Vicken Hillis

Innovation, Cooperation, and the Perceived Benefits and Costs of Sustainable Agriculture Practices

A central goal of most sustainable agriculture programs is to encourage growers to adopt practices that jointly provide economic, environmental, and social benefits. Using surveys of outreach professionals and wine grape growers, we quantify the perceived costs and benefits of sustainable viticulture practices recommended by sustainability outreach and certification programs. We argue that the mix of environmental benefits, economic benefits, and economic costs determine whether or not a particular practice involves decisions about innovation or cooperation. Decision making is also affected by the overall level of knowledge regarding different practices, and we show that knowledge gaps are an increasing function of cost and a decreasing function of benefits. How different practices are related to innovation and cooperation has important implications for the design of sustainability outreach programs. Cooperation, innovation, and knowledge gaps are issues that are likely to be relevant for the resilience and sustainability of many different types of social-ecological systems.

Linking knowledge and action through mental models of sustainable agriculture.

Significance Sustainability is notoriously difficult to define and put into practice in the context of agricultural and other social-ecological systems. A crucial task within this debate is to analyze how practitioners understand the idea of sustainability. Using California winegrape growers as an example, this paper uses network science to describe the structure of farmer mental models of sustainable agriculture and link those models to behavioral aspects of sustainable agriculture. California growers have hierarchically organized mental models with more abstract goals in the center and more concrete strategies in the periphery. The concept of sustainability is a viable approach for linking knowledge to action; there are strong positive correlations between the sophistication of an individual’s beliefs about sustainability, participation in local outreach programs, and adoption of sustainable practices. Linking knowledge to action requires understanding how decision-makers conceptualize sustainability. This paper empirically analyzes farmer “mental models” of sustainability from three winegrape-growing regions of California where local extension programs have focused on sustainable agriculture. The mental models are represented as networks where sustainability concepts are nodes, and links are established when a farmer mentions two concepts in their stated definition of sustainability. The results suggest that winegrape grower mental models of sustainability are hierarchically structured, relatively similar across regions, and strongly linked to participation in extension programs and adoption of sustainable farm practices. We discuss the implications of our findings for the debate over the meaning of sustainability, and the role of local extension programs in managing knowledge systems.

Cultural group selection follows Darwin's classic syllogism for the operation of selection

The main objective of our target article was to sketch the empirical case for the importance of selection at the level of groups on cultural variation. Such variation is massive in humans, but modest or absent in other species. Group selection processes acting on this variation is a framework for developing explanations of the unusual level of cooperation between non-relatives found in our species. Our case for cultural group selection (CGS) followed Darwins classic syllogism regarding natural selection: If variation exists at the level of groups, if this variation is heritable, and if it plays a role in the success or failure of competing groups, then selection will operate at the level of groups. We outlined the relevant domains where such evidence can be sought and characterized the main conclusions of work in those domains. Most commentators agree that CGS plays some role in human evolution, although some were considerably more skeptical. Some contributed additional empirical cases. Some raised issues of the scope of CGS explanations versus competing ones.

The Role of Pest Control Advisers in Preventative Management of Grapevine Trunk Diseases

Vineyards with trunk diseases (Botryosphaeria dieback, Esca, Eutypa dieback, and Phomopsis dieback) can have negative returns in the long run. Minimizing economic impacts depends on effective management, but adopting a preventative practice after infection occurs may not improve yields. Pest control advisers may reduce grower uncertainty about the efficacy of and need for prevention, which often entails future and unobservable benefits. Here, we surveyed advisers in California to examine their influence over grower decision-making, in the context of trunk diseases, which significantly limit grape production and for which curative practices are unavailable. Our online survey revealed adviser awareness of high disease incidence, and reduced yields and vineyard lifespan. Advisers rated both preventative and postinfection practices positively. Despite higher cost estimates given to postinfection practices, advisers did not recommend preventative practices at higher rates. High recommendation rates were instead correlated with high disease incidence for both preventative and postinfection practices. Recommendation rates declined with increasing cost for preventative, but not for postinfection, practices. Our findings suggest that even when advisers acknowledge the risks of trunk diseases, they may not recommend preventative practices before infection occurs. This underscores the importance of clear outreach, emphasizing both the need for prevention and its long-term cost efficacy.

Adoption as a social marker: Innovation diffusion with outgroup aversion

ABSTRACT Social identities are among the key factors driving behavior in complex societies. Signals of social identity are known to influence individual behaviors in the adoption of innovations. Yet the population-level consequences of identity signaling on the diffusion of innovations are largely unknown. Here we use both analytical and agent-based modeling to consider the spread of a beneficial innovation in a structured population in which there exist two groups who are averse to being mistaken for each other. We investigate the dynamics of adoption and consider the role of structural factors such as demographic skew and communication scale on population-level outcomes. We find that outgroup aversion can lead to adoption being delayed or suppressed in one group, and that population-wide underadoption is common. Comparing the two models, we find that differential adoption can arise due to structural constraints on information flow even in the absence of intrinsic between-group differences in adoption rates. Further, we find that patterns of polarization in adoption at both local and global scales depend on the details of demographic organization and the scale of communication. This research has particular relevance to widely beneficial but identity-relevant products and behaviors, such as green technologies, where overall levels of adoption determine the positive benefits that accrue to society at large.

