Within-Physician Differences in Patient Sharing Between Primary Care Physicians and Cardiologists Who Treat White and Black Patients With Heart Disease.

BACKGROUND: Black-White disparities in heart disease treatment may be attributable to differences in physician referral networks. We mapped physician networks for Medicare patients and examined within-physician Black-White differences in patient sharing between primary care physicians and cardiologists. METHODS AND RESULTS: Using Medicare fee-for-service files for 2016 to 2017, we identified a cohort of Black and White patients with heart disease and the primary care physicians and cardiologists treating them. To ensure the robustness of within-physician comparisons, we restricted the sample to regional health care markets (ie, hospital referral regions) with at least 10 physicians sharing ≥3 Black and White patients. We used claims to construct 2 race-specific physician network measures: degree (number of cardiologists with whom a primary care physician shares patients) and transitivity (network tightness). Measures were adjusted for Black-White differences in physician panel size and calculated for all settings (hospital and office) and for office settings only. Of 306 US hospital referral regions, 226 and 145 met study criteria for all settings and office setting analyses, respectively. Black patients had more cardiology encounters overall (6.9 versus 6.6; P<0.001) and with unique cardiologists (3.0 versus 2.6; P<0.001), but fewer office encounters (31.7% versus 41.1%; P<0.001). Primary care physicians shared Black patients with more cardiologists than White patients (mean differential degree 23.4 for all settings and 3.6 for office analyses; P<0.001 for both). Black patient-sharing networks were less tightly connected in all but office settings (mean differential transitivity -0.2 for all settings [P<0.001] and near 0 for office analyses [P=0.74]). CONCLUSIONS: Within-physician Black-White differences in patient sharing exist and may contribute to disparities in cardiac care.

Messaging Strategies for Mitigating COVID-19 Through Vaccination and Nonpharmaceutical Interventions.

With new coronavirus disease 2019 (COVID-19) vaccines authorized by the U.S. Food and Drug Administration and likely more to come, the (extraordinarily complex) logistics of deploying them have gotten underway. Public health officials across the country face a daunting task: convincing the majority of individuals to queue up for shots while also maintaining a steady supply of doses and efficient appointment sign-ups. The road ahead is still long and, even with increasing vaccination, will still require adherence with other effective public health behaviors, such as mask-wearing. This article addresses the importance of effectively matching the message, the audience, and the sender for messages to promote uptake of vaccination and of such behaviors as mask-wearing. It offers suggestions about how to leverage such factors as variations in risk perception and variation among U.S. subcultures regarding tendencies to follow rules and to act for the good of the group. The authors also review evidence that suggests health messages should engage directly with misinformation to refute it.

Belief correlations with parental vaccine hesitancy: Results from a national survey.

We conducted a nationally representative survey of parents' beliefs and self-reported behaviors regarding childhood vaccinations. Using Bayesian selection among multivariate models, we found that beliefs, even those without any vaccine or health content, predicted vaccine-hesitant behaviors better than demographics, social network effects, or scientific reasoning. The multivariate structure of beliefs combined many types of ideation that included concerns about both conspiracies and side effects. Although they are not strongly related to vaccine-hesitant behavior, demographics were key predictors of beliefs. Our results support some of the previously proposed pro-vaccination messaging strategies and suggest some new strategies not previously considered.

Realizamos una encuesta nacionalmente representativa sobre las creencias y comportamientos autodeclarados por los padres con relación a la vacunación infantil. Usando selección bayesiana entre modelos multivariados, encontramos que las creencias, aun aquellas sin ningún contenido sobre vacunas o salud, predijeron comportamientos indecisos sobre la vacuna mejor que las características demográficas, los efectos de las redes sociales o el razonamiento científico. La estructura multivariada de las creencias combinó muchos tipos de ideación que incluyó preocupaciones tanto sobre conspiraciones como efectos secundarios. Aunque no están relacionados fuertemente con los comportamientos de indecisión, las características demográficas fueron predictores centrales de las creencias. Nuestros resultados apoyan algunas de las estrategias de mensajes pro­vacunación propuestas previamente y sugieren algunas nuevas estrategias no consideradas anteriormente. [vacunación, encuesta, cultura acumulativa, bayesiana].

