07_Davies_5.html

Our Biological Nature

The physical nature of our senses puts severe constraints on what we find compelling. There’s an obvious regularity in visual art: it is created to manipulate color within the range of light that human beings can actually perceive. There are some works of art that use ultraviolet light: they are conceptual pieces, because we can’t perceive light in that part of the spectrum. We also don’t make art that consists of manipulations of magnetic fields, because we can’t perceive them. If we’d evolved in a world without a moon, the earth’s magnetic field would be much stronger and more animals might have evolved to detect it, according to physicist John Barrow.1 If this had been the case, we might (if we came to be at all) have whole art forms based on magnetic fields. Sight, followed by hearing, is our most important sense, explaining why we have so few art forms based on touch and smell.

The receptivity of our senses, including what chemicals our taste buds react to, the frequencies our ears are attuned to, and so on, are those parts of the world that were important for the survival of our ancestors. We’re unaware of the rest, except through measurement instruments we design to translate them into something we can sense, such as when we see “infrared” photographs.

What we commonly refer to as our sense of touch is actually a suite of biological sensory systems that perceive things such as pain, pressure, temperature, and body position. The receptors are not only in the skin, but in muscles, bones, and even the cardiovascular system.

Our sense of where our body parts are is known as proprioception, and this sense might contribute to our appreciation of dance. When people observe others doing physical motion, it activates the motor parts of their brains. Visual experience gets translated into proprioceptive simulation and appreciation, even if they are just sitting and watching.2 Personally, I have often felt, while watching a dance performance, my muscles subtly, involuntarily twitch in sympathetic response to the dancers’ movements.

Humans also seem to have “mirror neurons,” which respond both when doing an action and witnessing an action—but only when that action is viewed as intentional. For example, the motion of falling after being hit with a board is an unintentional motion that presumably would not activate mirror neurons. Dance is full of intentional movements on the one hand, as the dancers are making decisions about what muscles to move, but dance is an interesting case because the movements often are not obviously in the service of some clear practical goal, as the motions involved with stacking wood would be. Nevertheless, neuroscientists have shown that mirror neurons are activated in humans when experiencing both music and dance.3

Although watching a dance performance might activate the proprioceptive as well as the visual senses, it does not take advantage of proprioception directly. However, some activities are designed to make a person experience something by moving their bodies in particular ways. I’m talking about participatory dance, such as line dancing, which is primarily meant to be enjoyed as an activity and not as a show.

To appreciate a painting, you use your visual sense. To appreciate a piece of music, you use your auditory sense. Similarly, participatory dance is actually executed to be appreciated, stimulating the proprioceptive sense. Whether or not a piece of square dancing choreography is a work of art or not is not particularly important. The point I am making is that there are parallels in how they must be appreciated.

One of the ways that participatory dances are limited is that they generally are not intending to evoke any kind of emotional range. Square, contra, and couples dancing might evoke feelings of joy or titillation, but rarely are these kinds of dances meant to evoke, say, sadness. I have been swing dancing for many years and I can’t imagine how I would make up a sad swing dance routine. There could be proprioceptive “arts” that do, however.

For example, here is a simple one:

Title: Exhaustion

1. Get on the floor, on your hands and knees.

2. Hang your head.

3. Slowly move your torso up and down.

This idea is that performing these actions makes the audience (in this case, both the performers and the audience) get a sense of what it means to feel exhausted. Indeed, certain body movements are associated with certain kinds of feelings. For example, bending your arm is associated with acceptance and joy and extending your arm with rejection.4

Although dance choreography also consists of plans for how to move, I would not consider it a prototypical example of proprioceptive art because the intended audience typically watches other people execute the choreography. If it were a proprioceptive art, the “audience” would be the dancers themselves. Of course, I would conjecture that one of the reasons people enjoy dancing in front of audiences at all is to enjoy how it feels, and in fact the act of dancing appears to have benefits for general well-being. Performing dancers probably get an artful reaction from performance. It emotionally moves them at the same time they are trying to emotionally move the viewing audience.

The group Improv Everywhere performs ingenious performances in public, often without the public knowing, at first anyway, that a planned performance is happening. One of their works involved having multiple people listen to the same track on their portable music players. The track had instructions (e.g., “jump now”). The people listening had a great time, following instructions and doing the same things at roughly the same times.

We can now see a complex of artlike entities at several levels. The choreography for a dance piece is a work of art. Like a play script, it needs to be performed to be appreciated.5 At the next level we have proprioceptive art, consisting of the experience of the dancer executing the choreography. Finally, we have the performance as viewed by an outside observer as a further work of art. These three levels have analogs to theater, at the level of the script, the acting, and the show.

Why would it be so emotionally moving to position and move the body in certain ways?

In the past twenty or so years, cognitive scientists have found that a great deal of our higher-level, abstract concepts have a connection to more primitive, bodily concepts. This relationship is theorized to be metaphorical by linguist George Lakoff and philosopher Mark Johnson.6 That is, we understand an abstract concept by reasoning with simple bodily experiences, such as perception or action. For example, we understand time in terms of space. In English, we conceptualize the future as being in front of us (perhaps because as we walk forward, time changes too) and the past being behind.

In contrast, there are some languages that conceive of the past as being in front and the future behind us (perhaps because we can see the past, but not the future). Their speakers’ gestures reflect this too. What’s amazing is that even though cultures differ in where people perceive the direction of the future, every culture thinks of the future as having some direction, which is, when you think about it, completely metaphorical, since, strictly speaking, time does not have a spatial dimension.

