Browsing by Subject "Social learning"

The study of culture in wild animals has received wide theoretical and empirical attention, providing preliminary evidence of at least rudimentary culture across a broad range of taxa. However, the majority of previous studies of animal cultural behavior have focused on demonstrating the existence of behavioral variants across study sites, armed only with an assumption that ecological and genetic alternatives are unlikely to sufficiently explain observed geographic variation in behavior. Moreover, previous studies have reported the presence of behavioral variation at the level of the population, without first confirming the presence of such variation in individual repertoires, which could create artificial patterns within or between populations.

Using more rigorous methods than previous studies, I examined rarely tested alternatives to field-based claims of cultural repertoire variation based on ecological heterogeneity and genetic variation. This dissertation relies on a natural experiment to compare two wild orangutan populations. Sungai Lading, a previously unstudied, high-density population of wild Pongo pygmaeus wurmbii, was compared to Tuanan, a P.p.wurmbii population separated from Sungai Lading by an impassable river barrier, but ranging in a broadly similar habitat. Preliminary genetics results indicate that at least some individuals from both sites cluster in the same mitochondrial subclade and that low levels of gene flow must have occurred between the two sites. Even after applying rigorous controls for variation in sampling intensity for individual orangutans, several differences in innovative behaviors exhibited at each site were identified, many of which occurred in the nesting context.

The orangutan is a model taxon for such an investigation, because wild populations exhibit a wide range of sociality, which has been linked to opportunities for social learning. Comparisons between the Tuanan and Sungai Lading populations indicated that cultural variants observed at only one site clustered significantly by population, although only dietary differences were unique at both sites. Orangutans at Sungai Lading maintain significantly lower rates of female-female association and lower individual repertoire sizes of putative cultural variants, a result that is consistent with the possibility that the orangutans of Sungai Lading may have reduced opportunities for social learning as a result of severe population compression, which could constrain opportunities for cultural transmission of key innovative behaviors.

From a broader perspective, the patterns revealed in this study strongly suggest that the last common ancestor of Homo and Pongo shared culturally modified behavior. They further suggest that the extent of cumulative cultural behavior in humans may surpass that of orangutans as a result of lost opportunities for social transmission, owing to varying degrees of limited association among group members.

The innovation and diffusion of new technologies is one of the central concerns of economics. New inventions or technological combinations do not spring fully formed into the world; as firms encounter and learn about new technologies they experiment, refine, and learn about them, improving productivity (and sometimes earning economic rents). Understanding the processes by which firms learn, and how these processes interact with regulations, is fundamental to understanding the emergence of new technologies, their contribution to growth, and the interaction of innovation and regulation.

This dissertation addresses how firms learn and respond to regulations in the context of emerging technologies. Within this framework, I address several questions. When production inputs are socially controversial, do firms respond to disclosure laws by voluntarily constraining their inputs? Do these public disclosure laws facilitate knowledge transmission across firms, and if so, what are the implications for public welfare - for instance, do the gains from trade outweigh any effects of reduced incentives for innovation? I study these questions in the context of hydraulic fracturing, though the results offer insight for more general settings. Panning out to a much broader view, I also explore how energy-related technologies - in both generation and consumption - diffuse across national boundaries over time, and whether innovation and diffusion of energy-efficient technologies has led to more or less energy-efficient economic growth.

In my first paper, I contribute to improved understanding of the conditions in which information-based regulations, which are increasingly common in multiple policy domains, decrease externalities such as environmental pollution. Specifically, I test whether information disclosure regulations applied to hydraulic fracturing chemicals caused firms to decrease their use of toxic inputs. Prior to these mandatory disclosure laws, some operators voluntarily disclosed fluid components for some or all of their wells. I compare the chemical mixtures used prior to the mandatory disclosure laws to those used after the laws took effect, using a difference-in-differences method motivated by the difference in timing of state-level disclosure laws. I use voluntary disclosures to measure the toxicity of fluids prior to mandated disclosure, and thus observe a composite effect of both full reporting and disclosure pressure. These effects likely have opposite signs; I employ several methods to tease them apart so that I can separately identify the effect of disclosure pressure. My analysis, which covers over 70,000 wells in seven states, suggests that state disclosure regulations resulted in a large and persistent decrease in the use of toxic and regulated chemicals in fracturing fluids. This is not the first paper to find that disclosure regulations can change firms' behavior, but it demonstrates such an effect in a setting in which consumer or market pressure is minimal or nonexistent: firms that produce undifferentiated products for an intermediate market, and disclosure policies that do not generate readily accessible or interpretable information.

