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I am a social psychologist who uses advanced quantitative methods to answer new questions about intergroup contact, social identity, social injustice, and social change.

I studied psychology and social sciences at the University College Maastricht (BA) and the University of Oxford (MSc, DPhil). After completing my DPhil (PhD) in 2019, I worked as a postdoctoral researcher at the University of Oxford, before starting my current position as a postdoctoral researcher at the University of Southern California.

My name is pronounced KNEELS (Nils) RYE-mer (Reimer).


Intergroup contact and social change

I study how positive and negative contact shape support for social change in advantaged and disadvantaged groups. I found that positive contact encourages solidarity-based collective action among the advantaged, while negative contact encourages collective action among the disadvantaged (Reimer et al., 2017). I am writing up results from a preregistered meta-analysis on this topic.

Intergroup contact and social identity

I study whether intergroup contact changes not only how we see others, but also how we see ourselves. In my thesis, I examined, for example, whether contact with sexual and gender minorities fosters more continuous and fluid conceptions of sexuality and gender. I found evidence that contact with caste and religious outgroups fosters more inclusive national identities which, in turn, are associated with more positive intergroup relations (Reimer et al., in press).


I study whether large-scale contact-based interventions can improve intergroup relations. I evaluated whether the National Citizen Service, a government-funded program that reaches 1 in 6 adolescents in England and Northern Ireland, improves interethnic relations. I also evaluated whether the Shared Education program improves intercommunal relations in Northern Ireland.

Responses to social injustice

I have begun studying double standards in how advantaged-group members judge protest actions by disadvantaged-group members as well as defensive responding to being confronted with one’s role in maintaining social injustice.

Network of my collaborators around the world.


Bayesian Data Analysis

I use Bayesian data analysis (implemented in Stan) as a flexible and powerful approach to statistical inference. I have experience with multilevel, multivariate, logistic and ordinal regression, item response, and missing data models—as well as various combinations of these approaches. I use cross-validation and stacking to compare and combine model predictions.

Prior, likelihood, and posterior distributions for parameter p (the probability of heads) after observing k = 6 heads in n = 10 coin flips.

Multilevel Models

I use multilevel models to solve a broad range of data analysis challenges—including nested data, longitudinal data, and multiple comparison problems. I taught multilevel modeling to graduate students at University of Oxford.

Each person’s probability of observing heads, estimated with complete pooling (left), partial pooling (middle), and no pooling (right) across ten persons. Multilevel models result in partial pooling, and thus overcome multiple comparison problems.

Structural Equation Models

I use structural equation models (lavaan, Mplus) for scale development and to analyse longitudinal surveys. I have experience with cross-lagged panel models, latent growth models, and with more recent approaches to modeling longitudinal data.

Data Visualization

I use ggplot2 as a flexible approach to data visualization. I have experience with a broad range of visualizations, including maps, networks, and flow diagrams. I taught data visualisation to graduate students at University of Oxford.

Example of a data visualization for a recent paper.

Social Network Analysis

I use longitudinal social network analysis to study the co-evolution of same-group friendships, other-group friendships, and political attitudes in disadvantaged minorities. I am learning a lot from Chloe Bracegirdle whom I am co-supervising.

Social network showing segregation by gender (shape) and by ethnicity (colour) in a secondary-school year group.

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