This is all possible because of our minds’ incredible abilities of association. One study by psychologist Sascha Topolinski even found that people had positive associations with dialing phone numbers that spelled out happy words (e.g., 5683 spells love) as opposed to numbers that spelled negative words. This happened even when the letters were not written on the number pad!7

This theory has inspired a great deal of empirical work that supports it, and papers finding metaphorical effects are constantly being published. Just to give an example, loneliness feels cold.8 That is, people who are feeling lonely report that a room is colder than nonlonely people do in a room of the same temperature. (Rather than review all the studies here, I will mention them as needed to explain phenomena.)

We know that these associations are more than just the conventions of language, because the same sensory terms are used for the same kinds of things across languages (e.g., hot referring to high-arousal emotional states).9

We think of the up direction as being good and the down direction as being bad. This is reflected in the phrases we use: “I’m feeling up today,” “Her depression was in a downward spiral,” “Things are looking up.” Why might this be? An evolutionary explanation is that when people are standing upright, they are more likely to be awake, healthy, and, most importantly, alive. When they are bent over or down on the ground they are more likely to be sleeping, sick, or dead. It could be that our primitive understanding of such things influences all of our conceptions of value.

One can see how this insight applies to staging in theater and choreography. Bend someone over and, all else being equal, it looks more depressing than if he or she were standing upright. This is what inspired the proprioceptive artwork I designed above. We can clearly recognize emotion in body posture and dance. Proprioceptive appreciation of bodily position and movement is effective because our higher-level concepts are metaphorically based on them.

These metaphors affect religious beliefs as well. Many world religions have concepts of some kind of heavenly afterlife. Fewer have a version of hell. Often, this “good” afterlife or otherworldly place is associated with the sky in some way. The association of “up” with goodness and divinity, as well as the association of “down” with evil has persisted across cultures and time, even for the nonreligious. This probably seems obvious, but its implications are not. Some effects of this are downright weird. A study by psychologist Lawrence Sanna even found that people were more likely to give to charity after riding up an escalator than after riding down one.10

There are known reasons for this. First, as described earlier, we have a general association of goodness with aboveness and the upward direction. In addition to the normal bodily activities that predict this association (we’re down when sleeping or sick), scholar Jon Tolaas points out that as infants, we literally get love and resources from above: our much larger parents.11

Second, the upper field of vision tends to be associated with abstract thinking, religious thought, hallucinations in general, and distance (because more distant things tend to be higher in our field of view than closer things). Hallucinations more often happen in the upper field of view and eyes tend to deviate upward during them. Think, for example, of the eyes rolling back into the head during some kind of trance. Likewise, feelings of embarrassment and shame are cross-culturally expressed with the downward positioning of the head and gaze, while success and pride is often characterized by an upward posture.12

More broadly, there is a “social cognitive chain of being” that places gods on top, humans in the middle, and animals at the bottom. Morality is also associated with this metaphorical, vertical chain in our minds. According to this theory, beings can be thought of as being more or less morally virtuous by pushing them up or down the chain. We find animals as being more worthy of consideration if we humanize them and other people as being morally repugnant if we dehumanize them (a kind of reverse anthropomorphization). We get the reverse effect when we sanctify people as Catholics do with saints. A study by psychologists Kurt Gray and Daniel Wegner found that thinking of gods as more humanlike (anthropomorphizing them) results in people thinking of them as less morally virtuous.13

The consequence of this association is that people will find explanatory structures (such as a set of religious views) more compelling if they conform to the “up is good” metaphor. A religion in which a good god is associated with being below everything will seem less plausible. It’s almost a law of religion—good gods have got to be above us.

* * *

The sense of smell is often ignored in artistic works, and it’s understandable. For one thing, it’s a relatively weak sense. Day by day, the average human being doesn’t get very much information from smell, at least compared to vision and audition.14 Indeed, the accommodations people need to make when they are hearing or visually impaired are often obvious, but people who cannot smell anything rarely encounter difficulties. Another reason we don’t have a whole lot of olfactory art is that smells are hard to reproduce and difficult to clear out once released. Imagine the difficulty of a movie theater that had an olfactory “smell track.” You’d have to pump chemicals in that have the smells you want and then be able to get them out of the air so that they would not interfere with the next smell. However, even this was tried. Smell-O-Vision injected smells into the seats, triggered by the soundtrack, and Odorama consisted of scratch-and-sniff cards given to audience members. Unlike vision or audition, which carry information as a single form of energy (light and pressure waves, respectively), smell is receptive to numerous chemicals, each of which would need to be collected or manufactured. Making a music file is easy. Smell-O-Vision is a technical challenge.

Of course, there are huge industries that try to make compelling odors. Perfumes and colognes are obvious examples, but most of what we experience as taste is actually smell. The taste buds on our tongue taste only five things: sweetness, saltiness, bitterness, sourness, and umami (savoriness). A flavorist is a professional smell maker for foods. We often don’t know why people respond to smells the way they do, but some smells have real but inexplicable effects. For example, a study by consumer researcher Kyoungmi Lee found that the scent of vanilla has a calming effect. Some women, inexplicably, have an affinity for the smell of gasoline.15

Chefs are culinary artists. Although taste is what we normally associate with what they are trying to manipulate, food is actually a multisensory art form, involving not only taste and smell, but also touch (the texture of food is important to the experience) and vision (people won’t eat food like meat or vegetables when artificially colored blue).

