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A hierarchical bayesian analysis of parasite prevalence and sociocultural outcomes: The role of structural racism and sanitation infrastructure
Author(s) -
Ross Cody T.,
Winterhalder Bruce
Publication year - 2015
Publication title -
american journal of human biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.559
H-Index - 81
eISSN - 1520-6300
pISSN - 1042-0533
DOI - 10.1002/ajhb.22757
Subject(s) - sociocultural evolution , sanitation , racism , biosocial theory , environmental health , geography , sociology , medicine , psychology , anthropology , social psychology , gender studies , personality , pathology
Objectives We conduct a revaluation of the Thornhill and Fincher research project on parasites using finely‐resolved geographic data on parasite prevalence, individual‐level sociocultural data, and multilevel Bayesian modeling. In contrast to the evolutionary psychological mechanisms linking parasites to human behavior and cultural characteristics proposed by Thornhill and Fincher, we offer an alternative hypothesis that structural racism and differential access to sanitation systems drive both variation in parasite prevalence and differential behaviors and cultural characteristics. Methods We adopt a Bayesian framework to estimate parasite prevalence rates in 51 districts in eight Latin American countries using the disease status of 170,220 individuals tested for infection with the intestinal roundworm Ascaris lumbricoides (Hürlimann et al., [[Hürlimann E, 2011]]: PLoS Negl Trop Dis 5:e1404). We then use district‐level estimates of parasite prevalence and individual‐level social data from 5,558 individuals in the same 51 districts (Latinobarómetro, 2008) to assess claims of causal associations between parasite prevalence and sociocultural characteristics. Results We find, contrary to Thornhill and Fincher, that parasite prevalence is positively associated with preferences for democracy, negatively associated with preferences for collectivism, and not associated with violent crime rates or gender inequality. A positive association between parasite prevalence and religiosity, as in Fincher and Thornhill ([Fincher CL, 2012]: Behav Brain Sci 35:61–79), and a negative association between parasite prevalence and achieved education, as predicted by Eppig et al. ([Eppig C, 2010]: Proc R S B: Biol Sci 277:3801–3808), become negative and unreliable when reasonable controls are included in the model. We find support for all predictions derived from our hypothesis linking structural racism to both parasite prevalence and cultural outcomes. Conclusions We conclude that best practices in biocultural modeling require examining more than one hypothesis, retaining individual‐level data and its associated variance whenever possible, and adopting multilevel techniques suited to the structuring of the data. Am. J. Hum. Biol. 28:74–89, 2016. © 2015 Wiley Periodicals, Inc.