The primary goal of the Center for Decision Research is to support the highest quality behavioral science research. The pursuit of this goal is animated by a dispassionate search for truths to help people make wiser choices and lead better lives. The CDR is committed to making these inquiries and insights open to all people in order to obtain a full and accurate understanding of the human condition. The following collection of behavioral science research by CDR faculty examines issues related to racism, prejudice, stereotyping, and intergroup relations.

Bertrand, Marianne & Mullainathan, Sendhil (2016). This Problem Has a Name: Discrimination. Chicago Booth Review.

“We responded to more than 1,300 employment ads in the sales, administrative support, clerical, and customer-services job categories—and found that white names received 50 percent more callbacks for interviews. Our evidence indicated that hiring managers were discriminating against African Americans on the basis of their names.”

Tuller, Hannah & Bryan, Christopher & Heyman, Gail & Christenfeld, Nicholas. (2015). Seeing the Other Side Perspective Taking and the Moderation of Extremity. Journal of Experimental Social Psychology, 59.

“Recognizing the reasonableness of others' positions is important for conflict reduction, but is notoriously hard. We tested a perspective-taking approach to decreasing attitude entrenchment. Participants were held account- able in a task in which they wrote about a controversial issue from the perspective of a partner with an opposing viewpoint. This approach was effective at changing views on controversial issues—in Study 1 on weight discrimination, an issue participants were unlikely to have thought much about, and in Study 2 on abortion, where beliefs tend to be more deeply held. Studies 3 and 4 showed this change only took place under conditions where participants met the individual with an opposing view in person, and where that individual would see the perspective-taking effort. These results suggest that it is possible to reduce attitude entrenchment by encouraging people to think about the opposing perspective of another, as long as there is real contact and accountability.”

Schroeder, J., & Epley, N. (in press). Demeaning: Dehumanizing others by minimizing the importance of their psychological needs. Journal of Personality and Social Psychology.

"We document a tendency to “demean” others’ needs: believing that psychological needs—those requiring mental capacity, and hence more uniquely human (e.g., need for meaning and autonomy)—are relatively less important to others compared to physical needs—those shared with other biological agents, and hence more animalistic (e.g., need for food and sleep). Because valuing psychological needs requires a sophisticated humanlike mind, agents presumed to have relatively weaker mental capacities should also be presumed to value psychological needs less compared to biological needs. Supporting this, our studies found that people demeaned the needs of non-human animals (e.g., chimpanzees) and historically dehumanized groups (e.g., drug addicts) more than the needs of close friends or oneself (Studies 1 and 3). Because mental capacities are more readily recognized through introspection than by external observation, people also demean peers’ needs more than their own, inferring that one’s own behavior is guided more strongly by psychological needs than identical behavior in others (Study 4). Two additional experiments suggest that demeaning could be a systematic error (Studies 5 and 6), as charity donors and students underestimated the importance of homeless people’s psychological (versus physical) needs compared to self-reports and choices from homeless people. Underestimating the importance of others’ psychological needs could impair the ability to help others. These experiments indicate that demeaning is a unique facet of dehumanization reflecting a reliable, consequential, and potentially mistaken understanding of others’ minds."

Schroeder, J., Kardas, M., & Epley, N. (2017). The humanizing voice: Speech reveals, and text conceals, a more thoughtful mind in the midst of disagreement. Psychological Science, 28, 1745-1762.

“A person’s speech communicates his or her thoughts and feelings. We predicted that beyond conveying the contents of a person’s mind, a person’s speech also conveys mental capacity, such that hearing a person explain his or her beliefs makes the person seem more mentally capable—and therefore seem to possess more uniquely human mental traits—than reading the same content. We expected this effect to emerge when people are perceived as relatively mindless, such as when they disagree with the evaluator’s own beliefs. Three experiments involving polarizing attitudinal issues and political opinions supported these hypotheses. A fourth experiment identified paralinguistic cues in the human voice that convey basic mental capacities. These results suggest that the medium through which people communicate may systematically influence the impressions they form of each other. The tendency to denigrate the minds of the opposition may be tempered by giving them, quite literally, a voice.”

Eyal, T., & Epley, N. (2017). Exaggerating accessible differences: When gender stereotypes overestimate actual group differences. Personality and Social Psychology Bulletin, 43, 1323-1336.

