The rejection-identification model (RIM; Branscombe, Schmitt, & Harvey, 1999) is supported by a number of previous studies (e.g., Schmitt, Branscombe, Kobrynowicz, & Owen, 2002; Schmitt, Spears, & Branscombe, 2003). This suggests that rejection by an outgroup can lead minority group members to identify more with their ingroup, thereby buffering them from the negative effects of discrimination. However, contradictory findings have been produced by other research (e.g., Eccleston & Major, 2006; Major, Quinton, & Schmader, 2003; McCoy & Major, 2003; Sellers & Shelton, 2003), suggesting that the relationship between rejection and identification is far from being completely understood. In the present study, we followed a cohort of 113 international students for a period of 2 years. The study sought to extend the previous work in two important ways. First, it examined the RIM within a longitudinal perspective. Second, building on important work on the multidimensionality of social identification (e.g., Ellemers, Kortekaas, & Ouwerkerk, 1999; Jackson, 2002), it tested the RIM using a three-dimensional approach to group identification. Results supported the predictions of the RIM and indicated that perceived discrimination causes minority group identification and not the reverse. The multidimensional approach also served to reveal a specific effect of discrimination on the cognitive components of identification.

Humans have evolved cognitive processes favoring homogeneity, stability, and structure. These processes are, however, incompatible with a socially diverse world, raising wide academic and political concern about the future of modern societies. With data comprising 22 y of religious diversity worldwide, we show across multiple surveys that humans are inclined to react negatively to threats to homogeneity (i.e., changes in diversity are associated with lower self-reported quality of life, explained by a decrease in trust in others) in the short term. However, these negative outcomes are compensated in the long term by the beneficial influence of intergroup contact, which alleviates initial negative influences. This research advances knowledge that can foster peaceful coexistence in a new era defined by globalization and a socially diverse future. social diversity | trust | intergroup contact | well-being | health G lobal modernization has dramatically changed the demographic composition of most countries (1-3). Societies are in constant flux and current levels of intercultural exchange are transforming social ecosystems (4). Pessimistic appraisals about the potential effects of these changes have dominated recent and critical geopolitical events (e.g., the election of Donald Trump as president in the United States, Brexit in the United Kingdom, and the refugee crisis globally), but it is not yet known how living in a socially diverse world affects the quality of people's lives.Models of human evolution applied to social diversity (1) support the notion that adaptation to a socially diverse context may be problematic and lead to negative outcomes. According to these models, the human brain evolved to sustain motivated cognition and behavior relevant to ingroup survival and cooperation, and to defend against potential threats from unknown outgroups (5). Humans are predisposed to distinguish ingroups from outgroups and this dichotomy is adaptive given that survival is contingent upon cooperation and reciprocity from other ingroup members (6, 7). Perhaps to facilitate this dichotomization, humans have evolved a preference for homogeneity and stability (8), as well as being with similar others (9). Moreover, outgroups are approached with a degree of uncertainty (10), as unknown others could be friends or foes, and caution in new encounters could dictate one's survival. This reasoning is substantiated by influential work in the social sciences showing that interpersonal trust and social cohesion are lower in ethnically heterogeneous communities (11-13). Subsequent work across multiple disciplines expanded on these findings by revealing that social diversity is associated with conflict (14) and may have negative implications for economic growth (15) and public goods provision (16). The mechanism hypothesized to underlie these outcomes is that diversity erodes social cohesion and trust in others (17). Meta-analyses in the field of psychology substantiate this reasoning by demonstrating that, at least initially, intergroup ...

With globalization and immigration, societal contexts differ in sheer variety of resident social groups. Social diversity challenges individuals to think in new ways about new kinds of people and where their groups all stand, relative to each other. However, psychological science does not yet specify how human minds represent social diversity, in homogeneous or heterogenous contexts. Mental maps of the array of society’s groups should differ when individuals inhabit more and less diverse ecologies. Nonetheless, predictions disagree on how they should differ. Confirmation bias suggests more diversity means more stereotype dispersion: With increased exposure, perceivers’ mental maps might differentiate more among groups, so their stereotypes would spread out (disperse). In contrast, individuation suggests more diversity means less stereotype dispersion, as perceivers experience within-group variety and between-group overlap. Worldwide, nationwide, individual, and longitudinal datasets (n= 12,011) revealed a diversity paradox: More diversity consistently meant less stereotype dispersion. Both contextual and perceived ethnic diversity correlate with decreased stereotype dispersion. Countries and US states with higher levels of ethnic diversity (e.g., South Africa and Hawaii, versus South Korea and Vermont), online individuals who perceive more ethnic diversity, and students who moved to more ethnically diverse colleges mentally represent ethnic groups as more similar to each other, on warmth and competence stereotypes. Homogeneity shows more-differentiated stereotypes; ironically, those with the least exposure have the most-distinct stereotypes. Diversity means less-differentiated stereotypes, as in the melting pot metaphor. Diversity and reduced dispersion also correlate positively with subjective wellbeing.

This study explores how researchers’ analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers’ expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each team’s workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers’ results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings.