Daniel J. Hruschka

Detecting Regular Sound Changes in Linguistics as Events of Concerted Evolution

Summary Background Concerted evolution is normally used to describe parallel changes at different sites in a genome, but it is also observed in languages where a specific phoneme changes to the same other phoneme in many words in the lexicon—a phenomenon known as regular sound change. We develop a general statistical model that can detect concerted changes in aligned sequence data and apply it to study regular sound changes in the Turkic language family. Results Linguistic evolution, unlike the genetic substitutional process, is dominated by events of concerted evolutionary change. Our model identified more than 70 historical events of regular sound change that occurred throughout the evolution of the Turkic language family, while simultaneously inferring a dated phylogenetic tree. Including regular sound changes yielded an approximately 4-fold improvement in the characterization of linguistic change over a simpler model of sporadic change, improved phylogenetic inference, and returned more reliable and plausible dates for events on the phylogenies. The historical timings of the concerted changes closely follow a Poisson process model, and the sound transition networks derived from our model mirror linguistic expectations. Conclusions We demonstrate that a model with no prior knowledge of complex concerted or regular changes can nevertheless infer the historical timings and genealogical placements of events of concerted change from the signals left in contemporary data. Our model can be applied wherever discrete elements—such as genes, words, cultural trends, technologies, or morphological traits—can change in parallel within an organism or other evolving group.

Redefine Statistical Significance

We propose to change the default P-value threshold for statistical significance from 0.05 to 0.005 for claims of new discoveries.

Nepali Concepts of Psychological Trauma: The Role of Idioms of Distress, Ethnopsychology and Ethnophysiology in Alleviating Suffering and Preventing Stigma

In the aftermath of a decade-long Maoist civil war in Nepal and the recent relocation of thousands of Bhutanese refugees from Nepal to Western countries, there has been rapid growth of mental health and psychosocial support programs, including posttraumatic stress disorder treatment, for Nepalis and ethnic Nepali Bhutanese. This medical anthropology study describes the process of identifying Nepali idioms of distress and local ethnopsychology and ethnophysiology models that promote effective communication about psychological trauma in a manner that minimizes stigma for service users. Psychological trauma is shown to be a multifaceted concept that has no single linguistic corollary in the Nepali study population. Respondents articulated different categories of psychological trauma idioms in relation to impact on the heart-mind, brain-mind, body, spirit, and social status, with differences in perceived types of traumatic events, symptom sets, emotion clusters and vulnerability. Trauma survivors felt blamed for experiencing negative events, which were seen as karma transmitting past life sins or family member sins into personal loss. Some families were reluctant to seek care for psychological trauma because of the stigma of revealing this bad karma. In addition, idioms related to brain-mind dysfunction contributed to stigma, while heart-mind distress was a socially acceptable reason for seeking treatment. Different categories of trauma idioms support the need for multidisciplinary treatment with multiple points of service entry.

Political violence and mental health in Nepal: prospective study.

BACKGROUND Post-conflict mental health studies in low-income countries have lacked pre-conflict data to evaluate changes in psychiatric morbidity resulting from political violence. AIMS This prospective study compares mental health before and after exposure to direct political violence during the Peoples War in Nepal. METHOD An adult cohort completed the Beck Depression Inventory and Beck Anxiety Inventory in 2000 prior to conflict violence in their community and in 2007 after the war. RESULTS Of the original 316 participants, 298 (94%) participated in the post-conflict assessment. Depression increased from 30.9 to 40.6%. Anxiety increased from 26.2 to 47.7%. Post-conflict post-traumatic stress disorder (PTSD) was 14.1%. Controlling for ageing, the depression increase was not significant. The anxiety increase showed a dose-response association with conflict exposure when controlling for ageing and daily stressors. No demographic group displayed unique vulnerability or resilience to the effects of conflict exposure. CONCLUSIONS Conflict exposure should be considered in the context of other types of psychiatric risk factors. Conflict exposure predicted increases in anxiety whereas socioeconomic factors and non-conflict stressful life events were the major predictors of depression. Research and interventions in post-conflict settings therefore should consider differential trajectories for depression v. anxiety and the importance of addressing chronic social problems ranging from poverty to gender and ethnic/caste discrimination.

Association of antenatal care with facility delivery and perinatal survival – a population-based study in Bangladesh

BackgroundAntenatal Care (ANC) during pregnancy can play an important role in the uptake of evidence-based services vital to the health of women and their infants. Studies report positive effects of ANC on use of facility-based delivery and perinatal mortality. However, most existing studies are limited to cross-sectional surveys with long recall periods, and generally do not include population-based samples.MethodsThis study was conducted within the Health and Demographic Surveillance System (HDSS) of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) in Matlab, Bangladesh. The HDSS area is divided into an icddr,b service area (SA) where women and children receive care from icddr,b health facilities, and a government SA where people receive care from government facilities. In 2007, a new Maternal, Neonatal, and Child Health (MNCH) program was initiated in the icddr,b SA that strengthened the ongoing maternal and child health services including ANC. We estimated the association of ANC with facility delivery and perinatal mortality using prospectively collected data from 2005 to 2009. Using a before-after study design, we also determined the role of ANC services on reduction of perinatal mortality between the periods before (2005 – 2006) and after (2008–2009) implementation of the MNCH program.ResultsAntenatal care visits were associated with increased facility-based delivery in the icddr,b and government SAs. In the icddr,b SA, the adjusted odds of perinatal mortality was about 2-times higher (odds ratio (OR) 1.91; 95% confidence intervals (CI): 1.50, 2.42) among women who received ≤1 ANC compared to women who received ≥3 ANC visits. No such association was observed in the government SA. Controlling for ANC visits substantially reduced the observed effect of the intervention on perinatal mortality (OR 0.64; 95% CI: 0.52, 0.78) to non-significance (OR 0.81; 95% CI: 0.65, 1.01), when comparing cohorts before and after the MNCH program initiation (Sobel test of mediation P < 0.001).ConclusionsANC visits are associated with increased uptake of facility-based delivery and improved perinatal survival in the icddr,b SA. Further testing of the icddr,b approach to simultaneously improving quality of ANC and facility delivery care is needed in the existing health system in Bangladesh and in other low-income countries to maximize health benefits to mothers and newborns.

When There Is More than One Answer Key: Cultural Theories of Postpartum Hemorrhage in Matlab, Bangladesh

Individuals can acquire cultural knowledge from many sources, including personal experience, informal learning, and schooling. Identifying these distinct source models and describing personal variation in their use present ongoing theoretical and methodological challenges. Three questions are of particular importance: (1) how to determine if there is more than one cultural model, (2) how to characterize the differences between models, and (3) how to assess the degree to which individuals draw from these different models. This article addresses these questions by analyzing the theories endorsed by women and their maternal care providers about the causes, signs, and treatments of postpartum hemorrhage in rural Bangladesh. Two cultural models are identified, each associated with traditional birth attendants or professionally trained “skilled” birth attendants. More broadly, the article discusses the statistical issues involved in determining the existence of multiple cultural models in a population.

Shared Norms and Their Explanation for the Social Clustering of Obesity

OBJECTIVES We aimed to test the hypothesized role of shared body size norms in the social contagion of body size and obesity. METHODS Using data collected in 2009 from 101 women and 812 of their social ties in Phoenix, Arizona, we assessed the indirect effect of social norms on shared body mass index (BMI) measured in 3 different ways. RESULTS We confirmed Christakis and Fowlers basic finding that BMI and obesity do indeed cluster socially, but we found that body size norms accounted for only a small portion of this effect (at most 20%) and only via 1 of the 3 pathways. CONCLUSIONS If shared social norms play only a minor role in the social contagion of obesity, interventions targeted at changing ideas about appropriate BMIs or body sizes may be less useful than those working more directly with behaviors, for example, by changing eating habits or transforming opportunities for and constraints on dietary intake.

Building social cognitive models of language change

Studies of language change have begun to contribute to answering several pressing questions in cognitive sciences, including the origins of human language capacity, the social construction of cognition and the mechanisms underlying culture change in general. Here, we describe recent advances within a new emerging framework for the study of language change, one that models such change as an evolutionary process among competing linguistic variants. We argue that a crucial and unifying element of this framework is the use of probabilistic, data-driven models both to infer change and to compare competing claims about social and cognitive influences on language change.

Distribution of distress in post-socialist Mongolia: a cultural epidemiology of yadargaa

This study discusses quality of life in post-socialist Mongolia. Yadargaa, a fatigue-related illness in traditional Mongolian medicine, results from lifestyle imbalance. We examine the distribution of yadargaa and its association to socioeconomic changes under capitalism. Ethnographic interviews concerning yadargaa were conducted with health professionals, yadargaa patients, and laypersons. Epidemiological methods were used to identify risk groups, to estimate the point prevalence, and to assess the distribution of meanings and interpretations of yadargaa. The epidemiological sample included 194 individuals, half urban and half rural. Nearly half of the epidemiological sample suffered from yadargaa (49%). These yadargaa sufferers felt that they benefited less than non-yadargaa subjects from the current socioeconomic changes. Among these, perceived change in employment opportunities was one of the best predictors of yadargaa. Additionally, yadargaa sufferers were predominantly women, the elderly, and urban residents. Yadargaa varies greatly in presentation; Western psychiatric categories are only able to explain half of yadargaa cases. In conclusion, yadargaa strongly associates with disenfranchised groups in the capitalist economy. As a culturally constructed indicator of quality of life, yadargaa is a window into the lives of women and men in post-socialist Mongolia.

Institutions, parasites and the persistence of in-group preferences.

Much research has established reliable cross-population differences in motivations to invest in one’s in-group. We compare two current historical-evolutionary hypotheses for this variation based on (1) effective large-scale institutions and (2) pathogen threats by analyzing cross-national differences (N = 122) in in-group preferences measured in three ways. We find that the effectiveness of government institutions correlates with favoring in-group members, even when controlling for pathogen stress and world region, assessing reverse causality, and providing a check on endogeneity with an instrumental variable analysis. Conversely, pathogen stress shows inconsistent associations with in-group favoritism when controlling for government effectiveness. Moreover, pathogen stress shows little to no association with in-group favoritism within major world regions whereas government effectiveness does. These results suggest that variation in in-group preferences across contemporary nation-states is more consistent with a generalized response to institutions that meet basic needs rather than an evolved response dedicated to pathogens.