“Stereotypes are often presumed to exaggerate group differences, but empirical evidence is mixed. We suggest exaggeration is moderated by the accessibility of specific stereotype content. In particular, because the most accessible stereotype contents are attributes perceived to differ between groups, those attributes are most likely to exaggerate actual group differences due to regression to the mean. We tested this hypothesis using a highly accessible gender stereotype: that women are more socially sensitive than men. We confirmed that the most accessible stereotype content involves attributes perceived to differ between groups (pretest), and that these stereotypes contain some accuracy but significantly exaggerate actual gender differences (Experiment 1). We observe less exaggeration when judging less accessible stereotype content (Experiment 2), or when judging individual men and women (Experiment 3). Considering the accessibility of specific stereotype content may explain when stereotypes exaggerate actual group differences and when they do not.”

Steinmetz, J., Touré-Tillery, T., & Fishbach, A. (in press). The first-member heuristic: Group members labeled “first” influence judgment and treatment of groups. Journal of Personality and Social Psychology.

"People often make judgments about a group (e.g., immigrants from a specific country) based on information about a single group member. Seven studies (N = 1,929) tested the hypothesis that people will expect the performance of an arbitrarily ordered group to match that of the group member in the first position of a sequence more closely than that of group members in other positions. This greater perceived diagnosticity of the first member will in turn affect how people treat the group. This pattern of judgment and treatment of groups, labeled the “first-member heuristic,” generalized across various performance contexts (e.g., gymnastic routine, relay race, and job performance), and regardless of whether the focal member performed poorly or well (Studies 1–3). Consistent with the notion that first members are deemed most informative, participants were more likely to turn to the member in the first (vs. other) position to learn about the group (Study 4). Further, through their disproportionate influence on the expected performance of other group members, first members’ performances also influenced participants’ support for policies that would benefit or hurt a group (Study 5) and their likelihood to join a group (Study 6). Finally, perceived group homogeneity moderated the first-member heuristic, such that it attenuated for nonhomogeneous groups (Study 7)."

Koch, A., Dorrough, A., Glöckner, A., & Imhoff, R. (in press). The ABC of society: Similarity in agency and beliefs predicts cooperation across groups. Journal of Experimental Social Psychology.

The dimensions that explain which societal groups cooperate more with which other groups remain unclear. We predicted that perceived similarity in agency / socioeconomic success and conservative-progressive beliefs increases cooperation across groups. Self-identified members (N = 583) of 30 society-representative U.S. groups (gays, Muslims, Blacks, upper class, women, Democrats, conservatives etc.) played an incentivized one-time continuous prisoner’s dilemma game with one self-identified member of each of these groups. Players knew nothing of each other except one group membership. Consistent with the ABC (agency-beliefs-communion) model of spontaneous stereotypes, perceived self-group similarity in agency and beliefs independently increased expected and actual cooperation across groups, controlling for shared group membership. Similarity in conservative-progressive beliefs had a stronger effect on cooperation than similarity in agency, and this effect of similarity in beliefs was stronger for individuals with extreme (progressive or conservative) compared to moderate beliefs.

Koch, A., Imhoff, R., Unkelbach, C., Nicolas, G., Fiske, S., Terache, J., Carrier, A., & Yzerbyt, V. (in press). Groups’ warmth is a personal matter: Understanding consensus on stereotype dimensions reconciles adversarial models of social evaluation. Journal of Experimental Social Psychology.

As proponents of two theories of social evaluation, we disagree whether people spontaneously differentiate societal groups’ conservative-progressive beliefs (distinct claim of the agency-beliefs-communion or ABC model) or warmth/communion (distinct claim of the stereotype content model or SCM). Our adversarial collaboration provides one way to resolve this debate. Examining people from four continents who differentiated groups in their country (N = 2,356), we found lower consensus on groups’ warmth/communion compared to agency/~competence and beliefs (Studies 1 4). Consensus on groups’ warmth/communion was lower because people differed in self-rated agency and beliefs, and they inferred groups’ warmth/communion from perceived similarity in agency and beliefs between the groups and the self (Studies 5-8). Previous ABC studies only examined consensual differentiation of groups and thereby did not find evidence for spontaneous differentiation of groups’ warmth/communion. Instead, we next examined non-consensual (personal) differentiation of groups: People spontaneously differentiated groups by their agency/~competence, beliefs, and also warmth/communion (Studies 7 and 8). Based on these data, the ABC model and SCM concede that people spontaneously differentiate groups’ warmth/communion and beliefs, respectively, providing one way to resolve the models’ debate.