Preventative Disease Management and Grower Decision Making: A Case Study of California Wine-Grape Growers

Preventative disease management is challenging to farmers because it requires paying immediate costs in the hopes of returning uncertain future benefits. Understanding farmer decision making about prevention has the potential to reduce disease incidence and minimize the need for more costly postinfection practices. For example, the grapevine trunk-disease complex (esca, Botryosphaeria dieback, Eutypa dieback, and Phomopsis dieback) significantly affects vineyard productivity and longevity. Given the chronic nature of the infections and inability to eradicate the fungal pathogens, the preventative practices of delayed pruning, applications of pruning-wound protectants, and double pruning (also known as prepruning) are the most effective means of management. We surveyed wine-grape growers in six regions of California on their use of these three practices. In spite of acknowledging the yield impacts of trunk diseases, a substantial number of respondents either choose not to use preventative practices or incorrectly adopted them in mature vineyards, too late in the disease cycle to be effective. Growers with more negative perceptions of cost efficacy were less likely to adopt preventative practices or were more likely to time adoption incorrectly in mature vineyards. In general, preventative management may require strong intervention in the form of policy or extension to motivate behavioral change.

Success biased imitation increases the probability of effectively dealing with ecological disturbances

Ecological disturbances (i.e. pests, invasive species, floods, fires etc.) are a fundamental challenge in managing connected social-ecological systems. Even if treatment for such disturbances is available, often managers do not act quickly enough or not at all. In this paper we build an agent based model that examines: a) under what circumstances are managers locked into non-action that favors ecological disturbances? b) what learning strategies are most effective in avoiding management lock-in? The model we develop relates adoption of treatment strategies to eradicate ecological disturbances with the type of learning preferred by individuals (success bias, conformist and individual). We further model treatment strategy adoption as a function of treatment cost, ability of the ecological system to recover once treated and the disturbance effect on the social system. Our model shows the importance of success-bias imitation and system size in affecting the odds of eradicating ecological disturbances on connected landscapes.

Breeding Cooperation: Cultural Evolution in an Intergenerational Public Goods Experiment

This paper investigates the evolution of cooperation across multiple laboratory generations in an experimental public goods game. Theories of cultural evolution show how cooperative equlibria can be supported by the transmission of behavioral norms across generations. These types of cultural evolutionary processes are important for political science topics ranging from public policy to political participation. One of the best-established findings in the massive literature on experimental social dilemmas is that within-game communication increases cooperation. We find that it is possible to breed cooperation by selectively exposing later generations of subjects to cooperative messages from previous generations. We propose a number of potential reasons for the fact that between-generation communication (or advice) is at least as strong as within-game communication.

Applying a cultural multilevel selection framework to the adoption of sustainable management practices in California viticulture

In light of the ongoing environmental impacts of agriculture, understanding farmer adoption of sustainable management practices (SMPs) is an important priority. Relatively little work in agricultural adoption has explicitly examined the multilevel dynamics of adoption decision-making. Yet because many SMPs involve cooperative dilemmas—they are individually costly but provide group benefits—understanding the dynamics of both individual and group level behavioral change is critical. In this paper, we argue that cultural evolutionary theory is well suited to examining the emergence and spread of cooperative SMPs, and we illustrate this claim by applying a cultural multilevel selection (CMLS) framework to the adoption of SMPs on the part of winegrape growers in California, USA. Using survey data from over 800 winegrape growers in 3 regions, we estimate the individual-level costs and group-level benefits of 44 different SMPs. We then relate this to variation in their adoption within and between winegrape growing regions to characterize the scope for cultural group selection of the various practices. We also identify a number of mechanisms that might plausibly explain the observed patterns of variation, including various forms of cultural group selection. We highlight the added value of this perspective with respect to the established approaches and outline the data requirements for researchers to conduct similar studies in other settings. Our results underscore the potential for a cultural evolutionary perspective to shed light on the multiscale mechanisms driving adoption of SMPs and, more generally, the promise of cultural evolutionary approaches to supplement existing analytical toolkits in sustainability science.

Managing ecological disturbances: Learning and the structure of social- ecological networks

Abstract Ecological disturbances (i.e. pests, fires, floods, biological invasions, etc.) are a critical challenge for natural resource managers. Land managers play a key role in altering the rate and extent of disturbance propagation. Ecological disturbances propagate across the landscape, while management strategies propagate across social networks of managers. Here we use an agent-based model to examine the joint diffusion of ecological disturbances and management strategies across a social-ecological network, accounting for the fundamental role of social-ecological feedbacks. We examine the management of a generic ecological disturbance as a function of different learning strategies and the social-ecological network. Our approach provides a general scaffold that can be modified to examine a variety of processes in which both social and ecological flows propagate across a social-ecological network. Our findings highlight the importance of full and accurate information to assess successful strategy, limited clustering and alignment between the social and the ecological system.