A note at Digg.com points to an item in the Huffington Post asking this question. The Huffington Post—self-described as "The Internet Newspaper" which is a fair description, provided saying "newspaper" makes you think think of the London Sun or the New York Post—The Huffington Post, I say, apparently had a slow news minute and filled space with this item on "The Effects Of Serotonin On Spirituality." (Don't bother clicking the link, it's just there for documentation.)
The bulk of the Huffington Post-ing is a quote from a brief item in Psychology Today:
A team of Swedish researchers has found that the presence of a receptor that regulates general serotonin activity in the brain correlates with people's capacity for transcendence, the ability to apprehend phenomena that cannot be explained objectively. Scientists have long suspected that serotonin influences spirituality because drugs known to alter serotonin such as LSD also induce mystical experiences. But now they have proof from brain scans linking the capacity for spirituality with a major biological element.Well, not so fast, cowboy—proof's a strong word. First let's note that the Psychology Today item is dated Nov/Dec 2003. (Apparently the Huffington staff are a bit behind in their reading.) But from it we can follow up the original paper in the American Journal of Psychiatry. The AJP, very much to its credit, has all its contents online and searchable, from 1844 to the present. Here's the full text of the original paper.
It was published in 2003 and describes a study of just 15 "normal male subjects, ages 20-45." That's a very small sample to use as a basis for a general conclusion; especially, we should be cautious about concluding anything from it about females, or younger or older or less-normal males. (The authors do point out these limitations, but neither Psychology Today nor Huffington Post mentioned them.)
The subjects were given the Temperament and Character Inventory, one of the many psychological instruments designed to judge personality traits. It is the only one, so far as I can learn, which treats "self-transcendence" as a measurable trait. (The more common "Five-factor model" tries to put numbers to traits of Openness, Conscientiousness, Extroversion, Agreeableness, and Neuroticism.)
Anyway, the researchers used a PET scan to evaluate the relative density of receptors for the serotonin molecule in various parts of their subjects' brains; and then they tried to relate those differences of receptor density to differences in the traits found in the personality test.
The only solid correlation they found was that serotonin receptivity correlated strongly (p<0.001) with high scores on the spiritual acceptance scale, of which they wrote:
The spiritual acceptance scale measures a person’s apprehension of phenomena that cannot be explained by objective demonstration. Subjects with high scores tend to endorse extrasensory perception and ideation, whether named deities or a commonly unifying force. Low scorers, by contrast, tend to favor a reductionistic and empirical worldview.Given the uncertainties of personality testing in general and the limited scope of this study in particular, you would not want to take it as a basis for any sweeping generalizations. But it is an intriguing hint that your preference for what the Brights call "a naturalistic worldview" might be the product of your brain structure at the molecular level, and basically genetic.
Or—and this is almost as likely—there is the possibility that by persistently holding to a naturalistic world-view, you have altered the seretonin chemistry of your brain!