Koch, A., Kervyn, N., Kervyn, A. & Imhoff, R. (2018). Studying the cognitive map of the U.S. states: Ideology and prosperity stereotypes predict interstate prejudice. Social Psychological & Personality Science, 9, 530 538.

What are the spontaneous stereotypes that U.S. citizens hold about the U.S. states? We complemented insights from theory-driven approaches to this question with insights from a novel data-driven approach. Based on pile sorting and spatial arrangement similarity ratings for the states, we computed two cognitive maps of the states. Based on ratings for the states on*20 candidate dimensions, we interpreted the dimensions that spanned the two maps (Studies 1 and 2). Consistent with the agency/socioeconomic success, conservative-progressive beliefs, and communion (ABC) model of spontaneous stereotypes, these dimensions that participants spontaneously used to rate the states’ similarity included prosperity (A) and ideology (B)stereotypes (states seen as more liberal and atheist were seen as more educated and wealthy). Study 3 showed that states seen as more average on A and B were stereotyped as more likable. Additionally, Study 3 showed that interstate similarity in stereotypic ideology and prosperity mattered, as it predicted interstate prejudice.

Imhoff, R., Koch, A., & Flade, F. (2018). (Pre)occupations: A data-driven map of jobs and its consequences for categorization and evaluation. Journal of Experimental Social Psychology, 77, 76-88.

We present a data-driven model of stereotypes about occupations (total N = 3919). Across two classification systems and national contexts (U.S.; Germany), we show remarkable convergence in the stereotype dimensions spontaneously employed to make sense of occupational groups (agency; progressiveness). Further studies show that these dimensions reflect presumed characteristics of job holders and not just describe their occupational role (Study 2), and that proximity of occupations on the emerging stereotype model increased superordinate categorization (Study 3) and contagious transfer of (positive and negative) valence from one occupation to another (Study 4). Together these studies do not only provide important insights into the perception of one of the most ubiquitous social taxonomies but also provide a rich, open access dataset for researchers seeking to employ occupational groups as a tool to better understand stereotypes and intergroup relations in general.

Alves, H., Koch, A., & Unkelbach, C. (2018). A cognitive-ecological explanation of intergroup biases. Psychological Science, 29, 1126-1133.

People often hold negative attitudes toward out-groups and minority groups. We argue that such intergroup biases may result from an interaction of basic cognitive processes and the structure of the information ecology. This cognitive-ecological model assumes that groups such as minorities and out-groups are often novel to a perceiver. At the level of cognition, novel groups are primarily associated with their unique attributes, that is, attributes that differentiate them from other groups. In the information ecology, however, unique attributes are likely to be negative. Thus, novel groups, and by proxy minorities and out-groups, tend to be associated with negative attributes, leading to an evaluative disadvantage. We demonstrated this disadvantage in three experiments in which participants successively formed impressions about two fictional groups associated with the same number of positive and negative attributes. Participants preferred the first group over the novel group as long as the groups’ unique attributes were negative.

Imhoff, R., Koch, A. (2017). How orthogonal are the Big Two of social perception? On the curvilinear relationship between agency and communion. Perspectives on Psychological Science, 12, 122-137.

Humans make sense of their social environment by forming impressions of others that allow predicting others’ actions. In this process of social perception, two types of information carry pivotal importance: other entities’ communion (i.e., warmth and trustworthiness) and agency (i.e., status and power). Although commonly thought of as orthogonal dimensions, we propose that these Big Two of social perception are curvilinearly related. Specifically, as we delineate from four different theoretical explanations, impressions of communion should peak at average agency, while entities too high or too low on agency should be perceived as low on communion. We show this pattern for social groups across one novel and five previously published datasets, including a meta-analysis of the most comprehensive data collection in the group perception literature consisting of 36 samples from 20+ countries. Addressing the generalizability of this curvilinear relation, we then report recent and unpublished experiments establishing the effect for the perception of individuals and animals. Based on the proposed curvilinear relation we revisit the primacy of processing communion (rather than agency) information. Finally, we discuss the possibility of a more general curvilinear relation between communion and dimensions other than agency.

Koch, A., & Imhoff, R., Dotsch, R., Alves, H., & Unkelbach, C. (2016). The ABC of stereotypes about groups: Agency / socio-economic success, conservative progressive beliefs, and communion. Journal of Personality & Social Psychology, 110, 675-709.

