTHOR]

• We investigated whether ownership affects how 2–3-year-olds allocate resources. • Children generally selected fewer of another agent's resources when taking than when giving. • Children also took fewer of the agents resources than their own. • When giving to the agent, children selected the agent's resources more than resources not belonging to the agent. In three experiments, we investigated whether 2- and 3-year-olds (N = 240) consider ownership when taking resources for themselves and allocating resources to another agent. When selecting resources for themselves, children generally avoided taking resources that belonged to another agent and instead favored their own resources (Experiments 1 and 2). However, they did not avoid taking the agent's resources when the only other resources available were described as not belonging to the agent (Experiment 3). Children also selected fewer of the agent's resources when taking for themselves than when giving to the agent (Experiments 2 and 3). In giving to the agent, children were more likely to select the agent's resources than resources not belonging to the agent (Experiment 3). These findings show that ownership affects how 2- and 3-year-olds allocate resources. The findings also provide new evidence that 2-year-olds may respect others' ownership rights, at least to a limited degree, although we also consider an alternative explanation for the findings. [ABSTRACT FROM AUTHOR]

Sharing of resources is a common feature of human societies. Yet, there is substantial societal variation in children's generosity, and this variation emerges during middle childhood. Societal differences in self-construal orientation may be one factor influencing the ontogeny of generosity. Here, we examine anonymous Dictator Game sharing in 7-and-8-year-olds from two distinct societies: India and the UK (N = 180). We used self-construal manipulations to investigate whether priming self- or other-focused conversations would differentially influence children's generosity. There were no differences in generosity between populations. While a significant reduction in generosity was found following self-priming in both societies, other-priming was ineffectual. The findings are discussed in relation to experimental features and the role of anonymity and reputational concerns. [ABSTRACT FROM AUTHOR]

Refugee youth constitute around a third of the refugee population in Germany. We studied the experiences of newly arrived Syrian and Iraqi refugee youth, aged 14 to 18 years (N = 20), in Germany. We utilized semi-structured interviews and thematic analysis to investigate (a) the main challenges faced by youth and (b) their main coping resources to deal with these challenges. We grouped challenges into three levels: the individual level, the immediate social level, and the broader societal level. The most frequently mentioned challenges in our sample related to psychological wellbeing, school, friendship, accommodation, and discrimination. Youth reported relying on social support (friends, family, social services) and on themselves (through avoidance, persistence, activity seeking, active engagement) to cope with their challenges. Our findings provide insights into refugee youth's experiences in Germany, encompassing the acculturative, developmental, and generational aspects of their lives and demonstrating their coping and resilience. We discuss our results in relation to the literature on refugee youth in high-income countries. [ABSTRACT FROM AUTHOR]

Interactions with peers are fundamental to socio‐cognitive development, but assessing peer interactions in standardized experiments is challenging. Therefore, researchers commonly utilize puppetry to simulate peers. This Registered Report investigated urban German children's (AgeRange = 3.5–4.5 years; N = 144; 76♀) mind ascriptions and social cognition to test whether they treat puppets like peers, adults, or neither. Children attributed less mind properties to puppets than peers or adults. However, children's social cognition (i.e., normativity, prosociality, and theory of mind) varied little across partners. Puppetry relies on children's ability for pretense, but can provide valid insights into socio‐cognitive development. Implications for using puppets as stand‐ins for peers in developmental research are discussed. [ABSTRACT FROM AUTHOR]

Promises are speech acts that create an obligation to do the promised action. In three studies, we investigated whether 3- and 5-year-olds ( N = 278) understand the normative implications of promising in prosocial interactions. In Study 1, children helped a partner who promised to share stickers. When the partner failed to uphold the promise, 3- and 5-year-olds protested and referred to promise norms. In Study 2, when children in this same age range were asked to promise to continue a cleaning task—and they agreed—they persisted longer on the task and mentioned their obligation more frequently than without such a promise. They also persisted longer after a promise than after a cleaning reminder (Study 3). In prosocial interactions, thus, young children feel a normative obligation to keep their promises and expect others to keep their promises as well. [ABSTRACT FROM AUTHOR]

