Fincher & Thornhill's (F&T's) central hypothesis is that strong in-group norms were formed in part to foster parochial social alliances – including values for bonding families, castes, ethnicities, and religions – so as to enable cultural groups to adaptively respond to parasite stress. Applied to ancestral hominid environments, the story fits with evolutionary theory and the fragmentary data available on early hominid social formations and their geographical distributions. Applied to modern social formations, however, the arguments and inferences from data are problematic. There is also too precipitous a leap from correlation to cause, which is the distance that is the task of science to cover.
Thus, to say that “castes were formed” from differential response to parasite stress is to put the historical cart before the horse. Castes were initially formed to keep conquering Indo-European invaders from diluting power with “inferior” native peoples of South Asia. (The genetic affinity of Indians to Europeans is proportionate to caste rank, the upper castes being most similar to Europeans, whereas lower castes are more like other South Asians; Bamshad et al. Reference Bamshad, Kivisild, Watkins, Dixon, Ricker, Rao, Naidu, Prasad, Reddy, Rasanayagam, Papiha, Villems, Redd, Hammer, Nguyen, Carroll, Batzer and Jorder2001). The imposed conditions of substandard health and hygiene (relative to the conquerors) reinforced social separation through fear of contagion, where risk from biological contagion was readily confounded with social and mental contagion. Variations on this type of process, of course, marked the history of European colonialism as well (Stoler Reference Stoler2010).
Although ethnic exclusivity is probably as old as our species (Atran Reference Atran2001), in modern forms of nationalism it is more a social construction that stems in large part from the failed European political and social revolutions of 1848. These revolutions were fueled by ideologies preaching the emancipation of peoples and the dismantling of political and social boundaries. The lesson drawn by the victorious ruling elites to forestall future uprisings was that the “lower classes” must be made to feel themselves integral parts of exclusive nationalities steeped in common “blood,” but where rich and poor still had almost inescapably distinct derivations from the common national “essence” (Dowe Reference Dowe2001). These developments, again, reinforced the social and biological isolation of cultural groups and subgroups, including differential susceptibility and response to pathogens and parasite stress.
But it is with respect to the role of religion that the authors' arguments are most problematic. It is certainly plausible that “religious groups adopt their own distinct costly versions of supernatural beliefs in order to heighten costs of participation and distance themselves from out-groups” (target article, sect. 3.2, para. 3). Nevertheless, for at least the past three millennia or so, the most expansive and successful religions aimed to include as many genetic strangers as possible (Atran & Henrich Reference Atran and Henrich2010). Consider Christianity, the first truly universal religion, which still today has the largest group following on the planet. Originally attached to Jewish diaspora settlements throughout the Roman empire, it steadily gained a following of a few percentage points of the empire's population each year – especially among women, slaves, and other disadvantaged elements – until gaining a majority shortly before Emperor Constantine's conversion. Before Constantine's militarization of the faith in the fourth century, Christianity progressed mainly through costly, charitable acts of self-sacrifice, most notably in tending strangers with plague and other infectious diseases who were usually abandoned by their own kinfolk (Stark Reference Stark1997). The first true hospitals to care for the sick, including contagious lepers, were founded by Christians at Constantinople. Islam was militarized from the beginning, but realized its greatest expansion and flowering among non-Arab peoples (Berbers, Jews, Latins, Germans, Persians, Kurds, Turks, and so forth). With initial assistance from Christians, Islamic hospitals were tending those afflicted by infectious diseases by the beginning of the eighth century (Risse Reference Risse1999). Buddha also taught to tend the sick strangers, of whatever caste, so as to help eliminate all castes (largely a failure in India but very successful elsewhere). Pentacostalists and other Evangelical groups, as well as Muslim missionaries, are still converting millions in Asia, Africa, and the Americas through open-door charitable efforts (see Atran & Henrich Reference Atran and Henrich2010).
