The males were more aroused by anal sex than females, but the very religious were again at the bottom of the male scale (5.0).  Similar to the female pattern, the moderately religious males were next at 5.3.  The atheists, agnostics, and spiritual males all reported the same level of arousal, at 6.3, yet another statistic where the spiritual resemble the nonreligious more than the religious.

The relationship between religiosity and emigration is interesting, as there are many parallels with the definition of r-strategists in the field of population biology. r-strategists migrate to new habitats quickly, reproduce rapidly, and disperse rapidly when those habitats are depleted. They are noted by elevations in several altruistic traits, such as mutual defense, cooperative foraging, and nest building (E. Wilson, 2000).  Extinctions of small colonies are highest at two points: at the beginning of colonization; and at the point the population has reached the maximum carrying capacity of its habitat.

Religiosity has a positive impact on colonial longevity, as documented in the Sosis and Bressler study (2003) of 19^th century communes.  The religious colonies in this study had a mean longevity of 35.6 years, while the secular colonies lasted 7.7 years.  Sosis noted that intragroup conflict and economic failure were the two most common reasons for commune dissolution.  Sosis’ costly signaling theory of religion proposes that the greater the behavioral regulations placed on the members, (e.g., celibacy and fasting), the greater the longevity of the commune.  However, as Sosis noted, there was no relationship between “costly signaling” and longevity in secular communes, creating a significant issue with the theory.  Sosis also noted that religious communes were more likely to organize around a charismatic leader than were secular communes. 

The relationship between religiosity and successful colonization is no doubt the result of the highly coordinated social behavior and mutual altruism practiced by organized religious groups, but of the eighty-three 19^th century communes studied by Sosis, only a single religious commune has remained active until today--the Hutterites. 

The ability of organized religious groups to withstand r-extinctions, or extinctions of new colonies, is certainly implied by the Sosis study.  A primary difference between colonies formed by cults and colonies formed by existing religious sects lies in the level of support from the parent population, either through kinship or religious ties.  Cults are more likely to isolate themselves, thereby sustaining the dominance and reproductive advantages of the cult leaders. 

But from a perspective of population biology, there are several factors that have a significant impact on the total reproductive output of a colony (or any population, for that matter), such as the numbers of females and males that are in an active relationship that supports reproduction.  Based on the results in table 2, the religious males have a substantial advantage over the nonreligious males, and this implies a substantial reproductive advantage.

This poses an interesting question: does religiosity improve the likelihood that a male will reproduce?  Across most sexually-reproducing species, the percentage of females that produce at least one offspring is greater than the percentage of males.  Religiosity in males seems to improve the percentage that sire offspring.

The religious also report higher levels of monogamy and longer relationship durations.  This should ordinarily work to improve reproductive yield, especially in cases where both parties desire children.  Interestingly, the desire for the religious to have religious partners, as noted in table 1, seems to be facilitating the matching of the desire for offspring, and ultimately reproductive output. 

The correlation between religiosity and male dominance, as noted in table 4, pertains to dominance within the male-female relationship, and is not directly associated with intrasexual, or male-male dominance.  The correlation between intrasexual male dominance, sexual dimorphism, and reproductive advantage has certainly been documented in numerous species, but how does male dominance over females impact reproductive rates?  

While the Gottschall study (2003) indicates that fertility rates were higher in cases of rape than with consensual sex, fertility rates pertaining to varying degrees of sexual coercion among monogamous couples is unknown.  But we can speculate that male dominance within a relationship improves sexual access by the male.  Following this line of reasoning, the very religious males, reporting the highest level of dominance within their relationships, would have greatest sexual access to their partners.  The fertility implications are significant, as they also desire more children than any other cohort.

This brings us to the issue of the reported elevation in orgasmic ability among the religious females.  The connection between male dominance and female orgasmic ability would certainly be an expected outcome of natural selection, and indeed, it has been documented with other species (Troisi and Carosi, 1998).  How this relates to the more submissive role played by religious females is speculative, but the Donald Symons’ hypothesis of the female orgasm as an inert embryological byproduct, like the male nipple, would be challenged by the fact that females that are more reproductive are also more likely to orgasm during intercourse.  This is not to imply that the act of female orgasm improves fertilization specifically, rather, it seems to facilitate the general process of reproduction.  The female orgasm would presumably provide a substantial reward to induce copulation, along with the neurological chain of events that promote romantic bonding, ultimately improving reproductive yield.  

The proposal that female orgasmic ability is an evolutionary adaptation that promotes female choice in mate selection may have some merit when applied to the religious.  However, mate selection may only be part of the orgasmic advantage, as long-term bonds seem to be facilitated by long-term copulatory orgasmic ability.  Note that the religious females reported longer average relationships, and remarkably, higher rates of copulatory orgasmic ability in those relationships.

But perhaps the most significant variable associated with the reproductive advantage is the desire for children.  As seen in table 1, this is strongly correlated with religiosity.  While the religious seem to be playing a very tactical game of reproductive advantage, they are, for the most part, unaware of this game.  Evolution has loaded the nervous system with simple, yet effective, sexual and nonsexual adaptations that promote reproduction. 