Western preschool children often assign ownership based on first possession and some theorists have proposed that this judgment might be an early emerging, innate bias. Five- to 9-year-olds (n = 112) from a small-scale group in Kenya (Kikuyu) watched videotaped interactions of two women passing an object. The object's starting position and the women's gestures were varied. Use of the first possession heuristic increased with age, and 8- to 9-year-olds performed similarly to German 5-year-olds (n = 24). Starting position and gestures had no effect. A control study confirmed that 5-year-old Kikuyus (n = 20) understood the video material. The findings reveal that the first possession heuristic follows different developmental trajectories cross-culturally and stress the role of children's sociocultural environment. [ABSTRACT FROM AUTHOR]

Creative labour has an effect on children's and adults' ownership decisions in Western cultures. We investigated whether preschoolers and adults from an Eastern culture ( Japan) would show a similar bias. In a first-party task (Experiment 1), in which participants created their own objects, Japanese preschoolers but not adults assigned ownership to creators. When participants watched videos of third-party conflicts between owners of materials and creators (Experiment 2), Japanese adults, but not preschoolers, transferred ownership to creators. In a British comparison group, both preschoolers and adults showed an effect of creative labour in the third-party task. A bias to attribute ownership on the basis of creative labour is thus not specific to Western culture. [ABSTRACT FROM AUTHOR]

People often assign ownership to the person who has invested labor into making an object (labor rule). However, labor usually improves objects and increases their value, and it has not been investigated whether these considerations underlie people's use of the labor rule. We presented participants with third-party ownership conflicts between an owner of materials and an artist who used the materials for some artwork. Experiment 1 revealed that participants were more likely to transfer ownership to the artist for low-value materials than for high-value materials, and Experiment 2 showed that this effect was further moderated by the amount of effort the artist had invested. A third experiment confirmed that participants transferred ownership more often if the artist's labor had increased the value of the materials than when it had added no value. These findings suggest that considerations for value underlie ownership transfers following the investment of labor. [ABSTRACT FROM AUTHOR]

Highlights: [•] We investigated children's understanding of ownership rights for new objects. [•] Children protested when their own objects were taken away and referred to ownership. [•] 3-year-olds attributed ownership to a third party, but failed to intervene on her behalf. [•] Ownership claims were due to effort invested as little ownership protest occurred for raw materials. [Copyright &y& Elsevier]

Merit is a key principle of fairness: rewards should be distributed according to how much someone contributed to a task. Previous research suggests that children have an early ability to take merit into account in third-party situations but that merit-based sharing in first-party contexts does not emerge until school-age. Here we provide evidence that three- and five-year-old children already use merit to share resources with others, even when sharing is costly for the child. In Study 1, a child and a puppet-partner collected coins that were later exchanged for rewards. We varied the work-contribution of both partners by manipulating how many coins each partner collected. Children kept fewer stickers in trials in which they had contributed less than in trials in which they had contributed more than the partner, showing that they took merit into account. Few children, however, gave away more than half of the stickers when the partner had worked more. Study 2 confirmed that children related their own work-contribution to their partner's, rather than simply focusing on their own contribution. Taken together, these studies show that merit-based sharing is apparent in young children; however it remains constrained by a self-serving bias. [ABSTRACT FROM AUTHOR]

The endowment effect describes the bias that people often value things that they possess more than things they do not possess. Thus, they are often reluctant to trade items in their possession for items of equivalent value. Some nonhuman primates appear to share this bias with humans, but it remains an open question whether they show endowment effects to the same extent as humans do. We investigated endowment effects in all four great ape species (Pan paniscus, Pan troglodytes, Gorilla gorilla, Pongo pygmaeus) by varying whether apes were endowed with food items (Experiment 1, N = 22) or tools that were instrumental in retrieving food (Experiment 2, N = 23). We first assessed apes' preferences for items of a pair and their willingness to trade items in their possession. We then endowed apes with one item of a pair and offered them to trade for the other item. Apes showed endowment effects for food, but not for tools. In Experiment 3, we endowed bonobos (N = 4) and orangutans (N = 5) with either one or 12 food items. Endowment effects did not differ between species and were not influenced by the number of endowed food items. Our findings suggest that endowment effects in great apes are restricted to immediate food gratification and remain unaffected by the quantity of food rewards. However, endowment effects do not seem to extend to other, nonconsumable possessions even when they are instrumental in retrieving food. In general, apes do not show endowment effects across a range of different commodities as humans typically do. [ABSTRACT FROM AUTHOR]

