Malthouse, Eugene
ORCID: https://orcid.org/0000-0001-5665-7501, Pilgrim, Charlie
ORCID: https://orcid.org/0000-0002-3800-677X, Sgroi, Daniel
ORCID: https://orcid.org/0000-0001-9575-2640, Accerenzi, Michela
ORCID: https://orcid.org/0000-0002-1163-3132, Alfonso, Antonio
ORCID: https://orcid.org/0000-0002-5396-3711, Ashraf, Rana Umair
ORCID: https://orcid.org/0000-0002-0152-8419, Baard, Max
ORCID: https://orcid.org/0009-0004-2836-7936, Banerjee, Sanchayan
ORCID: https://orcid.org/0000-0002-0176-0429, Belianin, Alexis
ORCID: https://orcid.org/0000-0002-0874-8393, Bhattacharjee, Swagata
ORCID: https://orcid.org/0009-0007-8540-474X, Bhattacharya, Mihir
ORCID: https://orcid.org/0000-0002-9813-671X, Brañas-Garza, Pablo
ORCID: https://orcid.org/0000-0001-8456-6009, Cárdenas, Juan-Camilo
ORCID: https://orcid.org/0000-0003-0005-7595, Carriquiry, Miguel
ORCID: https://orcid.org/0000-0002-1032-8056, Choi, Syngjoo
ORCID: https://orcid.org/0000-0003-4006-0377, Clochard, Gwen-Jiro
ORCID: https://orcid.org/0009-0004-5513-4193, Denzon, Eduardo Ezekiel
ORCID: https://orcid.org/0009-0006-0072-3489, Dessoulavy-Sliwinski, Bartlomiej
ORCID: https://orcid.org/0000-0002-4395-9815, Dini, Giorgio
ORCID: https://orcid.org/0009-0000-2514-3129, Dong, Lu
ORCID: https://orcid.org/0000-0001-9785-2442, Ertl, Antal
ORCID: https://orcid.org/0000-0002-8371-8418, Exadaktylos, Filippos
ORCID: https://orcid.org/0000-0001-7339-8847, Filiz-Ozbay, Emel
ORCID: https://orcid.org/0000-0003-3099-2971, Flecke, Sarah Lynn
ORCID: https://orcid.org/0009-0008-1402-2207, Galeotti, Fabio
ORCID: https://orcid.org/0000-0003-0221-5470, Garcia-Muñoz, Teresa
ORCID: https://orcid.org/0000-0003-1778-254X, Hanaki, Nobuyuki
ORCID: https://orcid.org/0000-0003-3127-690X, Hollard, Guillaume
ORCID: https://orcid.org/0000-0001-7994-4546, Horn, Dániel
ORCID: https://orcid.org/0000-0002-2888-6240, Huang, Lingbo
ORCID: https://orcid.org/0000-0003-2713-6867 and Kiss, Hubert János
ORCID: https://orcid.org/0000-0003-3666-9331
(2026)
The private solution trap in collective action problems across 34 nations.
Proceedings of the National Academy of Sciences of the United States of America, 123
(12).
DOI 10.1073/pnas.2504632123
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Official URL: https://doi.org/10.1073/pnas.2504632123
Abstract
Collective action problems emerge when individual incentives and group interests are misaligned, as in the case of climate change. Individuals involved in these problems are generally considered to have two options: contribute toward public solutions such as global warming mitigation or free ride. However, many collective action problems today involve a third option of investing in a “private solution” such as local adaptation. The availability of this third option can lead to a private solution trap whereby private solutions are adopted, collectively optimal public solutions are not provided, and existing inequalities are exacerbated. We investigated the private solution trap with a collective action game featuring private and public solutions, wealth inequality determined by luck or merit, and participants from 34 countries. We found that the joint existence of private solutions and wealth inequality had a consistent effect across countries: Participants given a higher endowment adopted private solutions almost twice as often as those given a lower endowment, regardless of whether it was determined by luck or merit, and contributed proportionally less toward public solutions. Wealth inequality increased in every country and those given lower endowments were often left unprotected as public solutions were not provided. Across countries, cultural values of hierarchy and harmony were associated with preferences for private and public solutions, respectively. We also identified two universal pathways toward public solution provision: early contributions and conditional cooperation. Our findings highlight the ubiquity of the private solution trap, its cultural underpinnings, and its potential consequences for global collective action problems.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | human cooperation; social dilemma; climate change; private solutions; cross- cultural study |
| Divisions: | Institute of Economics |
| Subjects: | Ecology Sociology |
| Funders: | European Union’s Horizon Europe program, European Research Council |
| Projects: | 101089107 - GREEN TIPPING Consolidator Grant, ERC- AdG 101020453 PRINCIPLES |
| DOI: | 10.1073/pnas.2504632123 |
| ID Code: | 12730 |
| Deposited By: | MTMT SWORD |
| Deposited On: | 14 Apr 2026 14:50 |
| Last Modified: | 14 Apr 2026 14:50 |
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