F&T claim that religiosity involves “an underlying mental mechanism” (sect. 3.2, para. 6) that encourages religious group similarity. This is misleading. There are no set principles or rules specific to religion, nor any adaptive religious complex that seems stable enough to undergo evolution by natural selection (Atran & Norenzayan Reference Atran and Norenzayan2004). Rather, religions involve a host of ordinary cognitive mechanisms (including those which produce fairy tales and supernaturals) whose distributions take on a characteristic religious aspect (in a “family resemblance” sort of way) in trying to deal with certain irresolvable but ineluctable aspects of the human condition (including “existential dilemmas” such as death, deception, catastrophe, and so forth). Moreover, in today's world, religions are as permeable as the transnational ideological -isms (actually, secular salvational monotheisms) that began to vie for domination of modern political life with the American and French Revolutions.
The inference that economic development “causes” religious decline and promotes democracy is also somewhat misleading. It is simply that institutionalized religions in the West were traditionally associated with older power structures. These have been largely replaced by secular political ideologies and parties, which continue to have “sacred” and transcendental (if not supernatural) aspects, whether attributed to Providence or Nature (Atran Reference Atran2010; Atran & Axelrod Reference Atran and Axelrod2008). The one consistent finding from political science is that the best predictor of democracy is not economic development per se, but the presence of a large and stable middle class. The initial rise of the American and European middle class was heavily religion-and-community based (de Tocqueville (Reference de Tocqueville1835/1984); Weber Reference Weber and Parsons1958). “Individualism,” which is a phenomenon largely associated with the demise of American community life in the later decades of the twentieth century (Putnam Reference Putnam2001), has become an analytic category chiefly because the country's major social analysts now recognize that much of the rest of world still has community-sharing traditions (“collectivists”). This is not because the rest of the world is more prone to parasite stress, and therefore more responsive to religion and less taken with democracy, but because modern forms of health care and hygiene, secular rights, and democratic governance, are all fairly new and still predominantly localized with the former colonial metropoles and their oldest former colonies.
Finally, even if parasite stress is significantly correlated with phenomena such as high religiosity or lack of democracy, that in no way informs us how religious or political systems are actually structured or modified under evolution. But, given the correlation data presented, parasite stress does merit further consideration as a possible selection factor in their persistence or hindrance.
Fincher & Thornhill's (F&T's) central hypothesis is that strong in-group norms were formed in part to foster parochial social alliances – including values for bonding families, castes, ethnicities, and religions – so as to enable cultural groups to adaptively respond to parasite stress. Applied to ancestral hominid environments, the story fits with evolutionary theory and the fragmentary data available on early hominid social formations and their geographical distributions. Applied to modern social formations, however, the arguments and inferences from data are problematic. There is also too precipitous a leap from correlation to cause, which is the distance that is the task of science to cover.
Thus, to say that “castes were formed” from differential response to parasite stress is to put the historical cart before the horse. Castes were initially formed to keep conquering Indo-European invaders from diluting power with “inferior” native peoples of South Asia. (The genetic affinity of Indians to Europeans is proportionate to caste rank, the upper castes being most similar to Europeans, whereas lower castes are more like other South Asians; Bamshad et al. Reference Bamshad, Kivisild, Watkins, Dixon, Ricker, Rao, Naidu, Prasad, Reddy, Rasanayagam, Papiha, Villems, Redd, Hammer, Nguyen, Carroll, Batzer and Jorder2001). The imposed conditions of substandard health and hygiene (relative to the conquerors) reinforced social separation through fear of contagion, where risk from biological contagion was readily confounded with social and mental contagion. Variations on this type of process, of course, marked the history of European colonialism as well (Stoler Reference Stoler2010).
Although ethnic exclusivity is probably as old as our species (Atran Reference Atran2001), in modern forms of nationalism it is more a social construction that stems in large part from the failed European political and social revolutions of 1848. These revolutions were fueled by ideologies preaching the emancipation of peoples and the dismantling of political and social boundaries. The lesson drawn by the victorious ruling elites to forestall future uprisings was that the “lower classes” must be made to feel themselves integral parts of exclusive nationalities steeped in common “blood,” but where rich and poor still had almost inescapably distinct derivations from the common national “essence” (Dowe Reference Dowe2001). These developments, again, reinforced the social and biological isolation of cultural groups and subgroups, including differential susceptibility and response to pathogens and parasite stress.