One of these adaptations is evident in the table below, where the survey respondents were asked to select a favorite odor from the following options: chocolate, coffee, vanilla, garlic, or a newborn baby. There is indeed a positive correlation between religiosity and the hedonic preference for the odor of a newborn baby in both genders, (r=0.11, p<0.0001), which could be interpreted as an evolutionary adaptation that improves reproductive yield. 

However, in this response, we cannot be sure that they were solely influenced by the odor cues associated with infants, and not some other sensory feature.  The neurobiology of parent-child bonding is complex, and involves the phylogenetically ancient olfactory system.  If indeed the hedonic preference for the odor of a newborn baby is genetically modulated, it is only one of many evolutionary adaptations that improve reproduction.

It is also interesting to note that this preference is one of the few instances where the spiritual resemble the religious.  The spiritual, or those that have a belief in a deity, yet no religious affiliation, actually look more like the atheists and agnostics in their questionnaire responses. Perhaps this unusual cognitive alliance between the spiritual and the nonreligious is explained by hemisphericity, or the  various mechanisms employed by the brain to resolve conflicts in the alternate behaviors and cognition promoted by the lateralization of the left and right cerebral hemispheres. 

The brain is a paired-organ; with each half specialized in cognitive and behavioral functionality (Demaree et al., 2005).  The left cerebral hemisphere is implicated with the propensity to apply single meanings to ambiguous targets, while the right hemisphere is prone to apply alternate meanings to the same targets (Faust and Lavidor, 2003). The general mode of left hemispheric cognition seems to be the reduction of ambiguity, which has been associated with political conservatism (Jost et al., 2003), which itself is correlated with religiosity. 

There is an interesting convergence along several different lines of neurocognitive research with implications for a special role of the left cerebral hemisphere in religiosity and political conservatism.  The first comes from the study of belief-bias, which has identified a left temporal lobe system in belief-biased reasoning, while the right lateral prefrontal cortex is engaged when subjects inhibit a prepotent response associated with belief-bias (Goel and Dolan, 2003).    

The assignment of people, objects, and events into “good” or “evil” categories is a recurrent theme in religious dogma, and the neurology supporting this assignment appears to be centered in the left parietal lobe (Newberg et al., 2001).  This region is also implicated in motor planning for the redirection of body movements, which may hint that the binary categorization of “good” and “evil” has its evolutionary origins in the neurology associated with the fight-or-flight instinct.

Within the left temporal lobe, asymmetrically large hippocampal volumes are correlated with higher levels of religiosity and refractory epilepsy (Wuerfel, 2004), further implicating the left cerebral hemisphere’s role in religious disposition.  But perhaps the most significant neurological relationship to religiosity lies with the dopaminergic system (Previc, 2006).  Also, see last month's edition. The dopaminergic system is an anatomically distinct arrangement of neural pathways that activate cortical and sub-cortical structures to facilitate motor-control, reward-anticipation, reward-seeking, and approach.

The dopaminergic system, implicated in romantic bonding, sexual function, meditative states (Kjaer et al., 2002), and reward prediction, makes it a prime candidate in the behaviors associated with religiosity and political conservatism.  The reproductive rates of the religious are better supported by a higher propensity for reward-seeking; however, to date, there is no direct evidence that the religious are elevated in their propensity for reward seeking.  

With the reproductive advantages of religiosity, why does agnosticism and atheism persist?  This answer to this may lie in the social integration of divergent cognitive styles, that is, optimization of one’s contributions and compensations within a social group occurs when individual brains are specialized for different sets of tasks.  This phenomenon is seen in vertebrates (Vallortigara, 2000), and our data pertaining to occupation indicates that the religious and nonreligious are performing different economic tasks. The religious and nonreligious seem to have developed a rather symbiotic division of labor, forming a sort of economic glue that counteracts their tendency for social and political conflict.  

In the aforementioned Sosis study of 83 nineteenth century religious and secular communes, 82 failed, following the general tendency of high extinction rates for small animal populations.  Over the same time period, the survival rate of cities with populations of over one million was one-hundred percent. 

Extreme levels of religiosity would seem to have an evolutionary cost, as the time and effort devoted to religious behavior leaves less time for technological and economic pursuits.  Indeed, secularism and technological change are highly correlated variables, and reproductively successful religious populations must maintain some level of integration with the economics, science, and technology of dynamic secular populations, while minimizing their negative impact on fertility.

It is certainly arguable that secularism, via a greater tendency for cognitive diversity, specialization, and technological change, has actually improved the carrying capacity of habitats, subsequently supporting larger religious populations. Ironically, atheism and agnosticism may indeed be an evolutionary complement to religiosity, and the evolutionary trajectory of human gene pool seems to be walking the fine line between reproductive effectiveness and technological progress.

The strong orientation of the religions toward the afterlife, morality, male dominance, heterosexuality, fidelity, etc., when combined with the genes that promote religiosity, is fundamentally a runaway evolutionary process emulating the Fisherian model of runaway sexual selection.  God, meet Darwin.

 Charles Brack, March 2008

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