Bert Baumgaertner

Defining and simulating open-ended novelty: requirements, guidelines, and challenges

The open-endedness of a system is often defined as a continual production of novelty. Here we pin down this concept more fully by defining several types of novelty that a system may exhibit, classified as variation, innovation, and emergence. We then provide a meta-model for including levels of structure in a system’s model. From there, we define an architecture suitable for building simulations of open-ended novelty-generating systems and discuss how previously proposed systems fit into this framework. We discuss the design principles applicable to those systems and close with some challenges for the community.

On nonepistemic values in conservation biology

Conservation biology is a uniquely interdisciplinary science with strong roots in ecology, but it also embraces a value-laden and mission-oriented framework. This combination of science and values causes conservation biology to be at the center of critique regarding the disciplines scientific credibility-especially the division between the realms of theory and practice. We identify this dichotomy between seemingly objective (fact-based) and subjective (value-laden) practices as the measure-value dichotomy, whereby measure refers to methods and analyses used in conservation biology (i.e., measuring biodiversity) and value refers to nonepistemic values. We reviewed and evaluated several landmark articles central to the foundation of conservation biology and concepts of biodiversity with respect to their attempts to separate measures and values. We argue that the measure-value dichotomy is false and that conservation biology can make progress in ways unavailable to other disciplines because its practitioners are tasked with engaging in both the realm of theory and the realm of practice. The entanglement of measures and values is by no means a weakness of conservation biology. Because central concepts such as biodiversity contain both factual and evaluative aspects, conservation biologists can make theoretical progress by examining, reviewing, and forming the values that are an integral part of those concepts. We suggest that values should be included and analyzed with respect to the methods, results, and conclusions of scientific work in conservation biology.

Opinion strength influences the spatial dynamics of opinion formation

ABSTRACT Opinions are rarely binary; they can be held with different degrees of conviction, and this expanded attitude spectrum can affect the influence one opinion has on others. Our goal is to understand how different aspects of influence lead to recognizable spatio-temporal patterns of opinions and their strengths. To do this, we introduce a stochastic spatial agent-based model of opinion dynamics that includes a spectrum of opinion strengths and various possible rules for how the opinion strength of one individual affects the influence that this individual has on others. Through simulations, we find that even a small amount of amplification of opinion strength through interaction with like-minded neighbors can tip the scales in favor of polarization and deadlock.

The influence of political ideology and trust on willingness to vaccinate

In light of the increasing refusal of some parents to vaccinate children, public health strategies have focused on increasing knowledge and awareness based on a “knowledge-deficit” approach. However, decisions about vaccination are based on more than mere knowledge of risks, costs, and benefits. Individual decision making about vaccinating involves many other factors including those related to emotion, culture, religion, and socio-political context. In this paper, we use a nationally representative internet survey in the U.S. to investigate socio-political characteristics to assess attitudes about vaccination. In particular, we consider how political ideology and trust affect opinions about vaccinations for flu, pertussis, and measles. Our findings demonstrate that ideology has a direct effect on vaccine attitudes. In particular, conservative respondents are less likely to express pro-vaccination beliefs than other individuals. Furthermore, ideology also has an indirect effect on immunization propensity. The ideology variable predicts an indicator capturing trust in government medical experts, which in turn helps to explain individual-level variation with regards to attitudes about vaccine choice.

Planning horizon affects prophylactic decision-making and epidemic dynamics

The spread of infectious diseases can be impacted by human behavior, and behavioral decisions often depend implicitly on a planning horizon—the time in the future over which options are weighed. We investigate the effects of planning horizons on epidemic dynamics. We developed an epidemiological agent-based model (along with an ODE analog) to explore the decision-making of self-interested individuals on adopting prophylactic behavior. The decision-making process incorporates prophylaxis efficacy and disease prevalence with the individuals’ payoffs and planning horizon. Our results show that for short and long planning horizons individuals do not consider engaging in prophylactic behavior. In contrast, individuals adopt prophylactic behavior when considering intermediate planning horizons. Such adoption, however, is not always monotonically associated with the prevalence of the disease, depending on the perceived protection efficacy and the disease parameters. Adoption of prophylactic behavior reduces the epidemic peak size while prolonging the epidemic and potentially generates secondary waves of infection. These effects can be made stronger by increasing the behavioral decision frequency or distorting an individual’s perceived risk of infection.

Social media echo chambers and satisfaction with democracy among Democrats and Republicans in the aftermath of the 2016 US elections

ABSTRACT There is widespread evidence that individuals select information that supports their convictions and worldviews. This behavior yields the formation of echo chambers – environments in which an individual’s own political beliefs are repeated and amplified and dissenting opinions are screened out. Recent research demonstrates that social networking sites such as Facebook or Twitter can facilitate this selection into homogenous networks. Using data from a representative nation-wide online survey, we consider the degree to which respondents’ social media networks resemble virtual echo chambers. We then analyze the effect of these social media echo chambers on satisfaction with democracy among Democrats and Republicans in the aftermath of the 2016 US elections. Our findings reveal that virtual echo chambers boost democratic satisfaction among Republicans but they do not have an effect on system support by self-identified Democrats. Our paper therefore adds to a growing literature linking online behaviors to mass attitudes about politics.

Non-epistemic Values and Concerns about Evolutionary Mindsets in Conservation Policy

This short article offers reflections on an approach to environmental policy and land management forwarded by Peter Kareiva and Emma Fuller. Their approach both mimics evolution in its structure and seeks to manage for evolution in application. They argue this approach is a novel perspective on policy that is more adaptive and flexible in setting realistic conservation goals and objectives. While we agree that their approach is a novel starting point for discussion of ecosystem resilience and adaptive management, we argue that they do not offer the required framework of guiding principles, or—more importantly—a set of values on which to base this particular environmental policy and management approach. We analyze the main driver behind Kareiva and Fullers article (an evolutionary perspective in regards to policy) with respect to non-epistemic values and outline key questions that will be important to inform environmental and conservation research, efforts, and policy.