Timing uncertainty in collective risk dilemmas encourages group reciprocation and polarization

Social dilemmas are often shaped by actions involving uncertain returns
only achievable in the future, such as climate action or voluntary
vaccination. In this context, uncertainty may produce non-trivial effects.
Here, we assess experimentally — through a collective risk dilemma — the
effect of timing uncertainty, i.e. how uncertainty about when a target
needs to be reached affects the participants’ behaviours. We show that
timing uncertainty prompts not only early generosity but also polarised
outcomes, where participants’ total contributions are distributed
unevenly. Furthermore, analysing participants’ behaviour under timing
uncertainty reveals an increase in reciprocal strategies. A data-driven
game-theoretical model captures the self-organizing dynamics underpinning
these behavioural patterns. Timing uncertainty thus casts a shadow on the
future that leads participants to respond early, while reciprocal
strategies appear to be important for group success. Yet, the same
uncertainty also leads to inequity and polarisation, necessitating the
inclusion of new incentives handling these societal issues.

社会困境往往由涉及仅在未来才能获得的不确定回报的行为所塑造，例如气候行动或自愿接种疫苗。在此类情境中，不确定性可能产生不容忽视的影响。本研究依托集体风险困境实验范式，对时间不确定性的效应开展实验评估——即目标达成时限的不确定性如何影响参与者的行为表现。研究结果表明，时间不确定性不仅会催生早期的慷慨行为，还会引发极化结果：参与者的总贡献额分布极不均衡。此外，对时间不确定性情境下参与者行为的分析显示，互惠策略的使用占比显著提升。一款基于数据驱动的博弈论模型，可捕捉支撑上述行为模式的自组织动力学机制。由此可见，时间不确定性如同给未来蒙上一层阴影，促使参与者提前做出响应；而互惠策略似乎对群体达成目标至关重要。但与此同时，这类不确定性同样会引发不公平与极化现象，因此亟需引入新的激励机制以应对此类社会议题。