So smell actually gets used in multiple art forms, including perfume creation, the culinary arts, and your occasional Smell-O-Vision.

Future technologies might make the smellable arts more feasible. For example, if we are able to stimulate the brain or olfactory nerves directly, we will be able to send in smells as neural signals rather than by pumping chemicals into the air that the audience inhales. If this sounds baffling I highly recommend Ray Kurzweil’s The Singularity Is Near for an idea of how sensory experience via direct brain stimulation might be possible.16

However it is possible that you cannot make a masterpiece with smell, as you can with painting and literature. Perhaps this is because it’s hard to put pieces of smell together in meaningful ways, as you can bits of color in a painting, words in a poem, notes in a song, or events in a story. You could expose someone to fifty smells, in some particular order, but at least in the cultures we have today, we would have a very hard time making sense of them. Even perfume shops keep cups of coffee beans to sniff between samples, because customers’ noses get overstimulated so easily and customers need to clear the olfactory palette.

* * *

Vision is our dominant sense, and hearing is the runner-up. What we like to hear is constrained by the biology of our ears. In terms of volume, for example, there is a level of quietness that we cannot hear because of the structure of our tympanum.17 Rather than being completely free to make any kind of sounds, musicians are Caged, forced to only make sounds that we can hear, using notes we can distinguish. Humans can distinguish one-twelfth of an octave in music (an octave is the distance between a note and the same note at a higher pitch). The only animals with better discrimination are bats. Macaques, for example, can only tell the difference between musical notes half an octave apart!

Phonemes are the basic units of sound in a language. Although they are typically thought to be meaningless, there is evidence that phonemes actually have meanings somewhat like words do. This theory is called phonosymbolism, or phonosemantics. Margaret Magus found that, for example, the sound gl is more likely than chance to be at the beginning of words the meaning of which have something to do with reflected or refracted light (e.g., glare, glint, glimmer, glow, glance, glisten, glitter). Phonemes also carry emotional connotations, as well as shape connotations. For example, m sounds are associated with curvy shapes, while plosives such as the k sound, are spikier. In one experiment by neuroscientists V. S. Ramachandran and E. M. Hubbard, people were asked to match two shapes to two different sounds (kiki and bouba). People consistently paired kiki to the sharp shape and bouba to the rounded, amorphous shape. Associations have even been found with tastes—oo is sweet and a (as in cat) is sour. There appear to be similarities with these meanings across languages. Participants in one experiment could guess the meanings of antonyms (e.g., fast/slow) in languages they didn’t know better than chance might predict. Although we can guess why these patterns are found (e.g., sn words are associated with nasal meanings because we use the nasal area to make the sound), more research has to be done before we will really know.18

It’s been shown that words with front-of-the-mouth vowels (like the ih sound in tick) are preferred for small, sharp things, and back of the mouth vowels (a in tall) are preferred for dull, large things. This could be because vowels in the front of the mouth tend to be of higher pitch, and when smaller things collide with the ground or other objects, the sound they make tends to be higher in pitch, forming the association that gets transferred to word preference. Another theory is that this effect occurs because vowel sounds have different sizes in the mouth. The vowel sounds in the following words correspond to increasing size: beet, été, pet, pat, tall. It turns out that your tongue moves farther back in your mouth as you make each of these sounds. The theory is that perhaps the larger space in your mouth gives people an association of the sounds with larger and larger sizes as the tongue goes back and the mouth opens wider. Also, for some reason, the “smaller” vowels are associated with brightness.19

* * *

Whatever the reason, the implication for compellingness theory is that people will find new, made-up words more compelling if their sound associations match the properties of the thing described. This has ramifications for product naming—you probably would not want to name a new knife a shooboo. Perhaps the name of a drug will influence whether or not people will take it. Chemotherapy drug names have significantly more sounds in them that are associated with lightness, smallness, and fastness, such as voiceless consonants, as in the drug name ThioTEPA.21

Another implication concerns what sometimes happens when there is a meaning that everybody understands which does not yet have a word associated with it. For example, English has the word orphan for a child whose parents are dead, but we have no word for a parent whose child is dead. Even though we all understand the concept, there is a “lexical gap.” This gap might be filled someday if this concept needs to be communicated frequently. What sounds will fill the gap will probably make sense given the associations we already have with the phonemes in English.

There are also tendencies to interpret cadence in particular ways. For example, the way mothers tend to speak to babies (known as motherese) emphasizes intention. They use exaggerated speech patterns characterized by high pitches, large pitch ranges, pauses, and a slow speed. Falling pitches soothe distressed babies. Approval is communicated with steep rising and falling pitches and disapproval is spoken in a staccato, low voice. This is not merely cultural. Babies can understand approval and prohibition phrases in other languages, as was found in a study of American and Japanese babies.22 A universal interpretation of cadence has ramifications for the interpretation of music.

* * *

The quality of speaker systems and sound-generation systems continues to improve, but the nature of the actual design of sound is already very good. There’s an inside joke in film sound design called the Wilhelm scream. First introduced in the 1951 film Distant Drums, the scream has been used over and over again in different films, and unless it’s been pointed out to you, you’d probably never notice that it’s exactly the same sound, over and over. We’re just not as sensitive to sound as we are to visual stimuli.