Social network analysis offers new tools to study the social structure of primate groups. We used social network analysis to investigate the cohesiveness of a grooming network in a captive chimpanzee group ( N = 17) and the role that individuals may play in it. Using data from a year-long observation, we constructed an unweighted social network of preferred grooming interactions by retaining only those dyads that groomed above the group mean. This choice of criterion was validated by the finding that the properties of the unweighted network correlated with the properties of a weighted network (i.e. a network representing the frequency of grooming interactions) constructed from the same data. To investigate group cohesion, we tested the resilience of the unweighted grooming network to the removal of central individuals (i.e. individuals with high betweenness centrality). The network fragmented more after the removal of individuals with high betweenness centrality than after the removal of random individuals. Central individuals played a pivotal role in maintaining the network's cohesiveness, and we suggest that this may be a typical property of affiliative networks like grooming networks. We found that the grooming network correlated with kinship and age, and that individuals with higher social status occupied more central positions in the network. Overall, the grooming network showed a heterogeneous structure, yet did not exhibit scale-free properties similar to many other primate networks. We discuss our results in light of recent findings on animal social networks and chimpanzee grooming. Am. J. Primatol. 73:758-767, 2011. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Recognizing property ownership is of critical importance in social interactions, but little is known about how and when this attribute emerges. We investigated whether preschool children and adults believe that ownership of one person’s property is transferred to a second person following the second person’s investment of creative labor in that property. In our study, an experimenter and a participant borrowed modeling-clay objects from each other to mold into new objects. Participants were more likely to transfer ownership to the second individual after he or she invested creative labor in the object than after any other manipulations (holding the object, making small changes to it). This effect was significantly stronger in preschool children than in adults. Duration of manipulation had no effect on property-ownership transfer. Changes in the object’s identity acted only as a secondary cue for children. We conclude that ownership is transferred after an investment of creative labor and that determining property ownership may be an intuitive process that emerges in early childhood. [ABSTRACT FROM PUBLISHER]

Animals commonly use feature and spatial strategies when remembering places of interest such as food sources or hiding places. We conducted three experiments with great apes to investigate strategy preferences and factors that may shape them. In the first experiment, we trained 17 apes to remember 12 different food locations on the floor of their sleeping room. The 12 food locations were associated with one feature cue, so that feature and spatial cues were confounded. In a single test session, we brought the cues into conflict and found that apes, irrespective of species, showed a preference for a feature strategy. In the second experiment, we used a similar procedure and trained 25 apes to remember one food location on a platform in front of them. On average, apes preferred to use a feature strategy but some individuals relied on a spatial strategy. In the final experiment, we investigated whether training might influence strategy preferences. We tested 21 apes in the platform set-up and found that apes used both, feature and spatial strategies irrespective of training. We conclude that apes can use feature and spatial strategies to remember the location of hidden food items, but that task demands (e.g. different numbers of search locations) can influence strategy preferences. We found no evidence, however, for the role of training in shaping these preferences. [ABSTRACT FROM AUTHOR]

In this study we show that bonobos and capuchin monkeys can learn to search in the middle of a landmark configuration in a small-scale space. Five bonobos (Pan paniscus) and 2 capuchin monkeys (Cebus apella) were tested in a series of experiments with the expansion test paradigm. The primates were trained to search in the middle of a 4- or 2-landmark configuration, and were then tested with the same configuration expanded. Neither species searched in the middle of the expanded 4-landmark configuration. When presented with a 2-landmark configuration and a constant or variable inter-landmark training distance, the subjects sometimes searched preferentially in the middle of the expanded configuration. We discuss 2 alternative explanations of the results: extracting a middle rule or averaging between different goal-landmark vectors. In any case, compared to adult humans, primates appear highly constrained in their abilities to search in the middle of a configuration of detached landmarks. We discuss some of the factors that may influence the primates' behavior in this task. [ABSTRACT FROM AUTHOR]

