Phantoms in the Brain: Probing the Mysteries of the Human Mind (32 page)

Hence emotional changes alone cannot provide a complete explanation for religious preoccupation.4

The third explanation invokes connections between sensory centers (vision and hearing) and the amygdala, that part of the limbic system specialized in recognizing the emotional significance of events in the external world. Obviously, not every person or event you encounter throughout a typical day sets off alarm bells; that would be maladaptive and you'd soon go mad. To cope with the world's uncertainties, you need a way of gauging the salience of events before you relay a message to the rest of the limbic system and to the hypothalamus telling them to assist you in fighting or fleeing.

But consider what might happen if spurious signals stemming from limbic seizure activity were to travel these pathways. You'd get the sort of kindling I described earlier. These "salience" pathways would become strengthened, increasing communication between brain structures. Sensory brain areas that see people and events and hear voices and noises would become more closely linked to emotional centers. The result?
Every
object and event—not just salient ones—would become imbued with deep significance, so that the patient 128

would see "the universe in a grain of sand" and "hold[s] infinity in the palm of his hand." He would float on an ocean of religious ecstasy, carried by a universal tide to the shores of Nirvana.

The fourth hypothesis is even more speculative. Could it be that human beings have actually evolved specialized neural circuitry for the sole purpose of mediating religious experience? The human belief in the supernatural is so widespread in all societies all over the world that it's tempting to ask whether the propensity for such beliefs might have a biological basis.5 If so, you'd have to answer a key question: What sorts of Darwinian selection pressures could lead to such a mechanism? And if there is such a mechanism, is there a gene or set of genes concerned mainly with religiosity and spiritual leanings—a gene that atheists might lack or have learned to circumvent (just kidding!)?

These kinds of arguments are popular within a relatively new discipline called evolutionary psychology. (It used to be called sociobiology, a term that fell into disrepute for political reasons.) According to its central tenets, many human traits and propensities, even ones we might ordinarily be tempted to attribute to "culture,"

may in fact have been specifically chosen by the guiding hand of natural selection because of their adaptive value.

One good example is the tendency for men to be polygamous and promiscuous whereas women tend to be more monogamous. Of the hundreds of human cultures throughout the world, only one, the Thodas of South India, have officially endorsed polyandry (the practice of having more than one husband or male mate).

Indeed, the old adage "Higa−mous hogamous, women are monogamous; hogamous higamous, men are polygamous" reflects this state of affairs. It all makes good evolutionary sense, since a woman invests a good deal more time and effort—a nine−month−long, risky, arduous pregnancy—in each offspring, so that she has to be very discerning in her choice of sexual partners. For a man, the optimal evolutionary strategy is to disseminate his genes as widely as possible, given his few minutes (or, alas, seconds) of investment in each encounter. These behavioral propensities are unlikely to be cultural. If anything, culture tends to forbid or minimize them rather than encourage them, as we all know.

On the other hand, we must be careful not to carry these "evolutionary psychology" arguments too far. Just because a trait is universal— present in all cultures including cultures that have never been in contact—it doesn't follow that the trait is genetically specified. For instance, almost every culture that we know of has some form of cooking, however primitive. (Yes, even the English.) Yet one would never argue from this that there is a cooking module in the brain specified by cooking genes that were honed by natural selection. The ability to cook is almost certainly an offshoot of a number of other unrelated skills such as a good sense of smell and taste and the ability to follow a recipe step−by−step, as well as a generous dose of patience.

So is religion (or at least the belief in God and spirituality) like cooking—with culture playing by far the dominant role—or is it more like polygamy, for which there appears to be a strong genetic basis? How would an evolutionary psychologist account for the origin of religion? One possibility is that the universal human tendency to seek authority figures—giving rise to an organized priesthood, the participation in rituals, chanting and dancing, sacrificial rites and adherence to a moral code—encourages conformist behavior and contributes to the stability of one's own social group—or "kin"—who share the same genes. Genes that encourage the cultivation of such conformist traits would therefore tend to flourish and multiply, and people who lacked them would be ostracized and punished for their socially deviant behavior. Perhaps the easiest way to ensure such stability and conformity is to believe in some transcendent higher power that controls our destiny. No wonder temporal lobe epilepsy patients experience a sense of omnipotence and grandeur, as if to say, "I am the chosen one. It is my duty and privilege to transmit God's work to you lesser beings."

This is admittedly a speculative argument even by the rather lax standards of evolutionary psychology. But whether or not one believes in religious conformity "genes," it's clear that certain parts of the temporal lobe play a more direct role in the genesis of such experiences than any other part of the brain. And if the personal 129

experiences of Dr. Persinger are anything to go by, then this must be true not just of epileptics but also of you and me.

I hasten to add that as far as the patient is concerned, whatever changes have occurred are authentic—sometimes even desirable—and the physician has no right, really, to attribute a value label to such esoteric embellishments of personality. On what basis does one decide whether a mystical experience is normal or abnormal? There is a common ten−

dency to equate "unusual" or "rare" with abnormal, but this is a logical fallacy. Genius is a rare but highly valued trait, whereas tooth decay is common but obviously undesirable. Which one of these categories does mystical experience fall into? Why is the revealed truth of such transcendent experiences in any way

"inferior" to the more mundane truths that we scientists dabble in? Indeed, if you are ever tempted to jump to this conclusion, just bear in mind that one could use exactly the same evidence—the involvement of the temporal lobes in religion—to argue for, rather than against, the existence of God. By way of analogy, consider the fact that most animals don't have the receptors or neural machinery for color vision. Only a privileged few do, yet would you want to conclude from this that color wasn't real? Obviously not, but if not, then why doesn't the same argument apply to God? Perhaps only the "chosen" ones have the required neural connections. (After all, "God works in mysterious ways.") My goal as a scientist, in other words, is to discover how and why religious sentiments originate in the brain, but this has no bearing one way or the other on whether God really exists or not.