Yet, human beings can only detect a small range of color frequencies. The rainbow is a tiny slice of the electromagnetic spectrum. Our eyes have three working kinds of color-detecting cells, called cones. Our eyes reduce color to essentially three parameters: the amount of activation in the long, medium, and short cones. Everything else is thrown away undetected. There are many colors out there we can’t see, with information about the world we can’t access directly.

Trying to picture the colors we can’t see, such as x-rays, is as difficult as imagining a fourth spatial dimension. And by that I mean it’s impossible. We can imagine the concept of ultraviolet, but we can’t imagine it vividly.

Imagine having red-green color blindness (where only two of the cones are functioning) and then suddenly being able to use all three cones. It would be an awesome revelation. The addition of a single cone adds not one color, but multiplies the number of colors that can be experienced. Most birds have four cones, as do some fish and spiders. And apparently there are some women (called tetrachromats) who have four different kinds of cones! One negative aspect of this is that artificial visual media, such as photographs, television, and computer displays, are not optimized for the few tetrachromats and will exhibit crazy variation along those extra dimensions, making them unrealistic looking. The mantis shrimp, in one of its two very bizarre eyes, has eleven cones. It’s humbling to try to imagine the rich color experience of this creature.

We usually get visual stimulus from light in the environment, but sometimes we can experience light without any actual light at all. This can happen when using certain drugs or sometimes by pressing on our eyelids. The geometric shapes commonly seen in these conditions are called phosphenes and have neurophysiological bases. Some cultures interpret these shapes has having a mystical meaning.23

Just as we cannot appreciate music at frequencies beyond our hearing range, we cannot visually appreciate things too large or too small for us to comprehend. As art scholar Dennis Dutton points out, without the aid of a microscope we cannot even see the different parts of a flea in order to have any chance of appreciating its composition.24

* * *

Unlike literature, storytelling, and other art forms that rely on words, visual art can have a more universal appeal. Even people of cultures that do not have pictures can recognize objects in pictures. In this way, many of the visual aspects of film and theater can be appreciated cross-culturally. You can hand an excellent untranslated Chinese novel to an American child and she might not get anything out of it, but if you sit her in front of a Chinese film she will understand a great deal of what it is about, even if she understands none of the spoken words.

This is because much of human movement and expression is cross-cultural. We all understand fighting, walking, resisting, and so on. Similarly, the six “basic” emotions—namely fear, joy, surprise, disgust, anger, and sadness—have been found to be universally recognizable in facial expressions. These facts give visual media, such as film, theater, painting, and photography universal appeal when depicting human beings, especially human faces.

This is not to say that all emotions are easily read on the face. Nor are all expressions completely universal. For example, a Japanese person will nod her head and giggle to express confusion. Japanese art depicts anger with crossed eyes.

* * *

Some people have supposed that humans are the only creatures that can appreciate music. However, research by psychologist Adena Schachner found that species that can engage in vocal mimicry (e.g., parrots) can move in sync with music, suggesting that our rhythmic abilities grew out of our ability to speak.25 Interestingly, Charles Darwin suggested that our ability to speak grew out of what he called “rudimentary song.”

Cognitive scientist Tom Fritz exposed the Mafa (an ethnic group in Cameroon who had never heard western music) to excerpts of classical piano music. They consistently identified the same songs as sad or happy, suggesting that the emotional response to music does not depend on cultural background. Music researcher Roberto Bresin did research in which experts and laypeople moved sliders to adjust music to make it maximally sad, happy, etc. All agreed on which tempos were best for which moods.26

To some extent music mimics our voices. Neuroscientist Daniel Bowling found that when people (English and Tamil speakers) were speaking sadly their voices were more monotone. Similarly, Western classical music and Indian ragas both show the same pattern: sadder music has smaller intervals (the distances between notes in a melody) and happier music has larger intervals.27

Ultimately, much of music appreciation is metaphorical—musical elements deeply remind us of primal things we care about. Conductors have used the wrinkling of their brows to affect the sound of their orchestra. Journalist Justin Davidson reported that conductor Lorin Maazel produced a rich, honeyed sound from the string section in his orchestra by contracting his brow and a lyrical and light tone by lifting his eyebrows.28 It makes evolutionary sense to imagine that the upward direction is associated with lightness and the downward with heaviness. Heavy things are difficult to get off the ground. What’s interesting is that we describe music as being heavy at all. Lowering your pitch at the end of an utterance is associated with finality, rest, and completion. Ending a sentence with rising indicates incompletion. These speech associations have clear correlates in music.

Physically, sound is the interpretation of pressure waves in the ear, and heaviness does not enter into it. Why is a high-pitched sound interpreted as being, well, high? There’s nothing intrinsically high about it. Pitches are high or low because of a high or low wave frequency, of course, but we have no direct experience of this, and further, there’s nothing intrinsically high about a high number either. Why should we say that ten is higher than eight? Numbers are ordered, but there’s nothing intrinsically, spatially directional about them. We perceive higher pitches to be happy and lower pitches to be sad, demonstrating the conceptual metaphors that quantity means highness and that highness means goodness.29

* * *

What we see is linked to how we move, which is a part of why we like to watch sports. One of the reasons mammals play is because play simulates practice in dangerous situations. I conjecture that sports are an extension of this practice-play (note that in English and many other languages we “play” sports). Sports appeal to our sense of physical competition; we play sports for the same reason we wrestle with our children.

We don’t just play sports, though, we often just watch them. Why would we want to watch someone else playing, indeed, sometimes paying thousands of dollars to do so? In addition to the explanations provided elsewhere in this book, I believe that we vicariously experience the motion of the athletes just as we activate our motor brain areas and mirror neurons when we watch dance. So in a sense, we like to watch sports for the same reasons we like to play them.

