Why even good teams start to perform worse over time
Researchers have found that people in groups often start out cooperating actively, but over time this mindset gradually wanes - even if the external conditions remain good. This is important because the problem may not be money or rules, but the motivation to work together needs to be constantly renewed.
The authors of the study analysed the operation of a group microcredit system in Sierra Leone. In this model, a group rather than an individual receives a loan, and if one member stops paying, the entire group risks losing access to new loans. Researchers tracked the behaviour of 7,108 borrowers in 1,589 groups and studied 47,931 payments over five years.
The details
It turns out that co-operation doesn't usually break down overnight. The researchers describe it as "intermittent decline": within one loan cycle, participants initially pay in a disciplined manner, but then their willingness to help the group gradually declines. When a new loan cycle begins and people are again reminded of their shared responsibility, co-operation rebounds sharply. But then the decline repeats - and in subsequent cycles, it often happens even faster.
In the authors' estimation, it wasn't so much that people were short of money, but rather that the willingness to put in effort for the sake of others waned over time. Participants were inclined to continue to pay their own share, but the willingness to "backstop" someone else on the team declined markedly faster. In interviews, people described this as being relaxed, stubborn, or losing the mindset of collective responsibility.
Why it matters
The research shows that collaboration is not a stable state that is switched on once and then works itself out. Rather, it requires regular "refreshing": reminders, resetting of rules, a common focus and a sense of mutual responsibility.
This is not only important for microcredit. The conclusions can be transferred to work teams, communities, collaborative projects and any group where the result depends on the continuous contribution of many people. Even if the system is initially well established, collaborative work can slowly fall apart without a clear external cause.
Background
The paper was published in Nature, and an accompanying commentary in the same journal emphasises the main conclusion: collaboration in humans constantly goes through cycles of decay and recovery, so it cannot be considered something that persists automatically after a successful start.
Source
Nicholas Sabin, David Klinowski, Felix Reed-Tsochas, Punctuated decline of human cooperation, Nature (2026). Comment: Jiabin Wu, Human cooperation undergoes constant breakdown and repair, Nature (2026).