Melanie Killen

Melanie Killen
University of Maryland, College Park | UMD, UMCP, University of Maryland College Park · Department of Human Development and Quantitative Methodology

Ph.D.
Professor of Human Development and Quantitative Methodology at the University of Maryland.

About

226
Publications
89,200
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Introduction
I am a developmental psychologist working in the areas of moral reasoning, developmental intergroup attitudes, social exclusion, prejudice, theory of mind and morality, soical cognitive development, social domain theory, and peer relationships. I draw on theories in social psychology as well as social cognitive developmental models. Our lab covers many topics including the developmental origins of conceptions of social inequalities, moral reasoning, and the fair and equal treatment of others.
Additional affiliations
October 2006 - present
University of Kent
Position
  • Honorary Professor of Psychology
August 1994 - present
University of Maryland, College Park
Position
  • Professor

Publications

Publications (226)
Article
Little is known about how group bias may impact children's acceptance of unsubstantiated claims. Most children view cheating as unfair. However, in competitive situations, when ambiguity surrounds the potential intention to cheat, group affiliation may lead children to support claims of cheating based solely on the team affiliation of the claimant,...
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In response to some resource inequalities, children give priority to moral concerns. Yet, in others, children show ingroup preferences in their evaluations and resource allocations. The present study built upon this knowledge by investigating children's and young adults’ (N = 144; 5–6-year-olds, Mage = 5.83, SDage = .97; 9–11-year-olds, Mage = 10.7...
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The present study examined British children’s and adolescents’ individual and perceived group evaluations of a challenger when a member of one’s own group excludes a British national or an immigrant newcomer to the school (Turkish or Australian) from participating in a group activity. Participants included British children ( n = 110, M age in years...
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Social inequalities and human rights are inevitably linked to children’s and adolescents’ healthy development. Children who experience structural and interpersonal inequalities in access to resources and opportunities based on their gender, race, ethnicity, or other group categories are denied the right to fair treatment. We assert that investigati...
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Early and middle adolescents' judgements and reasonings about peers who challenge exclusive and inclusive peer group norms were examined across three studies with varying intergroup contexts. Study 1 participants included (N = 199) non‐Arab American participants responding to an Arab American/non‐Arab American intergroup context. Study 2 included (...
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Investigating socioeconomic status (SES) biases, Nepalese children and adolescents (N = 605, 52% girls, Mage = 13.21, SDage = 1.74) attending schools that varied by SES composition were asked to anticipate whether a peer would include a high or low SES character as a math partner. Novel findings were that students attending mixed SES schools were m...
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The Developing Inclusive Youth program is a classroom-based, individually administered video tool that depicts peer-based social and racial exclusion, combined with teacher-led discussions. A multisite randomized control trial was implemented with 983 participants (502 females; 58.5% White, 41.5% Ethnic/racial minority; Mage = 9.64 years) in 48 thi...
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Children’s understanding of status and group norms influence their expectations about social encounters. However, status is multidimensional and children may perceive status stratification (i.e., high- and low-status) differently across multiple status dimensions (i.e., wealth and popularity). The current study investigated the effect of status lev...
Article
To determine whether children will exclude or punish a peer who creates an unfair advantage in an intergroup team context, four- to ten-year-old participants (N = 120, Mage = 6.87) were assigned a team membership and evaluated unintentional and intentional unfair advantages created by a character. Children were more likely to endorse punishment and...
Article
Incidents of prejudice and discrimination in K–12 schools have increased over the past decade around the world, including the United States. In 2018, more than two-thirds of the 2,776 U.S. educators surveyed reported witnessing a hate or bias incident in their school. Children and adolescents who experience prejudice, social exclusion, and discrimi...
Article
Unfair advantages can be created either intentionally (e.g., cheating) or unintentionally (e.g., unintended benefit). Little is known regarding how children evaluate different types of advantages in situations where group identity and group membership are made salient. To investigate how children’s group identity influences their evaluations and at...
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This study investigated the role of children's gender stereotypes and peer playmate experiences in shaping their desire to play with peers who hold counterstereotypical preferences (e.g., a boy who likes dolls or a girl who likes trucks). Children (N = 95; 46 girls, 49 boys; 67% White, 18% Black, 8% Latinx, 4% Asian, 3% other; median household inco...