Shared cultural ancestry predicts the global diffusion of democracy.

Understanding global variation in democratic outcomes is critical to efforts to promote and sustain democracy today. Here, we use data on the democratic status of 221 modern and historical nations stretching back up to 200 years to show that, particularly over the last 50 years, nations with shared linguistic and, more recently, religious ancestry have more similar democratic outcomes. We also find evidence that for most of the last 50 years the democratic trajectory of a nation can be predicted by the democratic status of its linguistic and, less clearly, religious relatives, years and even decades earlier. These results are broadly consistent across three democracy indicators (Polity 5, Vanhanen's Index of Democracy, and Freedom in the World) and are not explained by geographical proximity or current shared language or religion. Our findings suggest that deep cultural ancestry remains an important force shaping the fortunes of modern nations, at least in part because democratic norms, institutions, and the factors that support them are more likely to diffuse between close cultural relatives.

Association among trust in health care providers, friends, and family, and vaccine hesitancy.

A health care provider's vaccination recommendation is one of the most important factors influencing parents' decisions about whether to vaccinate their children. Unfortunately, vaccine hesitancy is associated with mistrust of health care providers and the medical system. We conducted a survey of 2440 adults through the RAND American Life Panel in 2019. Respondents were asked to rate their trust in pediatricians, OB/GYNs, doulas, midwives, lactation consultants, friends and family for information about childhood vaccines. Respondents were also asked about willingness to vaccinate a hypothetical child as a measure of vaccine hesitancy. We used principal component analysis to characterize variance in responses on trust items and logistic regression to model the relationship between trust and vaccine hesitancy. Vaccine hesitancy was associated with: (1) lower overall trust; (2) reduced trust in OB/GYNs and pediatricians and greater trust in doulas, midwives, and lactation consultants; and (3) greater trust in friends and family.

Comparing covariation among vaccine hesitancy and broader beliefs within Twitter and survey data.

Over the past decade, the percentage of adults in the United States who use some form of social media has roughly doubled, increasing from 36 percent in early 2009 to 72 percent in 2019. There has been a corresponding increase in research aimed at understanding opinions and beliefs that are expressed online. However, the generalizability of findings from social media research is a subject of ongoing debate. Social media platforms are conduits of both information and misinformation about vaccines and vaccine hesitancy. Our research objective was to examine whether we can draw similar conclusions from Twitter and national survey data about the relationship between vaccine hesitancy and a broader set of beliefs. In 2018 we conducted a nationally representative survey of parents in the United States informed by a literature review to ask their views on a range of topics, including vaccine side effects, conspiracy theories, and understanding of science. We developed a set of keyword-based queries corresponding to each of the belief items from the survey and pulled matching tweets from 2017. We performed the data pull of the most recent full year of data in 2018. Our primary measures of belief covariation were the loadings and scores of the first principal components obtained using principal component analysis (PCA) from the two sources. We found that, after using manually coded weblinks in tweets to infer stance, there was good qualitative agreement between the first principal component loadings and scores using survey and Twitter data. This held true after we took the additional processing step of resampling the Twitter data based on the number of topics that an individual tweeted about, as a means of correcting for differential representation for elicited (survey) vs. volunteered (Twitter) beliefs. Overall, the results show that analyses using Twitter data may be generalizable in certain contexts, such as assessing belief covariation.

The cultural foundations of modern democracies.

National democracy is a rare thing in human history and its stability has long been tied to the cultural values of citizens. Yet it has not been established whether changing cultural values made modern democracy possible or whether those values were a response to democratic institutions. Here we combine longitudinal data and cohort information of nearly 500,000 individuals from 109 nations to track the co-evolution of democratic values and institutions over the last century. We find that cultural values of openness towards diversity predict a shift towards democracy and that nations with low institutional confidence are prone to political instability. In addition, the presence of democratic institutions did not predict any substantive changes in the measured cultural values. These results hold accounting for other factors, including gross domestic product per capita and non-independence between nations due to shared cultural ancestry. Cultural values lead to, rather than follow, the emergence of democracy. This indicates that current stable democracies will be under threat, should cultural values of openness to diversity and institutional confidence substantially decline.

