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The God GeneReview - The God Gene
How Faith Is Hardwired into Our Genes
by Dean H. Hamer
Anchor, 2004
Review by James Sage, Ph.D.
Jul 10th 2007 (Volume 11, Issue 28)

In this volume, Harvard educated geneticist Dean Hamer presents the case for the genetic basis of religious belief and spirituality. The book is extremely well-written and clear, especially for those unfamiliar with the study of behavioral genetics and molecular genetics. Hamer skillfully weaves an argument for the connection between our human capacity for profound religious experience, the brain mechanisms involved in such experiences, and the genetic basis for those brain mechanisms.

While he is careful to explain that his title is a bit oversimplified (acknowledging that there is a suite of genes responsible for the brain mechanisms that allow for religious experience), he is also careful to explain that The God Gene is not about the existence of God. Rather, Hamer is attempting to understand how our human biology allows for us to have such profound experiences that are common to many religious traditions. In other words, just because we can explain the neurobiological and genetic basis of religious experience, this does not mean that there is no God. Hamer maintains that the issue of God's existence is neutral with respect to the investigation of the genetic basis of religious experience and spirituality.

Main Thesis

Hamer's main thesis can be divided into three main parts. First, Hamer sets out to distinguish religiosity from spirituality, focusing on spirituality's connection with profound, self-transcendent experiences (the kinds of religious experiences William James investigated in his famous Varieties of Religious Experience). Hamer details a reliable method by which to measure a person's propensity for such experiences.

Second, Hamer investigates the cross-cultural presence of such profound experiences, noting that the capacity for self-transcendent experiences is cross-cultural. But like most human capacities (reading, running, ability to digest lactose, etc.), the ability to experience spiritual self-transcendence varies. Some are more susceptible to such experiences, others are not. Hamer utilizes a number of different questionnaires to identify those who are at the upper end of this capacity. Making use of various populations, including siblings and twins who were raised together and apart, Hamer generates some significant findings (though, Hamer notes, these studies are somewhat limited in their sheer size and have not been repeated sufficiently).

Finally, after identifying those who report such spiritual experiences, Hamer investigates the genetic markers that might be held in common. In the course of his investigation (which requires labor-intensive laboratory work and some creative gene-marking techniques), Hamer reports that the VMAT2 gene sequence seems to be the key to understanding the difference between those who are likely to have spiritual experiences and those who do not. The VMAT2 gene sequence (or, more specifically, the A33050C polymorphism, a.k.a., the God gene) is responsible for coding for proteins that are implicated in monoamines (a group of neurotransmitters responsible for many forms of chemical addiction), which is the neurological basis of spiritual self-transcendence.

In what follows, I will elaborate on some of the details of Hamer's argument, touching on five key factors along the way: measurement, heritability, identifying genes, brain mechanisms, and selective advantage. Finally, I will provide a few critical remarks of my own about Hamer's work.


In order to study behavioral genetics, Hamer sets out to establish a technique of measuring profound religious experiences. He makes a distinction between religiosity and spirituality. Religiosity is measured in terms of church attendance, voting behaviors, and other social-scientific factors. Religiosity has been measured successfully for years by social scientists, and can be documented using a variety of techniques.

In contrast, Hamer is more interested in what he calls spirituality, such as the profound experience that leads to religious awakening, a sense of self-transcendence, and a feeling of connection with God. These are all experiential measures that are intimately connected to our neurobiology. In order to investigate the genetic component of religious life, this notion of spirituality is Hamer's focus.

With such a distinction in place, Hamer sets out to develop a reliable method of measurement. Building on the previous work of Maslow and Cloninger, Hamer adopts and refines scales of measurement based on self-forgetfulness (becoming so immersed in a task that one "forgets oneself" for a time), transpersonal identification (a kind of diffusion of oneself with something larger, such as nature, the cosmos, or God), and mysticism (an ineffable state of mind).

After some data analysis and cross-checking, Hamer concludes that these three traits "hang together" in statistically significant ways. These three traits, in other words, seem to be measuring something consistent. Collectively, Hamer refers to these traits simply as "self-transcendence" (the name of the instrument itself is the TCI, or Temperament and Character Inventory).


Hamer then sets out to collect data with this measurement instrument, and seeks several populations and subgroups to investigate. Because behavior genetics is a discipline that measures the relative difference between genetic influences (as opposed to environmental factors), collecting information about siblings and twins allows the geneticist to isolate the relative contribution of environment (shared and unshared) as well as genes (again, shared and unshared). In short, Hamer collects data that is conducive to identifying the heritability of genes correlated with high levels of reported self-transcendence. His results are that approximately 40%-50% of self-transcendence is heritable. While that doesn't sound like much, it is truly an extraordinary finding.

Identifying Genes

Next in his investigation, Hamer identifies various genes that might be candidates for the genetic aspect of self-transcendence. After a few failed attempts (there are, after all, approximately 35,000 genes present in the human genome), Hamer explains how he and his research team hit upon the VMAT2 gene sequence. The VMAT2 gene sequence is polymorphic and has three alleles. What Hamer found was that one allele (the A33050C polymorphism) is strongly associated with those who report high levels of self-transcendence. The VMAT2 gene sequence is responsible for coding for proteins that make up a group of neurotransmitters known as monoamines, which leads to the next piece of the puzzle: What is the brain mechanism by which the God gene generates spiritual, self-transcendent experiences?