Previous research argued that stereotypes differ primarily on the two dimensions of warmth/communion and competence/agency. We identify an empirical gap in support for this notion. The theoretical model constrains stereotypes a priori to these two dimensions; without this constraint, participants might spontaneously employ other relevant dimensions. We fill this gap by complementing the existing theory-driven approaches with a data-driven approach that allows an estimation of the spontaneously employed dimensions of stereotyping. Seven studies (total N= 4451) show that people organize social groups primarily based on their agency/ socio-economic success (A), and as a second dimension, based on their conservative-progressive beliefs (B). Communion(C) is not found as a dimension by its own, but rather as an emergent quality in the two-dimensional space of A and B, resulting in a two-dimensional ABC model of stereotype content about social groups.

Obermeyer, Ziad & Powers, Brian & Vogeli, Christine & Mullainathan, Sendhil. (2019). Dissecting racial bias in an algorithm used to manage the health of populations. Science, 366.

“Health systems rely on commercial prediction algorithms to identify and help patients with complex health needs. We show that a widely used algorithm, typical of this industry-wide approach and affecting millions of patients, exhibits significant racial bias: At a given risk score, Black patients are considerably sicker than White patients, as evidenced by signs of uncontrolled illnesses. Remedying this disparity would increase the percentage of Black patients receiving additional help from 17.7 to 46.5%. The bias arises because the algorithm predicts health care costs rather than illness, but unequal access to care means that we spend less money caring for Black patients than for White patients. Thus, despite health care cost appearing to be an effective proxy for health by some measures of predictive accuracy, large racial biases arise. We suggest that the choice of convenient, seemingly effective proxies for ground truth can be an important source of algorithmic bias in many contexts.”

Devin G. Pope, Joseph Price, Justin Wolfers (2018). Awareness Reduces Racial Bias. Management Science 64(11):4988-4995.

"Can raising awareness of racial bias subsequently reduce that bias? We address this question by exploiting the widespread media attention highlighting racial bias among professional basketball referees that occurred in May 2007 following the release of an academic study. Using new data, we confirm that racial bias persisted in the years after the study’s original sample but prior to the media coverage. Subsequent to the media coverage, though, the bias disappeared. Several potential mechanisms may have produced this result, including voluntary behavior changes by individual referees, adjustments by players to new information, and changes in referee behavior due to institutional pressure. These results suggest a new kind of Hawthorne effect in which greater scrutiny of even subtle forms of bias can bring about meaningful change."

Small, D. A., Pope, D. G., & Norton, M. I. (2012). An age penalty in racial preferences. Social Psychological and Personality Science, 3(6), 730–737.

“The authors document an age penalty in racial discrimination: Charitable behavior toward African American children decreases—and negative stereotypical inferences increase—with the age of those children. Using data from an online charity that solicits donations for school projects, the authors found that proposals accompanied by images of older African American students (Grades 6–12) led to fewer donations than proposals with images of younger African Americans (pre-K-Grade 5), with the opposite pattern for proposals with images of multiples races or of all White students. A laboratory experiment demonstrated that negative stereotypical beliefs about African Americans (e.g., that they are lazy) increased with age more for African American children than for White children, a pattern that predicted decreases in giving.”

Feasel, S. H., Risen, J. L., & White, S. M. (2019). Tied to both sides or asserting a preferred identity? The case of Palestinian citizens of Israel in an intergroup contact setting. Self and Identity, 1-24.

"Research shows that individuals with dual identities have the potential to serve as a gateway between the groups represented by their dual identity, reducing bias between opposing sides. But does this potential necessarily exhibit itself in an intergroup contact setting where all groups are present? We study Palestinian Citizens of Israel (PCI) at Seeds of Peace, a three-week program with PCI, Jewish Israeli, and Palestinian teens. By analyzing which camp participants the PCI list as close and which participants list PCI as close, we find that PCI associate with Palestinians at an especially high rate. Importantly, PCI are even more popular among Palestinians and less popular among Jewish Israelis than are Palestinians. We explain these results with an identity assertion hypothesis in which the PCI assert their Palestinian identity through their relationships."

Schroeder, J., & Risen, J. L. (2016). Befriending the enemy: Outgroup friendship longitudinally predicts intergroup attitudes in a co-existence program for Israelis and Palestinians. Group Processes and Intergroup Relations, 19, 72-93.