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This study investigated adolescents’ expectations about friendships between peers from different socioeconomic status (SES) in Nepal. Overall, Nepalese adolescents (N = 389, Mage = 14.08; grades: 7–10) attributed more negative intentions to high‐SES than to low‐SES peers and expected that parents of high‐SES targets would disapprove of cross‐group...
Article
Around the globe, individuals are affected by exclusion, discrimination, and prejudice targeting individuals from racial, ethnic, and immigrant backgrounds as well as crimes based on gender, nationality, and culture (United Nations General Assembly, 2016). Unfortunately, children are often the targeted victims (Costello & Dillard, 2019). What is no...
Article
This study investigated the socializing influence of peers and parents in interracial encounters by disentangling how children and adolescents consider peer and parent messages when predicting interracial and same‐race inclusion. Black and White children (9–14 years old, N = 246) predicted the likelihood of interracial and same‐race peer inclusion...
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Social exclusion based on negative intergroup attitudes, such as in-group biases and outgroup distrust, can result in long-term negative consequences such as depression, withdrawal, and anxiety, and a low motivation to achieve in school. The development of concepts of fair and equal treatment of others as well as the emergence of cross-group friend...
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Social justice refers to promoting fairness, equality, equity, and rights across multiple aspects of society, including economic, educational, and workforce opportunities. A number of scholars across academia have called for a greater incorporation of social and racial justice approaches to the field of human development and have asserted that soci...
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This study investigated children's and adolescents' predictions regarding intergroup inclusion in contexts where peers differed on two dimensions of group membership: race and wealth. African American and European American participants (N = 153; age range: 8-14 years, Mage = 11.46 years) made predictions about whether afterschool clubs would prefer...
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This study examined the role of group norms, group identity, age, contact, and stereotypes on youths' decisions to include a peer in an intergroup context portraying Lebanese and American adolescents. Lebanese participants (N = 275), ages 12 and 16 years, were surveyed about expectations for inclusion of an out-group target with similar interests o...
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Background While research has documented negative social and academic consequences that occur when students experience peer exclusion, few studies have been conducted to investigate teachers’ evaluations of peer exclusion. Aims This study investigated whether ethnic and gender biases enter teachers’ evaluations of classroom peer exclusion that met...
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Moral reasoning is an essential part of how humans develop and a fundamental aspect of how human societies change over time. On a developmental timescale, reasoning about interpersonal disagreements and dilemmas spurs age-related changes in moral judgments from childhood to adulthood. When asked to distribute resources among others, even young chil...
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Divergent cultural, religious, and ideological beliefs and practices are often challenging to contemplate and difficult to accept when they conflict with an individual's own convictions and way of life. The recognition that children and adolescents grow up in an increasingly diverse world has led to a general interest in fostering tolerance. In thi...
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Children rely on their understanding of others’ mental states to help them navigate complex social contexts involving moral judgments and group membership. This study examined the relationship between mental state understanding, group membership, and moral judgments. Children (4–10 years old, N = 120, MAge = 6.87 years, SDAge = 1.81), were intervie...
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Social inequalities limit important opportunities and resources for members of marginalized and disadvantaged groups. Understanding the origins of how children construct their understanding of social inequalities in the context of their everyday peer interactions has the potential to yield novel insights into when-and how-individuals respond to dif...
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Many people believe in equality of opportunity but overlook and minimize the structural factors that shape social inequalities in the United States and around the world, such as systematic exclusion (e.g., educational, occupational) based on group membership (e.g., gender, race, socioeconomic status). As a result, social inequalities persist and pl...
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Children's evaluations of necessary harm (acts intended to prevent a greater harm) and how maternal disapproval and peer relationship play roles in this context were examined. A total of 120 children at 6, 9, and 12 years of age evaluated scenarios depicting prototypic and necessary (physical or verbal) harm. When a mother was depicted as disapprov...
Article
Morality has two key features: (1) moral judgments are not solely determined by what your group thinks, and (2) moral judgments are often applied to members of other groups as well as your own group. Cooperative motives do not explain how young children reject unfairness, and assert moral obligations, both inside and outside their groups. Resistanc...
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While there is a growing body of research on how individuals evaluate interracial exclusion in offline settings, much less is known about evaluations of interracial exclusion in online settings. This study aimed to address this gap by examining evaluations by male adolescents and young adults (N = 151; Mage = 17.59, standard deviation = 0.50) of in...
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This study investigated children's and adolescents' predictions of inclusion and evaluations of exclusion in interracial and same-race peer contexts. The sample (N = 246) consisted of African American (n = 115) and European American (n = 131) children and adolescents who judged the likelihood of including a new peer, evaluated the group's decision...
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Asian American youth’s inclusion decisions were investigated in cross-ethnic peer contexts (Asian and non-Asian). Ten-, 13-, and 16-year-old participants ( N = 134), enrolled in U.S. schools, decided whether to include a same-ethnic peer with different interests or a different-ethnic peer with similar interests. Findings showed that with age, parti...
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Children and adolescents (N = 153, ages 8–14 years, Mage = 11.46 years) predicted and evaluated peer exclusion in interwealth (high‐wealth and low‐wealth) and interracial (African American and European American) contexts. With age, participants increasingly expected high‐wealth groups to be more exclusive than low‐wealth groups, regardless of their...
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Around the world, the negative consequences of prejudicial attitudes and behavior on child development are extensive. Children who experience unfair treatment, exclusion, discrimination, and victimization are at risk for negative developmental outcomes, including social withdrawal, depression, anxiety, and a lack of motivation to succeed in school....
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Children's and adolescents’ resource allocation was examined in a context of inequality between schools and a peer group norm of either equality or equity. Participants (N = 257; children, 7–11 years old and adolescents, 13–16 years old) were inducted into groups with either a lot (advantaged) or few (disadvantaged) art resources, in the context of...
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Although human societies provide protection from harm and enable the construction of collaborative and mutually beneficial social structures, they also pave the way for social hierarchies that deny equal treatment to certain portions of the population. Moral judgments about fairness and equality, as well as stereotypes, biases, and prejudice, emerg...
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Key constituents of morality emerge during the first 4 years of life. Recent research with infants and toddlers holds a promise to explain the origins of human morality. This article takes a constructivist approach to the acquisition of morality, and makes three main proposals. First, research on moral development needs an explicit definition of mo...
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This study investigated how theory of mind (ToM) competence is related to children's ability to differentiate between intentional and unintentional false statements regarding claims to resources. Participants (4-10 years old; N = 122) heard about individuals who had different access to knowledge about resource ownership when making resource claims,...
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In a hidden inequality context, resource allocators and resource recipients are unaware that an unknowingly advantaged recipient possesses resources. The present study presented children aged 3–13 years (N = 121) with a hidden inequality vignette involving an accidental transgression in which one resource claimant, who unknowingly possessed more re...
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Tomasello’s A Natural History of Morality is novel, compelling, and comprehensive. Drawing on past and current research in developmental psychology, as well as moral philosophy, I make the following points: (1) cooperation is a significant major hallmark of early human sociality but is also the foundation for antagonistic goals designed to enhance...
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This study examined children's and adolescents' reasoning about the exclusion of others in peer and school contexts. Participants (80 8-year-olds, 85 11-year-olds, 74 14-year-olds, and 73 20-year-olds) were asked to judge and reason about the acceptability of exclusion from novel groups by children and school principals. Three contexts for exclusio...
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The present study examined how peer group norms influence children’s developing evaluations of deviant ingroup members. Following the manipulation of competitive or cooperative norms, participants (children, Mage = 8.69; adolescents, Mage = 13.81; adults, Mage = 20.89; n = 263) evaluated deviant ingroup members from their own and the group’s perspe...
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This study investigated patterns of reasoning concerning different types of moral transgressions and drawing on both social domain theory and moral motivation theory in children between six and eight years of age (N = 130). The findings documented different patterns of reasoning for each measure and for transgressions including different moral prin...
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Prosocial behaviors, instances of helping, sharing, and caring, are important for the development and maintenance of social relationships. By exhibiting these positive behaviors toward others, individuals build successful interpersonal relationships, encourage respectful treatment of others, and learn valuable social skills that serve as the buildi...
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The present study investigated the relations between 4- to 6-year-old children’s (N = 67) gender stereotypes, resource allocations, and mental state knowledge in gender stereotypic contexts. Participants were told vignettes about female and male characters completing gender-stereotyped activities (making dolls or trucks). Children held stereotypic...
Chapter
Moral reasoning is integral to morality and its development. We define moral reasoning as the formation of judgments in accordance with principles concerning others' welfare, rights, and fairness. By this definition, moral reasoning is distinct from other types of social reasoning, for instance, reasoning about social conventions and traditions. Co...
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The present study investigated age-related changes in the intergroup allocation of resources depending on whether the ingroup norm was competitive or cooperative. Participants included children (Mage = 8.69), adolescents (Mage = 13.81) and adults (Mage = 20.89), (N = 263) who were inducted into simulated groups and informed about an ingroup norm of...