So we now have several competing hypotheses of why temporal lobe epileptics have such experiences. Even though all these theories invoke the same neural structures, they postulate very different mechanisms and it would be nice to find a way to distinguish among them. One of the ideas—the notion that kindling has indiscriminately strengthened all connections from the temporal cortex to the amygdala—can be addressed directly by studying the patient's galvanic skin response. Ordinarily an object is recognized by the visual areas of the temporal lobes. Its emotional salience—is it a friendly face or a fierce lion?—is signaled by the amygdala and transmitted to the limbic system so that you become emotionally aroused and start sweating.

But if the kindling has strengthened
all
the connections within these pathways, then everything becomes salient. No matter what you look at—a nondescript stranger, a chair or a table—it should activate the limbic system strongly and make you perspire. So unlike you and me, who should display a heightened GSR

response only for our moms, dads, spouses or lions, or even a loud thud or bang, the patient with temporal lobe epilepsy should show an increased galvanic skin response to everything under the sun.

To test this possibility, I contacted two of my colleagues who specialize in the diagnosis and treatment of epilepsy—Dr. Vincent Iragui and Dr. Evelyn Tecoma. Given the highly controversial nature of the whole concept of "temporal lobe personality" (not everyone agrees that these personality traits are seen more frequently in epileptics), they were

quite intrigued by my ideas. A few days later, they recruited two of their patients who manifested obvious

"symptoms" of this syndrome—hyper−graphia, spiritual leanings and an obsessive need to talk about their feelings and about religious and metaphysical topics. Would they want to volunteer in a research study?

Both were eager to participate. In what may turn out to be the very first scientific experiment ever done on religion directly, I sat them in comfortable chairs and attached harmless electrodes to their hands. Once settled in front of a computer screen, they were shown random samples of several types of words and images—for example, words for ordinary inanimate objects (a shoe, vase, table and the like), familiar faces (parents, siblings), unfamiliar faces, sexually arousing words and pictures (erotic magazine pinups), four−letter words involving sex, extreme violence and horror (an alligator eating a person alive, a man setting himself afire) and religious words and icons (such as the word "God").

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If you and I were to undergo this exercise, we would show huge GSR responses to the scenes of violence and to the sexually explicit words and pictures, a fairly large response to familiar faces and usually nothing at all to other categories (unless you have a shoe fetish, in which case you'd respond to one).

What about the patients? The kindling hypothesis would predict a uniform high response to all categories. But to our amazement what we found in the two patients tested was a heightened response mainly to religious words and icons. Their responses to the other categories, including the sexual words and images, which ordinarily evoke a powerful response, was strangely diminished compared to what is seen in normal individuals.6

Thus the results show that there has been no general enhancement of all the connections—indeed, if anything, there has been a decrement. But rather surprisingly, there's been a selective amplification of response to religious words. One wonders whether this technique could be useful as a sort of "piety index" to distinguish religious dabblers or frauds ("closet atheists") from true believers. The absolute zero on the scale could be set by measuring Francis Crick's galvanic skin response.

I want to emphasize that not every temporal lobe epilepsy patient becomes religious. There are many parallel neural connections between the temporal cortex and the amygdala. Depending on which particular ones are involved, some patients may have their personalities skewed in other directions, becoming obsessed with writing, drawing, arguing philosophy or, rarely, being preoccupied with sex. It's likely that their GSR

responses would shoot upward in response to these stimuli rather than to religious icons, a possibility that is being studied in our laboratory and others.

Was God talking to us directly through the GSR machine? Did we now have a direct hotline to heaven?

Whatever one makes of the selective amplification of responses to religious words and icons, the finding eliminates one of the proposed explanations for these experiences—that these people become spiritual simply because
everything
around them becomes so salient and deeply meaningful. On the contrary, the finding suggests that there has been a selective enhancement of responses to some categories of stimuli—such as religious words and images—and an actual reduction in response to other categories such as sexually loaded ones (as is consistent with the diminished libido that some of these patients report).

So do these findings imply that there are neural structures in the temporal lobes that are specialized for religion or spirituality, that are selectively enhanced by the epileptic process? This is a seductive hypothesis, but other interpretations are possible. For all we know, the changes that have triggered these patients' religious fervor could be occurring anywhere, not necessarily in the temporal lobes. Such activity would still eventually cascade into the limbic system and give you exactly the same result—an enhanced GSR for religious images.

So strong GSR itself is no guarantee that the temporal lobes are directly involved in religion.7

There is, however, another experiment that could be done to resolve this issue once and for all. The experiment takes advantage of the fact that when seizures become seriously disabling, life−threatening and unresponsive to medication, portions of the temporal lobe are often surgically removed. So we can ask, What would happen to the patient's personality— especially his spiritual leanings—if we removed a chunk of his temporal lobe? Would some of his acquired personality changes be "reversed"? Would he suddenly stop having mystical experiences and become an atheist or an agnostic? Would we have performed a

"Godectomy"?

We have yet to conduct such a study, but meanwhile we have already learned something from our GSR

studies—that the seizures have permanently altered the patients' inner mental life, often producing interesting and highly selective distortions of their personality. After all, one rarely sees such profound emotional upheavals or religious preoccupations in other neurological disorders. The simplest explanation for what 131

happens in the epileptics is that there have been permanent changes in temporal lobe circuitry caused by selective enhancement of some con−

nections and effacement of others—leading to new peaks and valleys in the patients' emotional landscape.