Shared Cultural History as a Predictor of Political and Economic Changes among Nation States.

Political and economic risks arise from social phenomena that spread within and across countries. Regime changes, protest movements, and stock market and default shocks can have ramifications across the globe. Quantitative models have made great strides at predicting these events in recent decades but incorporate few explicitly measured cultural variables. However, in recent years cultural evolutionary theory has emerged as a major paradigm to understand the inheritance and diffusion of human cultural variation. Here, we combine these two strands of research by proposing that measures of socio-linguistic affiliation derived from language phylogenies track variation in cultural norms that influence how political and economic changes diffuse across the globe. First, we show that changes over time in a country's democratic or autocratic character correlate with simultaneous changes among their socio-linguistic affiliations more than with changes of spatially proximate countries. Second, we find that models of changes in sovereign default status favor including socio-linguistic affiliations in addition to spatial data. These findings suggest that better measurement of cultural networks could be profoundly useful to policy makers who wish to diversify commercial, social, and other forms of investment across political and economic risks on an international scale.

Methods for inferring health-related social networks among coworkers from online communication patterns.

Studies of social networks, mapped using self-reported contacts, have demonstrated the strong influence of social connections on the propensity for individuals to adopt or maintain healthy behaviors and on their likelihood to adopt health risks such as obesity. Social network analysis may prove useful for businesses and organizations that wish to improve the health of their populations by identifying key network positions. Health traits have been shown to correlate across friendship ties, but evaluating network effects in large coworker populations presents the challenge of obtaining sufficiently comprehensive network data. The purpose of this study was to evaluate methods for using online communication data to generate comprehensive network maps that reproduce the health-associated properties of an offline social network. In this study, we examined three techniques for inferring social relationships from email traffic data in an employee population using thresholds based on: (1) the absolute number of emails exchanged, (2) logistic regression probability of an offline relationship, and (3) the highest ranked email exchange partners. As a model of the offline social network in the same population, a network map was created using social ties reported in a survey instrument. The email networks were evaluated based on the proportion of survey ties captured, comparisons of common network metrics, and autocorrelation of body mass index (BMI) across social ties. Results demonstrated that logistic regression predicted the greatest proportion of offline social ties, thresholding on number of emails exchanged produced the best match to offline network metrics, and ranked email partners demonstrated the strongest autocorrelation of BMI. Since each method had unique strengths, researchers should choose a method based on the aspects of offline behavior of interest. Ranked email partners may be particularly useful for purposes related to health traits in a social network.

The recognition signal hypothesis for the adaptive evolution of religion : a phylogenetic test with Christian denominations.

Recent research on the evolution of religion has focused on whether religion is an unselected by-product of evolutionary processes or if it is instead an adaptation by natural selection. Adaptive hypotheses for religion include direct fitness benefits from improved health and indirect fitness benefits mediated by costly signals and/or cultural group selection. Herein, I propose that religious denominations achieve indirect fitness gains for members through the use of ecologically arbitrary beliefs, rituals, and moral rules that function as recognition markers of cultural inheritance analogous to kin and species recognition of genetic inheritance in biology. This recognition signal hypotheses could act in concert with either costly signaling or cultural group selection to produce evolutionarily altruistic behaviors within denominations. Using a cultural phylogenetic analysis, I show that a large set of religious behaviors among extant Christian denominations supports the prediction of the recognition signal hypothesis that characters change more frequently near historical schisms. By incorporating demographic data into the model, I show that more-distinctive denominations, as measured through dissimilar characteristics, appear to be protected from intrusion by nonmembers in mixed-denomination households, and that they may be experiencing greater biological growth of their populations even in the present day.

Evolutionary disequilibrium and activity period in primates: a bayesian phylogenetic approach.