Article
Children (N = 267, ages 8–14 years, M = 11.61 years, middle to upper-middle income) made predictions regarding groups of same-aged peers from high-wealth and low-wealth backgrounds. The context involved granting access to a special opportunity. From middle childhood to early adolescence children increasingly expected both high- and low-wealth group...
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The current study investigated whether children’s relative social status within a context influences their ability to identify others’ mental states. Across two experiments, 3- to 7-year-olds (N = 103) were randomly assigned to hold either an advantaged or disadvantaged social status and were assessed on their ability to accurately identify others’...
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Youth often hold group norms that perpetuate inequality. One way these norms can be changed is by challenging these norms by choosing to include new members into these groups who hold morally just norms. In the current study, children's and adolescents' inclusion decisions and social reasoning about challenging group norms through inclusion were in...
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In many situations, children evaluate straightforward resource inequalities as unfair. It remains unclear, however, how children interpret hidden inequalities (i.e., inequalities that are unknown to allocators and/or recipients). Children 3- to 9-years-old (N = 87) evaluated and attributed intentions to a naïve resource allocator who, while unaware...
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A developmental approach provides a unique vantage point for understanding the origins, acquisition, and nature of change regarding intergroup attitudes and behavior. Developmental research has focused predominantly on understanding and addressing negative intergroup attitudes and behaviors. We assert that group identity and group dynamics do not h...
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Being a member of a peer group involves making decisions about whom to include in or exclude from the group. Sometimes these decisions are related to whether members of the group support or challenge the norms of the group. To examine how young children weigh concerns for group norms and group membership in both moral and social–conventional norm c...
Chapter
This chapter overviews theory and recent research on the role that group processes play in social exclusion and resource allocation decisions in childhood and adolescence. The Social Reasoning Development (SRD) model draws upon theory and research in both developmental psychology and social psychology. The model integrates and extends social domain...
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Children's perceptions of social resource inequalities were investigated by measuring open-ended explanations for race-based disparities in access to societal resources. Fifth graders (N = 139, M = 11.14 years, SD = 0.61 years) viewed animated vignettes depicting hypothetical resource inequalities between institutions serving children of African-Am...
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Social exclusion based on race and ethnicity occurs within the context of peer relationships beginning in childhood. Surprisingly little is known about the minority youth perspective regarding experiences and evaluations of social exclusion. While it is important to investigate and identify how majority youth’s biases contribute to social exclusion...
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Do young children give priority to following personal beliefs over the testimony of a majority group of adults that approves of social exclusion? Following current research on children’s preference for nondissenters when learning the names for novel objects, this study investigated children’s preference for consensus opinion in two contexts: Interr...
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p> Do young children give priority to following personal beliefs over the testimony of a majority group of adults that approves of social exclusion? Following current research on children’s preference for non-dissenters when learning the names for novel objects, this study investigated children’s preference for consensus opinion in two contexts: In...
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Distinguishing between equity and equality is essential when making social and moral decisions, yet the related neurodevelopmental processes are unknown. Evaluations of contextually based third-party distributions incorporating recipient need and resource importance were examined in children and adolescents (N = 82; 8-16 years). Spatiotemporal neur...
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The fair exchange of resources provides a basis for developing morality, yet research has rarely examined the role of group processes that are central to children's world. In this article, we describe a new perspective as well as research demonstrating that group processes play a key role in the fair allocation of resources among children and adole...
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Age-related changes in young children’s expectations for others’ resource allocation decisions were investigated. Children ages 3 to 6 years (N = 80) were introduced to an inequality of resources between two groups. Participants gave their expectations for (a) how a member of the group with more resources (advantaged group) and a member of the grou...
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Youth peer groups hold many different types of norms, including norms supporting aggressive behavior. Challenging or standing up to such aggressive norms can be difficult for children and adolescents, given the pressures to conform to groups. In the current study, the relationship between individual judgments and expectations of the judgments of a...
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In this article, the authors assert that (a) the topics of equity and justice reflect important areas of developmental science theory and research which have not yet been recognized as central areas of research in child development and developmental science, (b) a concern for social inequalities serves as a common thread binding equity and justice...
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The present study investigated age-related changes regarding children's (N = 136) conceptions of fairness and others' welfare in a merit-based resource allocation paradigm. To test whether children at 3- to 5-years-old and 6- to 8-years-old took others' welfare into account when dividing resources, in addition to merit and equality concerns, childr...