The second paper tests whether disclosure laws facilitated the transmission of useful knowledge across companies. It is well established that economic agents learn about new technologies in part from other adopters, though even sophisticated firms may not take full advantage of social learning. With my co-authors, I examine whether firms took advantage of environmentally-focused disclosure laws to learn from competitors and improve productivity. We find evidence that they did: following mandatory disclosure we observe convergence in productivity per well, in production inputs, and strong evidence of a link between the two. To our knowledge this is the first study to examine this pathway for social learning in an emerging technology. This could also be interpreted as a form of technology diffusion facilitated by environmental regulation.

In my third paper, I address a broader scale of technology change, looking for evidence that improved technologies for energy generation and consumption have allowed less energy-intensive or pollution-intensive growth in developing countries. I analyze panel data on Gross Domestic Product (GDP) and national energy consumption to look for evidence of technology "leapfrogging" (i.e., decreased intensity of energy consumption for a given level of economic growth). I combine 1960-2014 data on energy consumption from the International Energy Agency with historical data that extends back to 1861 for several countries on energy consumption and fuel source, as well as GDP. I compare countries at the same income level and test whether energy consumption and energy intensity are different for today's less-developed countries compared to today's industrialized countries when they had similar income levels. Compared to prior analysis, my much longer time series allows me to test for leapfrogging over a scale appropriate to the pace of widespread technological change.

Abstract

Risky foraging is a male reproductive tactic in most polygynous mammals. It is speculated to result from intense intra-sexual reproductive competition. Consequently this behavior has been speculated to increase a male's reproductive competitiveness. However, individual males may differ in their propensity to take foraging risks.

We therefore conducted a study on crop raiding behavior (a risky foraging strategy) in African elephants from the greater Amboseli ecosystem, in southern Kenya. We specifically examined the population sizes, gender and patterns of raiding elephants and investigated the effect of crop-raiding and genetic heterozygosity on male body size. We also examined the influence of age and genetic relatedness on observed patterns of association. Finally, we examined the role of life history milestones, association patterns and social structure on the acquisition of crop raiding behavior among wild free ranging male African elephants. With regard to the influence of association patterns on crop raiding behavior, we were specifically interested in understanding the mechanisms by which social learning might occur among male elephants.

Our results showed that 241elephants from different populations in the ecosystem converged to raid farms. Approximately 35% of raiders were from Amboseli National Park, and the rest were other populations in the ecosystem. We observed only post-pubertal males but not females to raid. About one third of post-pubertal males from the Amboseli population were raiders. We found evidence of habitual raiding by some individuals. Crop raiding predicted post-pubertal male size, with raiders being larger than non-raiders. This result suggests that taking risks pays off for males. Our results also showed that other variables known to influence growth like genetic heterozygosity had no effect on size-for-age in male elephants, because low-heterozygosity males were rare. The probability that an individual male is a crop raider was greater for older individuals than young males. The probability that a male is a raider was greater when his two closest associates were raiders versus when they were not raiders and when a male's second closest associate was older, versus when his second closest associate was of similar age or younger. These results suggest that increasing energetic demands associated with life history milestones and social learning play a significant role in the initiation of crop raiding behavior. Raiders did not cluster into separate social units from non-raiders, probably due to the nature of social learning exhibited by this species and due to the diffuse nature of male elephant social units.

These results have implications for understanding the evolution of risky foraging behavior in males, and for understanding the role of kin selection, dominance hierarchies and social learning in male elephant social systems. Results also have implications for understanding the spread of adaptive complex behavior in natural populations.