Conference Agenda

We study how decision-makers that exploit coupled human–natural systems respond to shocks and how attribution of shocks to human or natural causes affects decisions. The small-scale fisheries at Lake Victoria are a prototypical case: the livelihoods of fishers depend on ecological dynamics that they themselves shape through their harvesting choices. In a lab-in-the-field experiment, fishers are randomly exposed to a payoff shock that differs only in its causal origin (human, natural, or joint) while holding material incentives and probabilities constant.

We identify two main patterns. First, experiencing the shock reduces exploitation in a subsequent, identical situation. Second, this behavioral response tends to be stronger for human caused shocks than for natural shocks and is demonstrably weakest when jointly caused by human and natural factors. We further examine whether these effects are explained by individuals’ locus of control. Locus of control predicts baseline system exploitation, but does not explain behavioral adjustment or moderate attribution effects. Our findings provide experimental evidence that causal attribution can shape responses to shocks in coupled human–natural systems.

Inspired by fertilizer use, we investigate behavior in settings where externalities arise from individual activities crossing an uncertain individual threshold. We show within an analytic model that only threshold uncertainty causes individual and social interests to diverge with individuals accepting a larger probability of crossing the threshold than is socially optimal. We then theoretically investigate the impact of information on thresholds as well as taxing the caused externalities for fertilizer use. We test our predictions within an experiment with farmers as well as with students. We find that, even without any regulation in place, farmers invest significantly less than their payoff maximizing level, but on average close to the social optimum. The probability of exceeding the individual threshold and the resulting damages significantly decrease when subjects are provided free informative signals or have to pay for caused damages. In contrast, taxing inputs (fertilizer use) does not decrease the risk of causing external effects.

The increase in waste generation has posed significant challenges to waste management systems worldwide. Effective waste management can be achieved through efficient source sorting. Based on the mandatory waste management policy of China, we design and experimentally test three policy-related informational nudges, focusing on public health, potential penalties, and sorting achievement, to encourage waste sorting behaviors among urban residents. Additionally, we record household daily water and energy consumption to assess behavioral spillover effects. We find that nudges have a significant impact on improving residents’ waste sorting behaviors. However, results are inconclusive regarding spillover effects. Overall, our findings underline the importance of nudging in directly improving environmentally sensitive behaviors but raise doubts about spillover effects. For policymakers, signaling the effectiveness of sorting is suggested, as the efficacy nudge provides a cost-effective intervention.

Climate chang is one of the contemporary collective action challenges in both global and local settings. In this study, we focus on smallholder farmers in rural Ethiopia who use micro-irrigation systems in deteriorating landscapes and engage in integrated watershed management to address climatic and non-climatic challenges. We examined the effect of ex-ante mutual insurance network on collective action, farmers’ investment in watershed management, under erratic drought scenarios. We conduct a lab-in-the-field experiment with 490 randomly selected smallholder farmers in Southern Ethiopia using a dynamic irrigation game. Farmers participated in one of four experimental arms: (i) drought risk, (ii) mutual insurance, (iii) mutual insurance + drought risk, and (iv) base treatment. The results show that the effects of drought risk alone or drought risk combined with mutual insurance on farmers’ investment and water extraction is negative and statistically significant. Mutual insurance alone does not significantly increase investment. A close look into heterogeneity reveals that the effect of mutual insurance on investment in watershed management depends on the position of farmers (upstream and downstream) and degree of social preferences (reciprocity). Furthermore, while drought risk decreases investment when it is moderate drought but increases investment when it is severe or extreme. With predicted increase in extreme weather events, these results have implications on farmers’ collective action on watershed management.