Activity period plays a central role in studies of primate origins and adaptations, yet fundamental questions remain concerning the evolutionary history of primate activity period. Lemurs are of particular interest because they display marked variation in activity period, with some species exhibiting completely nocturnal or diurnal lifestyles, and others distributing activity throughout the 24-h cycle (i.e., cathemerality). Some lines of evidence suggest that cathemerality in lemurs is a recent and transient evolutionary state (i.e., the evolutionary disequilibrium hypothesis), while other studies indicate that cathemerality is a stable evolutionary strategy with a more ancient history. Debate also surrounds activity period in early primate evolution, with some recent studies casting doubt on the traditional hypothesis that basal primates were nocturnal. Here, we used Bayesian phylogenetic methods to reconstruct activity period at key points in primate evolution. Counter to the evolutionary disequilibrium hypothesis, the most recent common ancestor of Eulemur was reconstructed as cathemeral at ∼9-13 million years ago, indicating that cathemerality in lemurs is a stable evolutionary strategy. We found strong evidence favoring a nocturnal ancestor for all primates, strepsirrhines and lemurs, which adds to previous findings based on parsimony by providing quantitative support for these reconstructions. Reconstructions for the haplorrhine ancestor were more equivocal, but diurnality was favored for simian primates. We discuss the implications of our models for the evolutionary disequilibrium hypothesis, and we identify avenues for future research that would provide new insights into the evolution of cathemerality in lemurs.

How does cognition evolve? Phylogenetic comparative psychology.

Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly skillful at adapting methodologies to test multiple species. Meanwhile, evolutionary biologists have generated quantitative approaches to investigate the phylogenetic distribution and function of phenotypic traits, including cognition. In particular, phylogenetic methods can quantitatively (1) test whether specific cognitive abilities are correlated with life history (e.g., lifespan), morphology (e.g., brain size), or socio-ecological variables (e.g., social system), (2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species, and (3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species. Phylogenetic methods can also be used to guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (i.e., phylogenetic targeting). Here, we explain how an integration of comparative psychology and evolutionary biology will answer a host of questions regarding the phylogenetic distribution and history of cognitive traits, as well as the evolutionary processes that drove their evolution.

Variations in sexual behavior among capuchin monkeys function for conspecific mate recognition: a phylogenetic analysis and a new hypothesis for female proceptivity in tufted capuchins.

Researchers of capuchin monkeys have noted stereotyped body postures, facial expressions, and vocalizations that accompany copulations in this genus. Notable variations in these sexual behaviors are observed across capuchin species. Although several hypotheses exist to explain variation in the duration and vigor of sexual behaviors across species, there is no proposed explanation for variation in the forms of these behaviors. I hypothesized that the forms of sexual behaviors function as recognition signals of conspecific mates. Such signals are adaptive when F1 hybrids exhibit reduced fitness compared with nonhybrid offspring. Recent evidence from nonprimate taxa supports the existence of species recognition signals during mating. Using newly observed sexual behaviors for Cebus albifrons and a recent phylogeny of capuchins, I found significant support for a key prediction of the conspecific mate recognition hypothesis: evolutionary changes in sexual behaviors were associated with speciation. Given the resultant best model for evolution of sexual behaviors, I reconstructed the ancestral pattern of sexual behaviors for extant capuchin species (genera Cebus and Sapajus). This reconstruction suggests that the extreme female proceptivity of tufted capuchin monkeys may function to increase female reproductive choices in the context of sperm-limited males (genus Sapajus).

Testing for divergent transmission histories among cultural characters: a study using Bayesian phylogenetic methods and Iranian tribal textile data.

BACKGROUND: Archaeologists and anthropologists have long recognized that different cultural complexes may have distinct descent histories, but they have lacked analytical techniques capable of easily identifying such incongruence. Here, we show how bayesian phylogenetic analysis can be used to identify incongruent cultural histories. We employ the approach to investigate Iranian tribal textile traditions. METHODS: We used bayes factor comparisons in a phylogenetic framework to test two models of cultural evolution: the hierarchically integrated system hypothesis and the multiple coherent units hypothesis. In the hierarchically integrated system hypothesis, a core tradition of characters evolves through descent with modification and characters peripheral to the core are exchanged among contemporaneous populations. In the multiple coherent units hypothesis, a core tradition does not exist. Rather, there are several cultural units consisting of sets of characters that have different histories of descent. RESULTS: For the Iranian textiles, the bayesian phylogenetic analyses supported the multiple coherent units hypothesis over the hierarchically integrated system hypothesis. Our analyses suggest that pile-weave designs represent a distinct cultural unit that has a different phylogenetic history compared to other textile characters. CONCLUSIONS: The results from the Iranian textiles are consistent with the available ethnographic evidence, which suggests that the commercial rug market has influenced pile-rug designs but not the techniques or designs incorporated in the other textiles produced by the tribes. We anticipate that bayesian phylogenetic tests for inferring cultural units will be of great value for researchers interested in studying the evolution of cultural traits including language, behavior, and material culture.