But it is with respect to the role of religion that the authors' arguments are most problematic. It is certainly plausible that “religious groups adopt their own distinct costly versions of supernatural beliefs in order to heighten costs of participation and distance themselves from out-groups” (target article, sect. 3.2, para. 3). Nevertheless, for at least the past three millennia or so, the most expansive and successful religions aimed to include as many genetic strangers as possible (Atran & Henrich Reference Atran and Henrich2010). Consider Christianity, the first truly universal religion, which still today has the largest group following on the planet. Originally attached to Jewish diaspora settlements throughout the Roman empire, it steadily gained a following of a few percentage points of the empire's population each year – especially among women, slaves, and other disadvantaged elements – until gaining a majority shortly before Emperor Constantine's conversion. Before Constantine's militarization of the faith in the fourth century, Christianity progressed mainly through costly, charitable acts of self-sacrifice, most notably in tending strangers with plague and other infectious diseases who were usually abandoned by their own kinfolk (Stark Reference Stark1997). The first true hospitals to care for the sick, including contagious lepers, were founded by Christians at Constantinople. Islam was militarized from the beginning, but realized its greatest expansion and flowering among non-Arab peoples (Berbers, Jews, Latins, Germans, Persians, Kurds, Turks, and so forth). With initial assistance from Christians, Islamic hospitals were tending those afflicted by infectious diseases by the beginning of the eighth century (Risse Reference Risse1999). Buddha also taught to tend the sick strangers, of whatever caste, so as to help eliminate all castes (largely a failure in India but very successful elsewhere). Pentacostalists and other Evangelical groups, as well as Muslim missionaries, are still converting millions in Asia, Africa, and the Americas through open-door charitable efforts (see Atran & Henrich Reference Atran and Henrich2010).
F&T claim that religiosity involves “an underlying mental mechanism” (sect. 3.2, para. 6) that encourages religious group similarity. This is misleading. There are no set principles or rules specific to religion, nor any adaptive religious complex that seems stable enough to undergo evolution by natural selection (Atran & Norenzayan Reference Atran and Norenzayan2004). Rather, religions involve a host of ordinary cognitive mechanisms (including those which produce fairy tales and supernaturals) whose distributions take on a characteristic religious aspect (in a “family resemblance” sort of way) in trying to deal with certain irresolvable but ineluctable aspects of the human condition (including “existential dilemmas” such as death, deception, catastrophe, and so forth). Moreover, in today's world, religions are as permeable as the transnational ideological -isms (actually, secular salvational monotheisms) that began to vie for domination of modern political life with the American and French Revolutions.
The inference that economic development “causes” religious decline and promotes democracy is also somewhat misleading. It is simply that institutionalized religions in the West were traditionally associated with older power structures. These have been largely replaced by secular political ideologies and parties, which continue to have “sacred” and transcendental (if not supernatural) aspects, whether attributed to Providence or Nature (Atran Reference Atran2010; Atran & Axelrod Reference Atran and Axelrod2008). The one consistent finding from political science is that the best predictor of democracy is not economic development per se, but the presence of a large and stable middle class. The initial rise of the American and European middle class was heavily religion-and-community based (de Tocqueville (Reference de Tocqueville1835/1984); Weber Reference Weber and Parsons1958). “Individualism,” which is a phenomenon largely associated with the demise of American community life in the later decades of the twentieth century (Putnam Reference Putnam2001), has become an analytic category chiefly because the country's major social analysts now recognize that much of the rest of world still has community-sharing traditions (“collectivists”). This is not because the rest of the world is more prone to parasite stress, and therefore more responsive to religion and less taken with democracy, but because modern forms of health care and hygiene, secular rights, and democratic governance, are all fairly new and still predominantly localized with the former colonial metropoles and their oldest former colonies.
Finally, even if parasite stress is significantly correlated with phenomena such as high religiosity or lack of democracy, that in no way informs us how religious or political systems are actually structured or modified under evolution. But, given the correlation data presented, parasite stress does merit further consideration as a possible selection factor in their persistence or hindrance.