Brain Mechanism

Monoamines are a group of neurotransmitters (including serotonin and dopamine) responsible for (or implicated in) a number of neuro-chemical phenomena, including the feeling of euphoria, positive emotion, and the propensity for addiction. Roughly speaking, monoamines are responsible for the "high" feelings we experience when we have ingested various controlled substances, stimulants, or psychoactive plants. What is important is that monoamines are the biochemical mediators for the interplay between experience and emotion (between the limbic-brain system and the thalamo-cortical brain system). In short, monoamines play a significant role in ineffable feelings of "self-transcendence" that Hamer's questionnaire measures.

(Parenthetically, Hamer also discusses the compelling results found by Andrew Newberg and his colleagues regarding the connection between meditation, spiritual experience, and the discovery that key parts of the brain undergo what is called "deafferentiation" or a relative decrease in neural activity. Newberg's book, Why God Won't God Away, is equally readable and worth exploring for those who wish to examine the neuro-chemical basis of religious belief. Unlike Hamer, Newberg does not attempt to identify any genetic contribution to the human propensity to experience self-transcendence.)

Selective Advantage

The final methodological component in Hamer's study is to identify a selective advantage for the God gene. Why does such a gene exist and persist? Why is spirituality such a common human trait? From an evolutionary point of view, what does the God gene do for us in terms of survival and reproduction?

These are not simple questions, and simple answers are not likely. In what is perhaps the most speculative chapter in the entire book (with the exception of the later chapters, which I discuss below), Hamer lays out a basic answer to this riddle: the God gene was (and still is) advantageous because it contributes to longevity and community.

In terms of longevity, religious and spiritual practice affords individuals greater scores on health (including favorable mortality rates, heart disease, hypertension, and cancer). In addition to this, spiritual people tend to benefit from positive, hopeful thinking (the placebo effect, or what Hamer calls the "power of belief"). Whether or not God exists, it looks like belief in God (or some equally transcendent being, force, or concept) contributes to survival.

In terms of community, religious and spiritual practice affords individuals greater group cohesion and reciprocity (emphasizing the "us" in the "us and them" dualism). And, what's more, children raised in such a community will likely adopt their parents' religion (i.e., religious beliefs tend to be socially conditioned while the capacity for spiritual experience is genetic).

While this outline of an answer is plausible, Hamer's treatment is necessarily abbreviated, and for good reason. He is a behavioral geneticist, not a psychologist, medical researcher, or evolutionary biologist. The task of identifying the selective advantage of the God gene is a significant project that requires considerable investigation.


Throughout his discussion, Hamer is careful to identify several "caveats" that readers should keep in mind. For example, he is careful to point out that the God gene (the VMAT2 polymorphism) is not a complete explanation of spirituality. There is much more to be investigated, and many more genetic contributions that must still be identified. Also, Hamer is careful to point out that The God Gene is primarily about the link between genes and our propensity for spiritual experience. That is, Hamer is addressing the genetic and neuro-chemical basis as to why humans hold religious beliefs, not the existence of God. In other words, while genetics researchers might be able to identify additional genetic neuro-chemical aspects of spirituality, this in no way settles the debate as to whether or not God exists.


In this final section, I wish to detail just a couple of concerns that I have regarding Hamer's The God Gene. First, there is a chapter devoted to exploring "The DNA of the Jews" that seems rather out of place. After re-reading the chapter, I am unclear on what question Hamer is attempting to answer. Perhaps other more astute readers will be able to make better sense of this chapter, and how it fits within Hamer's larger argument.

A second concern revolves around Hamer's discussion of "memes" and Richard Dawkins. While the "meme question" is fascinating and well worth exploring (i.e., How is religion, as a meme, capable of such success in human culture?), I'm not sure Hamer is the appropriate person to offer an answer. While we should welcome Hamer's suggestions, they need to be investigated and corroborated further by experts in the fields of religious studies, cultural anthropology, and philosophy.

This is related to my other concern involving Hamer's rather quick dismissal of Richard Dawkins. While I admit that Dawkins is a rather off-putting critic of religion and prone to creating considerable controversy with his rhetoric, Hamer rather quickly changes the topic to suggest that Dawkins is a fundamentalist atheist and that atheism is his religion (a criticism frighteningly close to a common, failed dismissal used by many creationists in order to discredit scientists).

This maneuver is disappointing because, first, it has little to do with Hamer's main point, and second, it has the unfortunate consequence of promoting black-and-white thinking about religion and science. Throughout most of the book, Hamer avoids the pitfalls of making science and religion out to be intellectual combatants. However, his unsuccessful attempt to attack and dismiss Dawkins might give some readers a false impression that science is ultimately in God's corner. For example, a reader who already disagrees with Dawkins might be encouraged to think that, given enough time, researchers like Hamer will be able to provide rational, empirical justification that contributes to the idea that God really exists. After all, why else do we have the capacity for spirituality unless God put it there Himself?!?

Of course, the relationship between empirical science and religious belief is not nearly so simple. In a time when proponents of religion are attempting to reject the basic methods of science while simultaneously embracing the theistic implications of science, we cannot afford to be unclear about such matters. Hamer's overall thesis could have been equally well supported without resorting to a rejection of Dawkins on such flimsy grounds.

Despite these few concerns, however, I am very happy to recommend The God Gene to any reader who wants to learn more about the link between religion (spiritual experience) and science (genetics and neuro-chemistry). Hamer provides a fine introduction to the field, and will provide most readers with an accessible explanation of his findings regarding the God gene.


© 2007 James Sage

James Sage is Assistant Professor of Philosophy at the University of Wisconsin-Stevens Point. In addition to teaching courses in epistemology, philosophy of science, and philosophy of technology, he also has interests in philosophical psychology and the history of science.


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