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Children's decisions regarding the allocation of societal resources in the context of preexisting inequalities were investigated. African American and European American children ages 5 to 6 years (n = 91) and 10 to 11 years (n = 94) judged the acceptability of a medical resource inequality on the basis of race, allocated medical supplies, evaluated...
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To investigate whether children rectify social inequalities in a resource allocation task, participants (N=185 African-American and European-American 5-6year-olds and 10-11year-olds) witnessed an inequality of school supplies between peers of different racial backgrounds. Assessments were conducted on how children judged the wrongfulness of the ine...
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Research Findings: To test children’s use of testimony of others, 3 – 9 years (N = 227) made judgments about a potential peer transgression in which the intentions of the protagonist were ambiguous, after hearing two different forms of testimony. The 2 forms of testimony were (a) opposing opinion-based testimony from an adult authority versus a pee...
Chapter
Children around the world are affected by bias, prejudice, and discrimination. In this chapter, we argue that intergroup social exclusion—exclusion of peers on the basis of group membership—is a form of prejudice. As such, research efforts should be directed at uncovering the negative intergroup attitudes that sustain these behaviors, and encouragi...
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Age-related changes in children’s associations of economic resources and race were investigated. The sample (N = 308) included 5-6 year-olds (n = 153, M = 6.01 years, SD = .33 years) and 10-11 year-olds (n = 155, M = 11.12 years, SD = .59 years) of African-American (n = 93), European-American (n = 92), Latino (n = 62), Asian-American (n = 23), and...
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In the context of a pre-existing resource inequality, the concerns for strict equality (allocating the same number of resources to all recipients) conflict with the concerns for equity (allocating resources to rectify the inequality). This study demonstrated age-related changes in children's (3-8 years old, N = 133) ability to simultaneously weigh...
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Why is moral reasoning fundamental to an explanation of the development of morality? Reasoning is the process by which humans create and apply principles for how individuals ought to treat one another; it is neither innate nor inculcated, but constructed through everyday interactions over the course of development.
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Social exclusion and inclusion from groups, as well as the distribution of resources, are fundamental aspects of social life, and serve as sources of conflicts that bear on issues of fairness and equality, beginning in childhood. For the most part, research on social exclusion and allocation of resources has not focused on the issue of group member...
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An important question for psychological science is what types of psychological values guide individuals throughout life, and what factors increase or decrease the importance of these values. This Quartet in Social Development focuses on research that explicitly investigates values as defined by the universal content and structure of values. A centr...
Chapter
Social exclusion is a common occurrence in social life, and this experience begins in childhood. Frequent exclusion in childhood and adolescence is related to long-term negative consequences, such as depression, social withdrawal, and anxiety. Most developmental research in this area has documented how patterns of victimization and bullying behavio...
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To investigate the social cognitive skills related to challenging gender stereotypes, children (N = 61, 3-6 years) evaluated a peer who challenged gender stereotypic norms held by the peer's group. Participants with false belief theory of mind (FB ToM) competence were more likely than participants who did not have FB ToM to expect a peer to challen...
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This study investigated three factors that contribute to social exclusion: group norms, individual characteristics, and stereotypes. Non-Arab American 12- and 16-year-olds (N = 199) judged their expectations about the inclusivity of Arab American and non-Arab American peer groups toward new peers characterized by: (a) different ethnic identity but...
Article
We investigated judgments and emotions in contexts of social exclusion that varied as a function of bystander behaviour (N = 173, 12- and 16-year-olds). Adolescents responded to film vignettes depicting a target excluded by a group with no bystanders, onlooking bystanders, or bystanders who included the target. Adolescents were asked to judge the b...
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Morality and cultural identity emerge during human development in complex ways. We describe the theories and findings that focus on social exclusion and inclusion, social inequalities regarding resource allocation, and intercultural contexts that both bear on and contribute to morality and moral development. This research reveals that individuals v...
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Research indicates that in-group favoritism is prevalent among both adults and children. Although research has documented that individuals do not consistently display an in-group bias, the conditions under which out-group preference exists are not well understood. In this study, participants (N = 462) aged 9 to 16 years judged in-group deviant acts...
Chapter
Morality is a central aspect of social life and has been at the core of psychological theories for more than a century. The scientific study of morality poses enduring questions about how individual psychological needs for autonomy and attachment to groups and society can be met while also ensuring the integrity, dignity, and fair treatment of othe...