There are sometimes legitimate reasons for breaking a promise when circumstances change. We investigated 3- and 5-year-old German children's understanding of promise breaking in prosocial (helping someone else) and selfish (playing with someone else) conditions. In Study 1 (n = 80, 50% girls), preschoolers initially kept their own promise in all conditions. When they eventually broke their promise, 3-year-olds' justifications mostly referenced salient events, whereas 5-year-olds also referenced social norms. In Study 2 (n = 65, 49% girls), 5-year-olds preferred others' promise-breaking more in prosocial than selfish conditions; 3-year-olds showed the reverse pattern. Three-year-olds' justifications focused on desires, whereas 5-year-olds focused on relevant events. Overall, 3-year-olds were able to offer justifications, but 5-year-olds started to distinguish what counted in the eyes of others as "good" and "bad" reasons for promise breaking. • We studied children's understanding of promise-breaking in prosocial and selfish conditions. • 3- and 5-year-olds kept their own promises in all conditions. • 3- and 5-year-olds reasoned differently about others' promise-breaking. • 5-year-olds distinguish good and bad justifications for promise-breaking. [ABSTRACT FROM AUTHOR]

Creating objects can increase our evaluation of them, even when we compare them to physically identical copies (IKEA effect). Here we evaluate the influence of collaboration on the IKEA effect in two societies--the United Kingdom and India. One hundred twenty-eight 5-to-6-year-old children (48% female, 50% British middle class, 50% Indian middle class) assembled toys in pairs. Half of the children collaborated to assemble a single toy and half assembled their own toy. In both societies, children demonstrated an IKEA effect (ηp² = .19), valuing their own creation over an identical copy. This was the case regardless of whether children collaborated or worked independently. In summary, it seems that the IKEA effect is a potent bias that is present in diverse societies and is insensitive to others' contributions in a collaborative environment. [ABSTRACT FROM AUTHOR]

Access to and control of resources is a major source of costly conflicts. Animals, under some conditions, respect what others control and use (i.e. possession). Humans not only respect possession of resources, they also respect ownership. Ownership can be viewed as a cooperative arrangement, where individuals inhibit their tendency to take others' property on the condition that those others will do the same. We investigated to what degree great apes follow this principle, as compared to human children. We conducted two experiments, in which dyads of individuals could access the same food resources. The main test of respect for ownership was whether individuals would refrain from taking their partner's resources even when the partner could not immediately access and control them. Captive apes (N = 14 dyads) failed to respect their partner's claim on food resources and frequently monopolized the resources when given the opportunity. Human children (N = 14 dyads), tested with a similar apparatus and procedure, respected their partner's claim and made spontaneous verbal references to ownership. Such respect for the property of others highlights the uniquely cooperative nature of human ownership arrangements. [ABSTRACT FROM AUTHOR]

• Subtle self-construal priming has diverse effects sharing in different societies. • Selfishness increases following independence-priming in both India and the UK. • Only Indian children show greater generosity following interdependence-priming. • Differences in self-construals affects how easily children are moved to generosity. • The findings inform effects of sociocultural transformations around the world. Most humans share to some degree. Yet, from middle childhood, sharing behavior varies substantially across societies. Here, for the first time, we explored the effect of self-construal manipulation on sharing decisions in 7- and 8-year-old children from two distinct societies: urban India and urban United Kingdom. Children participated in one of three conditions that focused attention on independence, interdependence, or a control. Sharing was then assessed across three resource allocation games. A focus on independence resulted in reduced generosity in both societies. However, an intriguing societal difference emerged following a focus on interdependence, where only Indian children from traditional extended families displayed greater generosity in one of the resource allocation games. Thus, a focus on independence can move children from diverse societies toward selfishness with relative ease, but a focus on interdependence is very limited in its effectiveness to promote generosity. [ABSTRACT FROM AUTHOR]