In our minds, we are playing them.

* * *

Imagining yourself slam-dunking is all very well, but what of religious experiences? Scientists have found that they involve a few parts of the brain that are more and less active, depending on the kind of religious experience.

Three percent of Americans have had what are described as “near-death experiences.”30 The typical symptoms include experiences of approaching a bright light, seeing souls of the dead, feeling that one’s soul has left the body, and moving to another reality full of love and bliss, or sometimes terror. These characteristics are common in theological traditions worldwide, and there are physiological events that seem to trigger these experiences. For example, many of these experiences occur to people who are not near death at all, such as those experiencing sleep paralysis, high stress, or oxygen deprivation (which causes increases in dopamine). One diabetic patient had the classic symptoms of a near-death experience while having low blood sugar. Some experiences seem to be triggered by a failure to integrate information from the senses properly, which interrupts normal representation of the self and its relationship to the world.

There are interesting brain theories about the perception of a tunnel with light at the end. Pilots under high G-forces can sometimes experience a narrowing of the visual field that is often interpreted as a tunnel. This effect can also be caused by glaucoma. Blood and oxygen depletion in the retina can cause an experience of light as well as fear.

Visions of monsters, fairies, and dead people can result from a variety of conditions, including Alzheimer’s disease, Parkinson’s disease, and certain brain lesions. Stimulating one part of the brain (the angular gyrus) can result in a sense of a felt presence. Degeneration in the eye, as in Charles-Bonnet syndrome, can cause visions of ghosts or fairytale characters. One theory of hallucinations is that they are the result of one part of the brain interpreting noise from another, damaged part of the brain.

Sensed presences (in the absence of an actual other person) are often triggered by barren landscapes, monotony, darkness, cold, isolation, dehydration, hunger, fear, fatigue, and sleep deprivation.31 Of course, people experience supernatural beings without being under these conditions. According to anthropologist Scott Atran there is no known report by an anthropologist of two people perceiving the same supernatural being in the same way at the same time,32 further suggesting that these experiences are caused by mental processes and not by something in the real world. If a supernatural being actually appeared, it stands to reason that more than one person might experience it at the same time.

The bliss felt during some of these experiences could be caused by the surge we often get of dopamine and other opioids when under severe stress. Clearly, there is no simple explanation for why people have near-death experiences.

At the beginning of this chapter I focused mostly on traits of a healthy brain, but specific brain problems have implications for what’s compelling as well. In chapter 3 I talked about how schizophrenia-spectrum effects can create and support religious belief. A similar effect happens through obsessive-compulsive spectrum disorders.

Obsessive-compulsive disorder (OCD) is characterized by intrusive thoughts and a compulsion to engage in ritualized behavior to reduce anxiety. In particular, the intrusive thoughts often have to do with sexual or aggressive impulses, an aversion to or affection for certain numbers, or the belief that inanimate objects have souls. The rituals, which can absorb hours of the victim’s day, often have to do with cleaning (e.g., incessant hand or wall washing), hoarding (e.g., not being able to ever throw away a piece of paper), entering or leaving spaces (e.g., having to count to a certain number before entering a doorway), and checking (e.g., returning home again and again to make sure the stove is off). Often, the sufferers themselves know, intellectually, that what they are doing is irrational but are unable to stop.33 Failure to perform the rituals results in fear and anguish. It’s the fourth most common mental disorder, affecting 2 percent of all Americans.

OCD, like many mental illnesses, is probably the result of overactivity of mental processes that normally help us. It’s good for our health to keep clean. We sometimes forget things, so it’s good to check once in a while. We do sometimes have to do “rituals” to prevent undetectable hazards without knowing the actual connection between the ritual and the real-world effect.

It is likely that religious rituals are compelling because they activate these same functions—the same parts of our mind that, when in overdrive, result in OCD. Indeed, hyperreligiosity is a major feature of OCD. And society’s reactions to people with OCD can take a religious turn. Western society used to think that people with obsessive blasphemous or sexual thoughts were possessed by the devil.34

Further evidence that religious ritual is connected with OCD comes from the fact that religious rituals often have the same content and themes as OCD rituals. Orthodox religions are replete with food and body cleansing, repetition of mantras, numerology, and rules on how to enter and leave places. In Hinduism, for example, an orthodox Brahmin might spend six hours a day in cleansing rituals. Brahmins have rituals regarding which foot to put down first when getting out of bed, what they can’t look at when defecating, how to enter and leave a temple, how many times they must wash each hand, how to eat, and the reciting of sequences of magic numbers. There are hours of ritual before the first meal of the day.35 Orthodox Jews have a spectacular number of laws about food preparation and eating, ritualistic cleansing (including putting silverware in dirt), entering and leaving holy places, special numbers, the number of bones believed to be in the body, and the number of days in a year. Islam details rules about what to eat, how to enter and leave mosques, how to wash out the mouth, and which hand to wash in which sequence. When cleansing, if you touch your penis you have to start over.36 This requirement—that if the ritual is not done correctly, it must be started over—has a striking similarity with the rituals of obsessive-compulsive disorder—the repetition is why victims of OCD often waste hours every day.

Cultural and religious rituals are compelling often because it can feel dangerous not to perform them. Just as with OCD, the failure to perform can cause a vague sense of dread, even though the participants don’t have any clear idea of any mechanism that connects the ritual to events in the future.37 Because there is no apparent connection between rituals and events, it allows for rituals featuring what appear to be meaningless and arbitrary actions to become widespread.

