New study shows how — and why — cooperation declines over time

Saïd Business School, University of Oxford

Universidad de Santiago de Chile

William & Mary

News release

New research published in Nature uncovers why cooperation between people often unravels over time, even when groups have strong incentives to contribute to a common goal. The study from Oxford University’s Saïd Business School, Universidad de Santiago de Chile, and William & Mary, reveals that cooperation does not simply erode gradually—it declines and rebounds over many cycles, driven by behavioural shifts rather than purely strategic calculation or financial constraints.

‘In everyday life people often face a simple choice: contribute their share or let someone else carry the load. This research improves our understanding of why cooperation is prone to falling apart,’ says first author Nicholas Sabin, an Associate Professor of Behavioral Science at the Universidad de Santiago de Chile. ‘Ultimately, our findings may point to better solutions for sustaining cooperation in the long term.’

The five-year field study, conducted with a microfinance institution in Sierra Leone, tracked over 47,000 repayment transactions made by more than 7,000 borrowers operating under a joint‑liability lending system. In this structure, borrowers must cooperate each month to ensure that the group’s loan is fully repaid, or all members lose access to future credit.

‘Group lending offers an ideal, real-work test of how cooperation evolves in groups. Unlike research in the artificial context of a lab experiment, the stakes are high. Failing to contribute can have significant economic and social consequences,’ says David Klinowski, Assistant Professor of Economics at William & Mary and a co-author of the study.

The study found that cooperation within borrower groups consistently:

• Started high, as members were motivated and attentive to their collective responsibilities.
• Gradually declined, as members became ‘tired,’ ‘relaxed,’ or more tempted to free‑ride on others’ efforts.
• Surged back to high levels each time the group began a new loan cycle and was formally reminded (or resensitized) to the consequences of non-cooperation.
• Declined faster each cycle, as cooperative behaviour for individuals habituated to reminders and cooperative motivation decayed more quickly.

The authors named this consistent pattern—cooperation eroding, rebounding, then eroding again more rapidly— ‘punctuated decline’.

Contrary to prevailing theories which suggest that declining cooperation is a sign of rational learning or strategic planning, the study showed that behavioural decay best explained the long-term patterns. The researchers also conducted and analysed interviews with 73 microfinance clients and staff, which include detailed descriptions of borrowers' motivations and reasons for cooperating or defecting in the group.

Why this matters

The consequences of choosing to ‘carry your load’ and cooperate come up in a broad range of different contexts. In healthcare, the question of cooperation can determine who donates blood or gets vaccinated. In politics, it influences willingness to vote. At the level of nation states, it plays a role in determining whether countries abide by international agreements. In public policy, it affects how public projects are funded.

‘Although our research was conducted in a very specific setting, we believe that it captures fundamental aspects of human behaviour and may be relevant to many forms of everyday cooperation,’ says senior author Felix Reed-Tsochas, Professor of Complex Systems at Oxford University’s Saïd Business School and a Fellow of Green Templeton College. ‘In the long-term, sustained cooperation depends on keeping motivation alive.’

The findings provide some of the strongest field evidence to date that human cooperation is shaped by shifting motivational states, not just rational incentives. The researchers suggest that institutions relying on long-term cooperation could mitigate decline by introducing strategic ‘resets’, building habits and intrinsic motivation, and automating cooperative behaviours where possible.

Contact Information

For interview or comment from Felix Reed-Tsochas or Nicholas Sabin: Lisa Speckhard-Pasque, Research Communications Manager at Oxford Saïd, Elisabeth.speckhard-pasque@sbs.ox.ac.uk or 7860-948681 

About Saïd Business School:  Saïd Business School at the University of Oxford is a vibrant and innovative business school, embedded within a 900-year-old world leading university. We create programmes and ideas that have global impact and reach. We educate leaders, change makers and innovators across every industry and sector. Our groundbreaking research and exceptional teaching transforms individuals, who transform businesses, which transforms the world. We create impact from within. 

About the Facultad de Administración y Economía at the Universidad de Santiago de Chile: Since its creation in 1972, the Faculty of Management and Economics has been engaged, at the most advanced level, in the creation, preservation, development, and transmission of knowledge in the fields of management, accounting and auditing, economics, and public management and policy. It is guided by the comprehensive development of its students, academics, and staff, within an ethical and social framework that prioritizes respect for human beings and social responsibility.

About William & Mary: Founded by Royal Charter in 1693, William & Mary is America’s first university. The Alma Mater of the Nation brings together the breadth of a public liberal arts and sciences education with the innovation of a preeminent global research university. Here, curiosity deepens into wisdom, shaping lives of meaning, distinction and purposeful impact. For more than 300 years, the university has convened great minds and hearts to meet the most pressing needs of our time.