Abstract

As material resources are limited, partiality is sometimes unavoidable. Thus, even young children have to decide how to distribute their resources. At the same time, they experience that others’ prosocial behavior is also selective – affecting their expectations about others’ behavior. In this thesis I focus on children’s selective sharing behavior and selective sharing expectations in friendships. We know from previous research that children start to share selectively with their friends between 3 and 5 years (Birch & Billman, 1986; Buhrmester, Goldfarb, & Cantrell, 1992; Garon, Johnson, & Steeves, 2011; Moore, 2009; Paulus, 2016; Paulus & Moore, 2014; Yu, Zhu, & Leslie, 2016). Around the same time children also start to expect others to share more with their friends than with disliked peers or strangers (Afshordi, 2019; Liberman & Shaw, 2017; Olson & Spelke, 2008; Paulus, 2014a). However, why and how young children first start to show partial sharing behavior is still not fully resolved. The current thesis explores the underlying mechanisms and motives for young children’s preferential sharing with friends compared to their sharing with disliked peers or strangers. In addition, the thesis investigates whether preschoolers also expect their own friends to (preferentially) share with them and whether these expectations relate to children’s social behavior and their decision to rely on others. The current thesis compares and partially tests three – not necessarily exclusive – models, which could explain children’s selective sharing with friends. That is, affective processes, strategic motives, or a norm to share with friends could explain children’s partiality. Social- interactionist and constructivist theories (Carpendale, 2010; Carpendale, Hammond, & Atwood, 2013; Paulus, in press-a) suggest that affection and shared experiences could be responsible for children’s selective sharing behavior (Model 1). However, from an evolutionary or cognitive standpoint (Axelrod, 1984/2006; Kuhlmeier, Dunfield, & O'Neill, 2014; Trivers, 1971) it would be rational to share more with friends because the chance to get something in return is higher than with other peers (Model 2, strategic motives). This strategic explanation would also be in line with classical theories on friendship (Damon, 1977; Laursen & Hartup, 2002; Selman, 1980; Youniss & Volpe, 1978), which imply that preschoolers’ friendships are still mostly self-serving. And lastly, Model 3 proposes that preschoolers might share more with their friends out of a sense of interpersonal obligation (Furman & Bierman, 1983; Keller, Edelstein, Schmid, Fang, & Fang, 1998; Paulus, Christner, & Wörle, 2020). Study 1 and 2 examined the mechanisms underlying children’s selective sharing with friends. Study 1 shows that children’s selective sharing with friends is not subserved by strategic motives. Additionally, the results of Study 1 stress the role of the past relationship with a friend, making an affective explanation more likely. More importantly, the children in Study 2 justified their preferential sharing with friends mostly with positive affect, lending additional support to Model 1 (affective processes). Study 2 also provides some support for the idea that a feeling of obligation might add to the effect of affective processes on young children’s selective sharing. Thus, the results of the current thesis support the importance of affective processes and shared experiences for children’s selective sharing with friends (Model 1) and speak against strategic considerations as motivating factors. Study 3 investigated children’s sharing expectations in a first person scenario. The results show that children’s selective reliance on their friends’ sharing develops in the preschool period. Four- to 5-year-old but not 3-year-old children rely more on their friends than on their non-friends to share with them. Young children’s increasing reliance on their friends’ sharing demonstrates children’s developing understanding how relationships influence the intentions and behavior of others. This is an important ability because it allows children to choose cooperative interaction partners, maximize their gain and avoid exploitation (Afshordi & Liberman, 2021). In Study 3 older preschoolers were also willing to risk getting no resources by relying on their friend, thus indicating that children’s expectations manifest in their behavior. In sum, during the preschool years, children’s friendships seem to become affectionate, trusting, and reciprocal relationships in which both friends expect and provide prosocial support. Thus, young children’s friendships might be less superficial and self-serving than previously implied by classical studies.