People with OCD-spectrum disorders are often attracted to religion. A study by psychologist Craig Gonsalvez found that Catholics have higher levels of obsessive-compulsive symptoms than Protestants or the nonreligious, reflecting Catholicism’s ritualistic nature.38 Orthodox Christianity has its share of OCD-like characteristics: the number of prayers to the Virgin Mary, details of baptism (a cleansing), magic numbers involving the Holy Trinity, etc. These are just a few examples of how religious practices are similar to OCD ritualistic behavior. In the modern Western world, people have some freedom to choose a religion or church. If people have proclivities for ritual they will be attracted to a church that offers it.

Sometimes an individual will become obsessed with religious ritual, and religious people have taken note of such obsessions. Five centuries ago Ignatius Loyola described the condition of scrupulosity as being anxious and too obsessed with doing everything perfectly, and even described how religious leaders should help people with this problem.

The OCD cleaning symptoms are examples of evolved traits that work well in moderation but become problems when indulged in in an extreme form. People have an urge to clean; people with OCD can take it too far. Why do people have this urge to clean? They probably have an evolved psychological fear of contagion. People don’t want to be around obviously sick people, in general, and people don’t even want to touch the things sick people have touched. People claim to have an aversion to washed clothing worn by murderers or even by people who lose limbs in accidents. A number of studies by Carol Nemeroff have shown how this “magical contagion” belief works: people don’t want an AIDS patient to occupy a hospital bed after they’ve left it, which implies a belief in causality, which goes, weirdly, backward through time. One experimental participant said about the idea of touching a sweater worn by someone with hepatitis, “I’d feel it was contaminated in some way, not only that I could get hepatitis from it, but that it was somehow contaminated, it’s just not clean. I don’t really think you could get it [hepatitis] that way.”39 The description suggests that this is an old-brain bias, a deep-seated feeling that can be at odds with what we know intellectually. If you doubt this effect, try this thought experiment: imagine how you would feel putting on a newly washed shirt that Adolph Hitler had slept in. If this thought creeps you out more than the thought of wearing a washed shirt from some unremarkable person, then you are feeling the power of this effect.

Perhaps this is why we think properties like happiness and powers can rub off onto objects too. People pay lots of money for trivial items that were owned by famous people. If the belief in good contagion was as strong as that in bad contagion, there might be comparable ideas about contact between perceived lower and upper classes elevating the lower rather than polluting the higher. But there are not. There is an imbalance—the bad can contaminate the good more easily, or more effectively, than the good can improve the bad. In Hinduism, if a Brahmin and an untouchable make contact, it’s the Brahmin that is harmed and not the untouchable that is helped. What’s interesting about this imbalance is that it mirrors the effects of infectious disease. If a diseased person comes into contact with a healthy person, the healthy person is in danger of getting sick, but the diseased person will not get healthy as a result of the contact. One exception to this is the “virgin cure” myth, which holds that having sex with a virgin can cure some venereal infections, such as AIDS or syphilis. It doesn’t work, of course, and rather than being a harmless myth, it has resulted in the rape of young women and even children.

Unlike many dangers, microbial danger is invisible. Germs are too small to see, but they can still make you sick and kill you. But we had to evolve a way to avoid microbial danger anyway, using other indicators, other signals that, throughout our evolutionary history, correlated with infection. Many of these indicators are outward signs of sickness, such as spots, coughing, being dirty, etc. The problem is that it’s not obvious how these indicators are dangerous. If you know something about the physiology of sickness, you can come up with causal connections, but of course we did not evolve with this knowledge and our gut reactions still do not use them. That is, the ancient instincts to stay clear of people who look sick work relatively independently of our reasoning systems that come up with explicit theories about illness.

Once a culture decides that a particular group has some sort of contamination as a part of their essence, then the contagion reasoning system kicks in and the idea of even touching them triggers disgust. Anthropologist Pascal Boyer reports that in one culture, people would not have a blacksmith over for dinner for this very reason.40

When we have an intuitive reaction that we do not understand, religion often steps in to provide an explanation. So we get ideas of certain practices or objects being forbidden for religious reasons. Incest is a wonderful nonmicrobial example of poorly understood intuitions resulting in religious concepts: religions the world over claim that incestuous acts can cause natural disasters.

Although there are patterns to religious ritual, in that they often resemble OCD rituals in theme, there is certainly a strong component of arbitrariness. And although religious scholars sometimes generate reasons for the various parts of a ritual, for most people explanations simply don’t matter. Bells and incense symbolize nothing in particular in Hindu ceremony, and most people are fine with that. Interestingly, ritual displays are common in other social vertebrates and can appear just as arbitrary. For example, there’s a bird called a manakin that moonwalks to impress a potential mate. Superstitious rituals also appear to be arbitrary, but I don’t know of a connection except that the existence of both behaviors shows that people generally have no problem engaging with rituals that make no sense to them.