"One of the largest Middle East coexistence programs annually brings together Israeli and Palestinian teenagers for a 3-week camp in the United States. For 3 years, we longitudinally tracked how this intervention affected Israelis’ and Palestinians’ relationships with, and attitudes toward, each other. Specifically, we measured participants’ outgroup attitudes immediately before and after camp, and, for 2 years, 9 months following “reentry” to their home countries. In all 3 years, participants’ attitudes toward the outgroup improved from precamp to postcamp. Participants who formed an outgroup friendship during camp developed more positive feelings toward outgroup campers, which generalized to an increase in positivity toward all outgroup members. Although the positivity faded upon campers’ reentry, there was significant residual positivity after reentry compared to precamp. Finally, positivity toward the outgroup after reentry was also predicted by outgroup friendships. Future contact interventions may profit from encouraging individuals to make and maintain outgroup friendships."

Critcher, C. R., & Risen, J. L. (2014). If he can do it, so can they: Incidental exposure to counterstereotypically-successful exemplars prompts automatic inferences. Journal of Personality and Social Psychology, 106, 359-379.

"After incidental exposure to Blacks who succeeded in counterstereotypical domains (e.g., Brown University President Ruth Simmons, Nobel Laureate Toni Morrison), participants drew an automatic inference that race was not a success-inhibiting factor in modern society. Of note, participants’ automatic inferences were not simply guided by their explicit reasoning (i.e., their beliefs about what these exemplars signify about the state of race relations). Studies 1–3 demonstrated the basic automatic inference effect and provided evidence that such effects unfolded automatically, without intention or awareness. Study 4 replicated the effect in non-race-related domains. Subsequent studies examined what features of exemplars (Studies 5 and 6) and inference makers (Studies 7 and 8) prompt automatic inferences. Study 5 suggested that counterstereotypically successful exemplars prompt racism-denying inferences because they signal what is possible, even if not typical. Study 6 demonstrated that when these exemplars succeed in a stereotypical domain (e.g., Blacks in athletics), similar automatic inferences are not drawn. Those most likely to draw automatic inferences are people predisposed to approach the world with inferential thinking: participants dispositionally high in need for cognition (Study 7) or experimentally primed to think inferentially (Study 8)"

Risen, J. L., & Gilovich, T., Dunning, D. (2007). One-shot illusory correlations and stereotype formation. Personality and Social Psychology Bulletin, 33, 1492-1502.

"In four studies, the authors explored the emergence of one-shot illusory correlations—in which a single instance of unusual behavior by a member of a rare group is sufficient to create an association between group and behavior. In Studies 1, 2, and 3, unusual behaviors committed by members of rare groups were processed differently than other types of behaviors. They received more processing time, prompted more attributional thinking, and were more memorable. In Study 4, the authors obtained evidence from two implicit measures of association that one-shot illusory correlations are generalized to other members of a rare group. The authors contend that one-shot illusory correlations arise because unusual pairings of behaviors and groups uniquely prompt people to entertain group membership as an explanation of the unusual behavior."

Heller, Sara & Shah, Anuj & Guryan, Jonathan & Ludwig, Jens & Mullainathan, Sendhil & Pollack, Harold. (2017). Thinking, Fast and Slow? Some Field Experiments to Reduce Crime and Dropout in Chicago. The Quarterly Journal of Economics, 132. 1-54.

“We present the results of three large-scale randomized controlled trials (RCTs) carried out in Chicago, testing interventions to reduce crime and dropout by changing the decision-making of economically disadvantaged youth. We study a program called Becoming a Man (BAM), developed by the non-profit Youth Guidance, in two RCTs implemented in 2009–10 and 2013– 15. In the two studies participation in the program reduced total arrests during the intervention period by 28–35%, reduced violent-crime arrests by 45–50%, improved school engagement, and in the first study where we have follow-up data, increased graduation rates by 12–19%. The third RCT tested a program with partially overlapping components carried out in the Cook County Juvenile Temporary Detention Center (JTDC), which reduced readmission rates to the facility by 21%. These large behavioral responses combined with modest program costs imply benefit-cost ratios for these interventions from 5-to-1 up to 30-to-1 or more. Our data on mechanisms are not ideal, but we find no positive evidence that these effects are due to changes in emotional intelligence or social skills, self-control or “grit,” or a generic mentoring effect. We find suggestive support for the hypothesis that the programs work by helping youth slow down and reflect on whether their automatic thoughts and behaviors are well suited to the situation they are in, or whether the situation could be construed differently.”

Shah, Anuj & Mullainathan, Sendhil & Shafir, Eldar. (2012). Some Consequences of Having Too Little. Science, 338. 682-5.