Novelty-seeking DRD4 polymorphisms are associated with human migration distance out-of-Africa after controlling for neutral population gene structure.

Numerous lines of evidence suggest that Homo sapiens evolved as a distinct species in Africa by 150,000 years before the present (BP) and began major migrations out-of-Africa ∼50,000 BP. By 20,000 BP, our species had effectively colonized the entire Old World, and by 12,000 BP H. sapiens had a global distribution. We propose that this rapid migration into new habitats selected for individuals with low reactivity to novel stressors. Certain dopamine receptor D4 (DRD4) polymorphisms are associated with low neuronal reactivity and increased exploratory behavior, novelty seeking, and risk taking, collectively considered novelty-seeking trait (NS). One previous report (Chen et al.: Evol Hum Behav 20 (1999) 309-324) demonstrated a correlation between migratory distance and the seven-repeat (7R) VNTR DRD4 allele at exon 3 for human populations. This study, however, failed to account for neutral genetic processes (drift and admixture) that might create such a correlation in the absence of natural selection. Furthermore, additional loci surrounding DRD4 are now recognized to influence NS. Herein we account for neutral genetic structure by modeling the nonindependence of neutral allele frequencies between human populations. We retest the DRD4 exon 3 alleles, and also test two other loci near DRD4 that are associated with NS. We conclude there is an association between migratory distance and DRD4 exon 3 2R and 7R alleles that cannot be accounted for by neutral genetic processes alone.

Primate extinction risk and historical patterns of speciation and extinction in relation to body mass.

Body mass is thought to influence diversification rates, but previous studies have produced ambiguous results. We investigated patterns of diversification across 100 trees obtained from a new Bayesian inference of primate phylogeny that sampled trees in proportion to their posterior probabilities. First, we used simulations to assess the validity of previous studies that used linear models to investigate the links between IUCN Red List status and body mass. These analyses support the use of linear models for ordinal ranked data on threat status, and phylogenetic generalized linear models revealed a significant positive correlation between current extinction risk and body mass across our tree block. We then investigated historical patterns of speciation and extinction rates using a recently developed maximum-likelihood method. Specifically, we predicted that body mass correlates positively with extinction rate because larger bodied organisms reproduce more slowly, and body mass correlates negatively with speciation rate because smaller bodied organisms are better able to partition niche space. We failed to find evidence that extinction rates covary with body mass across primate phylogeny. Similarly, the speciation rate was generally unrelated to body mass, except in some tests that indicated an increase in the speciation rate with increasing body mass. Importantly, we discovered that our data violated a key assumption of sample randomness with respect to body mass. After correcting for this bias, we found no association between diversification rates and mass.

Can Traditions Emerge from the Interaction of Stimulus Enhancement and Reinforcement Learning? An Experimental Model.

The study of social learning in captivity and behavioral traditions in the wild are two burgeoning areas of research, but few empirical studies have tested how learning mechanisms produce emergent patterns of tradition. Studies have examined how social learning mechanisms that are cognitively complex and possessed by few species, such as imitation, result in traditional patterns, yet traditional patterns are also exhibited by species that may not possess such mechanisms. We propose an explicit model of how stimulus enhancement and reinforcement learning could interact to produce traditions. We tested the model experimentally with tufted capuchin monkeys (Cebus apella), which exhibit traditions in the wild but have rarely demonstrated imitative abilities in captive experiments. Monkeys showed both stimulus enhancement learning and a habitual bias to perform whichever behavior first obtained them a reward. These results support our model that simple social learning mechanisms combined with reinforcement can result in traditional patterns of behavior.