Another reason religion can be compelling is because some of its tenets correspond well with psychological experiences we, as humans, can have, such as getting high on hallucinogens such as “magic mushrooms.” Psilocybin, the active hallucinogenic ingredient found in select mushrooms, has been found to cause feelings of peace, intense happiness, and a sense of the unity of all things.41 The human mind can experience certain phenomena that religion can then interpret in a compelling way. Scientists have found there are ways to actually induce religious experience through brain stimulation. Though controversial in science, the Koren helmet is a device reported to induce feelings of a benign presence in some people. Some of these people attribute this to the experience of God.42 Strange experiences like this get interpreted according to whatever background belief system people have. The interpretation becomes part of the remembered experience, in that we don’t even see it as an interpretation at all, but as a direct perception. We then remember the experience as further evidence of the belief system that helped generate it. In this way belief systems are self-justifying.

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One kind of religious experience involves the feeling of being out of control of one’s body. These feelings are often interpreted as feeling possessed by another entity, and belief in possession is common to many religious traditions. However, the specifics of the attribution are culturally constrained, supporting the idea that possession is a confabulation generated by the one in the trance to explain the feeling. They base this explanation on ideas familiar to them from their culture, be they spirits, ghosts, deities, or demons. But if not supernatural agents, what causes the experience?

In schizophrenia, one can sometimes feel that one is not in control of one’s actions. In epileptic seizures, you lose your feeling of self, similar to the feelings people report when under “spiritual possession.” In somatoparaphrenia, you have symptoms such as loss of mind (e.g., possession) and loss of ownership (e.g., this leg attached to me is not mine). When people report being possessed, they report four broad kinds of entities at work in controlling them: (1) the self, (2) an alien, (3) a malfunctioning machine, and (4) an engineer. This effect can be induced with hypnotic suggestion and looked at with brain imaging techniques. These examples from mental disorders show that there is something in the mind that can cause experiences of dissociation of ownership and control. These mind functions might be the same ones in use in certain religious experiences.

Dissociative identity disorder (also known as multiple personality disorder), in which more than one distinct personality resides in a single person, has been suggested to be related to possession claims.43 This relationship is controversial, as is the very existence of dissociative identity disorder.

Another disturbing possibility is that women who claim to be possessed might be describing a rape or some other kind of sexual assault in a culturally acceptable way. Some suggestive bits of evidence for this are (1) the primarily heterosexual male spirit and female victim relationship, (2) vaginal or rectal entry of the spirit, during possession, or exit of the spirit, during exorcism, and (3) descriptions by many of the victims that sound like rape scenarios. In cultures where being raped is shameful, a victim, consciously or otherwise, might describe the traumatic episode in terms of the supernatural.

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Revelation occurs when a person endorses beliefs from what is perceived to be a nontraditional source, such as being told something by a god. There are several types, including divination (e.g., reading tarot cards), hallucination (dreams, visions, etc.), infusion of inspired wisdom, and embodiment (meeting a person believed to be a divine being incarnated).

Several religions hold that one of our primary goals should be enlightenment. There are different things that are supposed to happen upon reaching this state, and traditions disagree on what exactly the state feels like. One constant, however, seems to be achieving an escape from the discomfort intrinsic to nonenlightened existence. Some sects say enlightenment entails gaining a true understanding of the world. For some, when this happens, the enlightened person realizes that he or she is one with the universe, that the distinction between the self and the rest of the universe is illusory.

There is reason to think that this transcendental feeling is the result of quieting the left hemisphere of the brain. Neuroscientist Jill Bolte Taylor tells in her book My Stroke of Insight about how a stroke temporarily disabled her left hemisphere. She felt that she was one with the universe. It could be that the long hours of certain kinds of meditation required to achieve spiritual enlightenment are, at a brain level, quieting the constant chatter and theorizing of the left hemisphere.

One of the differences between the right and left hemispheres is that the right tries to capture reality more or less accurately, without embellishment or interpretation. The left, on the other hand, is constantly theorizing and finding patterns. The left hemisphere has been shown to be more important for dreams and hallucinations. We can see the curious effects of this in split-brain patients.

The left and right brain hemispheres communicate through a structure called the corpus callosum. People who have trouble with seizures sometimes get the corpus callosum cut so that seizures won’t travel from one half of the brain to the other. It’s akin to creating a fire line in the woods. The most remarkable thing about these split-brain patients is that for the most part their lives are unaffected. They feel no different and their performance on most tasks, following surgery, is the same.

However, because the different hemispheres control different sides of the body (the right hemisphere controls the left half of the body and vice versa), scientists can make experiments that pit the hemispheres against each other. In one experiment people were shown pictures, then asked to choose the most relevant among a group of objects. The trick was that the different halves of the brain were shown different pictures. This is possible because the right hemisphere is in charge of processing the left half of each eye’s visual field, and vice versa. In one trial the left brain was shown a chicken and the right brain was shown a snowy day. Now, if the right (controlled by the left brain) hand executes the action that picks the relevant object, it picks something relevant to the chicken. If the left hand is picking the relevant object, it will pick a shovel. The weird thing in this case is that when researchers ask the participant why she picked the shovel she will say she picked it because she needed to clean out the chicken shed—an answer that has nothing to do with the wintery image that made her pick the shovel in the first place. Why? Because the left brain is, for the most part, in charge of language. The right brain has no voice. The left brain confabulated a reason. The real reason the participant picked the shovel was because the right brain saw a snowy day. But the left brain made up a reason to make sense of the choice, and the person, apparently, believed it. It has been said that the whole reason we have a sense of self at all is because “self” is basically a theory generated by the left brain.

