Abstract: Intergenerational cooperation refers to the behavior where individuals sacrifice their present interests for the benefit of future others. It is a decision-making process that necessitates decision-makers to weigh the value of their current interests against the interests of future generations, ultimately making decisions that contribute to sustainable development. To encourage individuals, societies, and nations to adopt sustainable intergenerational cooperation practices, it is crucial to deeply understand the psychological mechanisms that influence people's willingness to forego short-term benefits in favor of intergenerational cooperation.
This study examines the distinctions between intertemporal decision-making, social decision-making, and the role of both option attributes and the choice process in these areas. It demonstrates that intergenerational cooperation encompasses not only the assessment of value in intertemporal and social decision-making but also highlights its distinctive characteristics in the choice stage. By examining the role of decision-making mechanisms, we highlight the significance of temporal and social discounting in the value assessment phase of intergenerational cooperation. Individuals tend to prefer immediate (albeit smaller) payoffs compared to larger delayed payoffs, indicating a tendency toward temporal discounting. Additionally, individuals tend to underestimate the returns to others (especially future generations) and overestimate personal returns, reflecting the phenomenon of social discounting. This dual psychological discounting in the temporal and social domains presents a significant challenge to intergenerational cooperation.
Despite the fact that existing literature typically considers temporal and social discounting separately, their combined impact on intergenerational cooperation has not been adequately addressed. The interaction between these two dimensions constitutes a core, complex, and multidimensional discounting mechanism in intergenerational decision-making. Moreover, their influence on ultimate value choices is nonlinear; the transition from value assessment to final decision-making is subject to complex regulation by dynamic mechanisms that remain underexplored. Contrary to discounting theories that posit that increased temporal and social distance leads to personal benefit maximization, empirical evidence unveils a more nuanced reality. In contexts involving the welfare and survival of future generations, the expected degree of discounting does not intensify, suggesting the presence of intricate dynamic mechanisms that encourage balanced decision-making and underscore the potential for intergenerational cooperation.
However, there is a notable lack of in-depth research on the motivational mechanisms driving intergenerational cooperation across temporal and social dimensions. This gap hinders a clear explanation of the observed reduction in discount rates in specific contexts, thereby limiting our understanding of the motivational mechanisms behind intergenerational decision-making and the precise formulation of strategies to promote intergenerational cooperation. To bridge this gap, we integrate temporal and social discounting into a unified decision theory, analyzing two pivotal mechanisms during the value assessment phase of intergenerational cooperation: the interaction mechanism of discounting, which examines how temporal and social discounting influence each other and jointly shape intergenerational decision-making, and the internal motivational mechanism, which explores how complex dynamic regulation impacts final intergenerational cooperation decisions.
By elucidating the interaction patterns between discounting in temporal and social dimensions and exploring their underlying dynamic mechanisms, we propose the following strategies to foster intergenerational cooperation: establishing "mental accounts" and "imagining future generations" to balance short-term and long-term interests in resource allocation, regulate the influence of internal and external factors, and quantify the extent of individual sacrifice for intergenerational goals. We have formulated the "Discount-Dynamic-Nudge" model to encapsulate these insights.
Expanding upon the "Mental Accounting" strategy, we advocate for a transformative approach that inspires individuals to allocate resources thoughtfully, prioritizing the welfare of future generations. This approach aims to mitigate temporal discounting, the tendency to prioritize immediate gains over long-term benefits. By embracing "Intergenerational Mental Accounting," we encourage individuals to reframe their decision-making processes, giving greater consideration to the future consequences of their choices. By introducing the concept of "Imagining Future Generations," we cultivate a profound sense of responsibility and kinship with those yet unborn, fostering empathy that mitigates social discounting. We delve into the policy and societal implications of this mindset, emphasizing the urgency for strategies that reconcile individual actions with collective long-term aspirations. This shift in mindset, coupled with deepened intergenerational identification, aligns individual decisions with broader, long-term objectives, fostering a more sustainable and equitable future for all.
In conclusion, we advocate for a lifespan perspective to deepen our understanding of the relationship between intergenerational cooperation discounts and dynamic mechanisms. We recommend a comprehensive approach to measuring intergenerational cooperation that integrates discounting mechanisms, dynamic models, and direct assessments of intergenerational cooperation levels, thereby advancing the theory and practice of intergenerational cooperation.

Key words: intergenerational cooperation, temporal discount, social discount, dynamic mechanisms, nudge