Social enhancement can create adaptive, arbitrary and maladaptive cultural traditions.

Many animals are known to learn socially, i.e. they are able to acquire new behaviours by using information from other individuals. Researchers distinguish between a number of different social-learning mechanisms such as imitation and social enhancement. Social enhancement is a simple form of social learning that is among the most widespread in animals. However, unlike imitation, it is debated whether social enhancement can create cultural traditions. Based on a recent study on capuchin monkeys, we developed an agent-based model to test the hypotheses that (i) social enhancement can create and maintain stable traditions and (ii) social enhancement can create cultural conformity. Our results supported both hypotheses. A key factor that led to the creation of cultural conformity and traditions was the repeated interaction of individual reinforcement and social enhancement learning. This result emphasizes that the emergence of cultural conformity does not necessarily require cognitively complex mechanisms such as 'copying the majority' or group norms. In addition, we observed that social enhancement can create learning dynamics similar to a 'copy when uncertain' learning strategy. Results from additional analyses also point to situations that should favour the evolution of learning mechanisms more sophisticated than social enhancement.

Successive radiations, not stasis, in the South American primate fauna.

The earliest Neotropical primate fossils complete enough for taxonomic assessment, Dolichocebus, Tremacebus, and Chilecebus, date to approximately 20 Ma. These have been interpreted as either closely related to extant forms or as extinct stem lineages. The former hypothesis of morphological stasis requires most living platyrrhine genera to have diverged before 20 Ma. To test this hypothesis, we collected new complete mitochondrial genomes from Aotus lemurinus, Saimiri sciureus, Saguinus oedipus, Ateles belzebuth, and Callicebus donacophilus. We combined these with published sequences from Cebus albifrons and other primates to infer the mitochondrial phylogeny. We found support for a cebid/atelid clade to the exclusion of the pitheciids. Then, using Bayesian methods and well-supported fossil calibration constraints, we estimated that the platyrrhine most recent common ancestor (MRCA) dates to 19.5 Ma, with all major lineages diverging by 14.3 Ma. Next, we estimated catarrhine divergence dates on the basis of platyrrhine divergence scenarios and found that only a platyrrhine MRCA less than 21 Ma is concordant with the catarrhine fossil record. Finally, we calculated that 33% more change in the rate of evolution is required for platyrrhine divergences consistent with the morphologic stasis hypothesis than for a more recent radiation. We conclude that Dolichocebus, Tremacebus, and Chilecebus are likely too old to be crown platyrrhines, suggesting they were part of an extinct early radiation. We note that the crown platyrrhine radiation was concomitant with the radiation of 2 South American xenarthran lineages and follows a global temperature peak and tectonic activity in the Andes.

Taxon combinations, parsimony analysis (PAUP*), and the taxonomy of the yellow-tailed woolly monkey, Lagothrix flavicauda.

The classifications of primates, in general, and platyrrhine primates, in particular, have been greatly revised subsequent to the rationale for taxonomic decisions shifting from one rooted in the biological species concept to one rooted solely in phylogenetic affiliations. Given the phylogenetic justification provided for revised taxonomies, the scientific validity of taxonomic distinctions can be rightly judged by the robusticity of the phylogenetic results supporting them. In this study, we empirically investigated taxonomic-sampling effects on a cladogram previously inferred from craniodental data for the woolly monkeys (Lagothrix). We conducted the study primarily through much greater sampling of species-level taxa (OTUs) after improving some character codings and under a variety of outgroup choices. The results indicate that alternative selections of species subsets from within genera produce various tree topologies. These results stand even after adjusting the character set and considering the potential role of interobserver disagreement. We conclude that specific taxon combinations, in this case, generic or species pairings, of the primary study group has a biasing effect in parsimony analysis, and that the cladistic rationale for resurrecting the Oreonax generic distinction for the yellow-tailed woolly monkey (Lagothrix flavicauda) is based on an artifact of idiosyncratic sampling within the study group below the genus level. Some recommendations to minimize the problem, which is prevalent in all cladistic analyses, are proposed.