“Poor individuals often engage in behaviors, such as excessive borrowing, that reinforce the conditions of poverty. Some explanations for these behaviors focus on personality traits of the poor. Others emphasize environmental factors such as housing or financial access. We instead consider how certain behaviors stem simply from having less. We suggest that scarcity changes how people allocate attention: It leads them to engage more deeply in some problems while neglecting others. Across several experiments, we show that scarcity leads to attentional shifts that can help to explain behaviors such as overborrowing. We discuss how this mechanism might also explain other puzzles of poverty.”

Correll, Joshua & Park, Bernadette & Judd, Charles & Wittenbrink, Bernd. (2007). The influence of stereotypes on decisions to shoot. European Journal of Social Psychology, 37. 1102 - 1117.

“Using a videogame to simulate encounters with potentially hostile targets, three studies tested a model in which racial bias in shoot/don’t-shoot decisions reflects accessibility of the stereotype linking Blacks to danger. Study 1 experimentally manipulated the race-danger association by asking participants to read newspaper stories about Black (vs. White) criminals. As predicted, exposure to stories concerning Black criminals increased bias in the decision to shoot. Studies 2 and 3 manipulated the number of White and Black targets with and without guns in the context of the videogame itself. As predicted, frequent presentation of stereotypic (vs. counterstereotypic) targets exacerbated bias (Study 2) and—consistent with our process account—rendered stereotypes more accessible (Study 3).”

Ma, Debbie & Correll, Joshua & Wittenbrink, Bernd. (2018). The effects of category and physical features on stereotyping and evaluation. Journal of Experimental Social Psychology, 79. 42-50

“Stereotyping and prejudice researchers have provided numerous demonstrations that the greater a target's prototypicality, the more similar attitudes and inferences will be to the attitudes and stereotypes perceivers have about the group. However, research to date has yet to also test for a possible quadratic association relating target prototypicality to judgment. The current research offers an extension of existing research by testing for both linear and quadratic relationships between target prototypicality and stereotyping using an implicit measure of stereotyping. In Study 1, we tested for linear and quadratic associations between racial prototypicality and stereotyping of Black and White males, while also manipulating the valence of the stereotypes. Study 2 offered a conceptual replication of Study 1 and tested for linear and quadratic associations between gender prototypicality and stereotyping of White males and White females, while again manipulating the valence of these gender stereotypes. Across both studies we replicated previous research showing a positive, linear effect of proto- typicality on stereotyping, such that targets greater in prototypicality elicited greater stereotyping. We also found evidence of a quadratic effect of prototypicality, such that average prototypic targets elicited the most stereotyping. Finally, we observed that negative, rather than positive, stereotypes drove both the linear and quadratic effects we report.”

White, Shannon M. & Schroeder, Juliana & Risen, Jane L. (2020). When “Enemies” Become Close: Relationship Formation Among Palestinians and Jewish Israelis at a Youth Camp. Journal of Personality and Social Psychology, (In Press).

"Having close relationships with outgroup members is an especially powerful form of intergroup contact that can reduce prejudice. Rather than examine the consequences of forming close outgroup relationships, which has previously been studied as part of intergroup contact theory, we examine how outgroup relationships—relative to ingroup relationships—form in the first place. We collected seven years of data from Jewish Israeli and Palestinian teenagers attending a three-week summer camp at Seeds of Peace, one of the largest conflict transformation programs in the world. We tested how being assigned to share an activity group (e.g., bunk, table, dialogue group) influenced relationship formation among outgroup pairs (Jewish Israeli-Palestinian) compared to ingroup pairs (Israeli-Israeli, Palestinian-Palestinian). Existing research offers competing theories for whether propinquity is more impactful for the formation of ingroup or outgroup relationships; here, we found propinquity was significantly more impactful for outgroup relationships. Whereas two ingroup participants were 4.46 times more likely to become close if they were in the same versus different bunk, for example, two outgroup participants were 11.72 times more likely to become close. We propose that sharing an activity group is especially powerful for more dissimilar dyads because people are less likely to spontaneously engage with outgroup members in ways that promote relationships. Thus, structured, meaningful engagement can counteract homophily. Furthermore, in this setting, propinquity proved to be an even better predictor of outgroup (vs. ingroup) relationship formation than that pair’s initial outgroup attitudes. We discuss theoretical and practical implications for intergroup processes and relationship formation."