A new study published in The Journal of Social Psychology confirms that individuals prefer closer connections with those they perceive as more similar to themselves, even in contexts that emphasize intergroup differences. The research examined attitudes among ethnic, religious, and political groups and found that similarity-attraction theory remains robust regardless of whether diversity or shared traits are celebrated. These findings contribute to our understanding of intergroup relations in increasingly diverse societies.
The study aimed to explore whether the well-established similarity-attraction theory, which suggests people are more drawn to those they perceive as similar, holds true in intergroup settings. While much of the previous research on this topic has focused on interpersonal relationships, the researchers recognized a gap in understanding how this dynamic operates between groups, particularly in modern, diverse societies where multiculturalism often highlights intergroup differences.
“The first issue that inspired the research topic is that many contemporary societies are experiencing increasing diversity,” said study author Raimundo Salas-Schweikart, a magister in public policy and PhD candidate in psychology at Georgetown University.
“In this regard, there has been a lot of research on diversity from a multicultural perspective. In general terms, this research has validated diverse identities, and rightly so. However, this research agenda has neglected that, as human beings, we share several commonalities. Similarity-attraction theory provides a perspective to investigate how the perception of similarities can lead to engaging with different others.”
The researchers conducted four studies, each focusing on a specific group context. Across the studies, a total of 2,664 participants were recruited via an online research platform.
In the first study, the researchers examined the relationship between perceived similarity and desired social closeness among three major ethnic groups in the United States: Black, Hispanic, and White Americans. A total of 231 participants (43% female, average age 34.86 years) were recruited through Prolific Academic. The recruitment criteria included self-identification with one of the three target ethnic groups, residence in the United States, and a balance of political ideologies.
Participants were asked to complete two measures. The first was the Perceived Similarity Index (PSI), which evaluated how similar participants perceived themselves to be to members of an ethnic outgroup across seven dimensions, such as values, culture, and trustworthiness. The second measure, adapted from the Social Distance scale, assessed participants’ willingness to engage with members of the outgroup in scenarios such as becoming friends, neighbors, or colleagues.
Participants were randomly assigned to evaluate one of the other two ethnic groups as the target outgroup. For example, Black participants assessed either Hispanic or White Americans. The study included demographic and political orientation questions to control for these variables in the analysis.
Across Black, Hispanic, and White Americans, participants consistently expressed a desire for closer social relationships with outgroups they perceived as more similar. This pattern held regardless of whether the emphasis was on similarities, differences, or neither.
Study 2 built on the findings of Study 1 by incorporating three experimental conditions: a control condition, a “celebration of differences” condition, and a “celebration of similarities” condition. A larger sample of 823 participants (48% female, average age 30.17 years) was recruited, with the same ethnic group stratification and recruitment procedures as in Study 1.
Participants were randomly assigned to one of the three conditions. In the celebration of differences condition, they read a prompt emphasizing the unique qualities of ethnic groups. In the celebration of similarities condition, the prompt highlighted shared traits among ethnic groups. The control condition provided no framing related to intergroup differences or similarities. As in Study 1, participants completed the PSI and Social Distance measures, evaluating their perceptions and willingness to engage with one of the other two ethnic groups.
The researchers found that the experimental conditions had no significant effect on the relationship between perceived similarity and desired social closeness. Participants in all three conditions consistently showed a preference for closer contact with outgroups they perceived as more similar to themselves.
Importantly, the results replicated the findings from Study 1 with a larger and more diverse sample, reinforcing the robustness of the similarity-attraction paradigm in ethnic intergroup contexts.
Study 3 shifted focus to religious groups, specifically Baptists, Catholics, and Protestants in the United States. A total of 1,004 participants (68% female, average age 37.75 years) were recruited using the same platform and methods as the previous studies. Participants were required to self-identify with one of the three Christian denominations, and recruitment ensured an even distribution across these groups.
The experimental setup mirrored that of Study 2, with participants assigned to the control condition, the celebration of differences condition (highlighting distinctiveness among religious groups), or the celebration of similarities condition (emphasizing commonalities among religious groups). Participants completed the PSI and Social Distance measures, this time evaluating members of one of the other two religious groups.
Across all conditions, the researchers found a consistent negative relationship between perceived similarity and social distance. Participants from all three denominations expressed a preference for closer contact with members of religious outgroups they perceived as more similar to their own group.
Unlike in Study 2, there was a small but notable finding in the celebration of similarities condition for Baptists. Participants in this condition showed an even stronger preference for social closeness with similar others, suggesting that emphasizing commonalities may slightly amplify the effect of similarity-attraction in certain religious contexts. However, this was not observed for Catholics or Protestants.
The fourth study examined the similarity-attraction dynamic within the realm of political ideology. A total of 606 participants (48% female, average age 42.69 years) were recruited, split evenly between self-identified liberals and conservatives. Recruitment criteria included residence in the United States and affiliation with one of the two political orientations.
As in Study 2 and Study 3, participants were randomly assigned to one of three experimental conditions. In the celebration of differences condition, participants read a prompt emphasizing the value of ideological diversity and the distinctiveness of political groups. In the celebration of similarities condition, the prompt highlighted shared values and common goals across the political spectrum. The control condition provided no such framing. Participants completed the PSI and Social Distance measures, evaluating members of the opposing political orientation.
Consistent with the previous studies, the researchers found a robust negative relationship between perceived similarity and social distance. Participants from both political orientations preferred closer contact with outgroup members they perceived as ideologically similar, regardless of whether the experimental condition emphasized differences, similarities, or neither.
The experimental conditions had no significant effect on the similarity-attraction relationship, suggesting that political preferences for similarity are resistant to external framing. This finding is particularly significant given the polarized nature of political discourse in the United States. The results demonstrated that even in a divisive political landscape, people’s preferences for similar others remain stable across ideological lines.
“The strength of perceived similarities was unexpectedly robust,” Salas-Schweikart told PsyPost. “Moreover, it was surprising to find it across political groups since they highlight the differences more than the similarities.”
He highlighted two key takeaways from the findings: “First, the strength and importance of similarities. Across different types of groups (e.g., ethnic, political, religious), similarity predicted closer relations with members of different groups.
“Second, and as a consequence of the first one, given the ubiquitous nature of similarity among groups and its importance in predicting how close the groups are, policymakers could consider similarity attraction when designing policies for the current diverse societies.”
The research highlights that perceived similarity strongly influences preferences for social closeness with outgroup members. But as with all research, there are limitations.
“One important caveat we need to consider is that we used a U.S.-based sample across our studies,” Salas-Schweikart noted. “Samples from other places may yield different outcomes. Therefore, more research is required to explore whether and how similarity-attraction theory holds in non-WEIRD populations.”
Future research could also explore strategies to effectively reduce intergroup bias by leveraging shared identities or examining how similarity-attraction might interact with other factors like group status or cultural norms.
“An important long-term goal is to contribute to the cohesion of diverse societies,” Salas-Schweikart said. “One challenge of diversity is common ground to constitute open and inclusive societies.”
“If the reader wants to explore more about the significance of similarity attraction and the challenge of diversity, they can refer to The Psychology of Multiculturalism, Assimilation, and Omniculturalism: Managing Diversity in Global Context, by one of the paper authors, Prof. Moghaddam,” he added.
The study, “Similarity-attraction across ethnic, religious, and political groups: does celebrating differences or similarities make a difference?“, was authored by Raimundo Salas-Schweikart, Margaret J. Hendricks, Melanie Boychuck, and Fathali M. Moghaddam.
