First KLI Many Labs Grant for the project “Trust under inequality: A many-labs registered report”

The first KLI Many Labs Grant is for the project “Trust under inequality: A many-labs registered report” (project #2025.01) by Leon Hilbert (UvA), Dianna Amasino (TiU), Mirre Stallen (LEI), Laura Hoenig (VU Amsterdam), Angelo Romano (LEI), Leticia Micheli (LEI), Tycho van Tartwijk (LEI), Alan Sanfey (RU), Sarah Vahed (RU), Žiga Puklavec (UvA), Christoph Kogler (TiU), and Giuliana Spadaro (VU Amsterdam).

First update by Leon Hilbert.

Trust under inequality: A many-labs registered report

Economic inequality is rising across the globe. As the gap between rich and poor widens, it not only expands material differences but also threatens social trust—the glue that holds societies together. When people lose trust in each other and in institutions, support for redistributive policies declines, making it even harder to reduce inequality. This can create a vicious cycle: inequality erodes trust, and lower trust reduces the capabilities to reduce inequality.

Our project, funded by the KLI-many-labs grant, aims to understand when and why inequality undermines trust. For example, we suspect that how inequality arises—whether through merit or luck—plays a key role. People often see merit-based inequality as fairer than inequality caused by luck or privilege, and these fairness perceptions might also shape how much people trust one another. Moreover, we expect that the extent of inequality at the macro level (e.g., one’s society) affects trust, such that the level of trust between unequals might depend on whether one is part of a relatively advantaged or disadvantaged society.

To test these mechanisms, we will conduct a large, multi-lab behavioral experiment across five Dutch universities. Participants will make incentivized decisions about how much to trust and reciprocate across several rounds of interaction. We will examine how trust develops (or breaks down) over time when players start with unequal resources, and whether these dynamics differ depending on whether inequality was earned (merit-based) or randomly assigned (luck-based). Moreover, we will leverage the many-labs approach to vary “societal differences” in inequality between the sub-samples from the different labs, and have participants interact within and between societies.

We aim to submit a stage 1 registered report this academic year and will keep you posted on the developments of this project.