We elevate our constructions to a special status in our minds. This 'IKEA' effect leads us to believe that our creations are more valuable than items that are identical, but constructed by another. This series of studies utilises a developmental perspective to explore why this bias exists. Study 1 elucidates the ontogeny of the IKEA effect, demonstrating an emerging bias at age 5, corresponding with key developmental milestones in self-concept formation. Study 2 assesses the role of effort, revealing that the IKEA effect is not moderated by the amount of effort invested in the task in 5-to-6-year olds. Finally, Study 3 examines whether feelings of ownership moderate the IKEA effect, finding that ownership alone cannot explain why children value their creations more. Altogether, results from this study series are incompatible with existing theories of the IKEA bias. Instead, we propose a new framework to examine biases in decision making. Perhaps the IKEA effect reflects a link between our creations and our self-concept, emerging at age 5, leading us to value them more positively than others' creations. [ABSTRACT FROM AUTHOR]

Researchers commonly use puppets in development science. Amongst other things, puppets are employed to reduce social hierarchies between child participants and adult experimenters akin to peer interactions. However, it remains controversial whether children treat puppets like real‐world social partners in these settings. This study investigated children's imitation of causally irrelevant actions (i.e., over‐imitation) performed by puppet, adult, or child models. Seventy‐two German children (AgeRange = 4.6–6.5 years; 36 girls) from urban, socioeconomically diverse backgrounds observed a model retrieving stickers from reward containers. The model performed causally irrelevant actions either in contact with the reward container or not. Children were more likely to over‐imitate adults' and peers' actions as compared to puppets' actions. Across models, they copied contact actions more than no‐contact actions. While children imitate causally irrelevant actions from puppet models to some extent, their social learning from puppets does not necessarily match their social learning from real‐world social agents, such as children or adults. Research Highlights: We examined children's over‐imitation from adult, child, and puppet models to validate puppetry as an approach to simulate non‐hierarchical interactions.Children imitated adults and child models at slightly higher rates than puppets.This effect was present regardless of whether the irrelevant actions involved physical contact to the reward container or not.In our study children's social learning from puppets does not match their social learning from human models. [ABSTRACT FROM AUTHOR]

When an object comes into possession, the owner will typically think that it is worth more than it did before they owned the item in a bias known as the endowment effect. This bias is particularly robust in Western societies with independent self-construals, but has not been observed in children below 5-6years of age. In three studies, we investigated whether endowment effect can be induced in younger children by focusing their attention on themselves. 120 children aged 3-4years evaluated toys before and after a task where they made pictures of themselves, a friend or a neutral farm scene. Over the three studies, children consistently evaluated their own possessions, relative to other identical toys, more positively following the self-priming manipulation. Together these studies support the notion that possessions can form part of an "extended self" from early on in development and that the endowment effect may be due to an attentional self-bias framing. [ABSTRACT FROM AUTHOR]

From early on, human infants acquire novel actions through observation and imitation. Yet, the neural mechanisms that underlie infants' action learning are not well understood. Here, we combine the assessment of infants' neural processes during the observation of novel actions on objects (i.e. transitive actions) and their subsequent imitation of those actions. Most importantly, we found that the 7–10 ​Hz motor cortex activity increased during action observation and predicted action imitation in 20-month-olds (n ​= ​36). 10-month-olds (n ​= ​42), who did not yet reliably imitate others' actions, showed a highly similar neural activity pattern during action observation. The presence or absence of communicative signals did neither affect infants' neural processing nor their subsequent imitation behavior. These findings provide first evidence for neural processes in the motor cortex that allow infants to acquire transitive actions from others ‒ and pinpoint a key learning mechanism in the developing brain of human infants. • We found increased 7–10 ​Hz motor cortex activity for the observation of novel actions in 10- and 20-month-olds. • 7–10 ​Hz motor cortex activity predicted subsequent action imitation in 20-month-olds. • Communicative signals did neither affect infants' neural processing nor their subsequent imitation behavior. • Neural processes in the motor cortex are of central importance for infants' acquisition of novel actions from others. [ABSTRACT FROM AUTHOR]