Another relevant split-brain experiment concerns how the different hemispheres deal with randomness. In an experiment by neuroscientist Michael Gazzaniga, people were presented with two keys, a left one and a right one. One of the keys (say, the left) would give a reward 70 percent of the time, the other 30 percent of the time. These percentages were never explained to the participants, but through trial and error they got a rough idea of these percentages. In this situation, the most rational thing to do would be to press the left key all the time, because it yields a better return. Indeed, this is what rats learn to do in the same situation. People, however, end up pressing the left key only 70 percent of the time—some part of their brains thinks it can outsmart the system and guess correctly when the left will actually pay out, which of course it can’t. This leads to less payout over time. Which side of the brain is that?

If you guessed left, you guessed right. The isolated right hemisphere will choose to press left all the time, wisely, just like a rat, but the left thinks it can outsmart the system.44 As in most things, the left hemisphere tends to dominate when both hemispheres are being used. If you can’t understand why always pressing the left button would give a higher payout, try asking your right hemisphere. Or a rat.

We might say we are of two minds about what we are. Our left brain says we are a single person, separate from the environment. The right might see no such distinction, but it can’t say anything, and we are often only conscious of its point of view when high on drugs or after thirty years of meditative practice.

Let’s bring this discussion back to religion. When we have unusual experiences, such as feeling one with the universe, they might be a result of right-brain activity. However, our religious interpretation of that experience is likely coming from the left brain. As you might expect, religion cannot be associated with one half of the brain or the other, and religious behavior does not preferentially correlate with activation in either one of the hemispheres.

Buddhists claim that after many years of meditation one can reach an experience interpreted as enlightenment. Meditation sounds relaxing, and perhaps for some people it is, but some, this author included, find it more like taking your brain to the gym. It’s hard work. The Dalai Lama urged neuroscientists to find a way to get the same results through brain stimulation. Apparently even he finds it onerous to meditate for four hours a day.

Buddhists interpret enlightenment as offering a view of the world as it actually is, a special insight into the nature of existence. Specifically, they see such revelations as evidence that the self, as distinct from other things, is an illusion, and that the self and the rest of the universe is a seamless whole.

It turns out that meditation reduces activation in the parietal lobe, which is the area that allows you to distinguish your self from your environment, and in the left side of the brain in general, which is associated with thinking in a more narrative and less holistic way. Indeed, people who are less in touch with their bodies (as measured by their ability to mimic the poses of mannequins) are more likely to have out-of-body experiences.45 It is likely that long practice of certain kinds of meditation allows one to willfully reduce parietal lobe or left hemisphere activation. To me, concluding that you are a seamless part of the universe because you’ve managed to quiet the part of your brain that differentiates yourself from the rest of the world is like concluding that light does not exist because you’ve trained yourself to close your eyes.

Why might mystics see the right brain’s opinion of the world as more valid? First, it’s difficult to shut the left brain up long enough for the experience of the right brain to become dominant. Perhaps mystics see that point of view as valuable because it is hard to attain—as my theory of idea effort justification would predict. Second, apparently enlightenment is a wonderful feeling. In her TED talk Jill Bolte Taylor mentioned that during her stroke, it was liberating to not have the left brain chattering at her all the time. The view of reality that the right brain provides is peaceful and happy. Since people want to believe what they hope to be true, this would be another reason for people to prefer it as a clearer picture of reality.

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In periods of anxiety, many people engage in milder versions of OCD rituals. Note how common superstitions, such as avoiding stepping on cracks and throwing salt over one’s shoulder, are arbitrary actions to keep supposed bad things from happening, such as being influenced by demons or breaking one’s mother’s back.

I suggested above that superstitious learning happened in animals when the environment was more unpredictable. Similarly, in human beings, superstitions seem to happen more often in erratic environments. Unable to control the world, people resort to controlling their own behavior. When events are perceived as surprising or salient for any reason, it triggers causal reasoning and the mind searches for an explanation.

For example, anthropologist Bronislaw Malinowski found that Trobriand fishermen had more superstitions in the open ocean, where catches were unpredictable, than in the inner lagoon, where catches were more predictable. In baseball, batters’ rituals can be extraordinarily complex. Interestingly, there are more rituals for the more unpredictable parts of baseball: hitting and pitching. Fielding, relative to hitting, is much more based on skill and less on chance, and as a result players have fewer magical rituals for it.46

Chaos is frightening, and when people are frightened, they are more likely to see patterns that are not there. In one experiment by Jason Braithwaite, people were asked if they could discern any pattern in some random noise. The ones who were about to jump out of airplanes were more likely to discern something.47 Pattern detection is not as simple as the level of dopamine—it seems that it’s a right-brain hemisphere specialty. The right hemisphere picks up more pattern in random noise than the left, and paranormal believers tend to have relatively more right-hemisphere brain activation than skeptics, who tend to be left-hemisphere dominant.48

Religion, particularly of the kinds that have beliefs that resemble superstition, should be more common in highly chaotic and unpredictable human environments.

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In Western culture, the belief in ghosts is amazingly pervasive. A Gallup poll in 2005 found that about a third of all people are believers.49 Ophthalmologist William Wilmer investigated some of his patients who appeared to be living in a haunted house. They heard bells and footsteps in the night. They felt physical sensations and saw mysterious figures. They experienced headaches and fatigue. The previous owners had had similar experiences. It turned out that this old house had a faulty furnace that was releasing carbon monoxide into the house. It’s odorless, but breathing it can cause visions, feelings of dread, and hallucinations.50 When the furnace was fixed, these symptoms went away.

It might seem that the explanation wraps things up just a little too neatly. One chemical accounting for so much of ghost folklore? It makes more sense if we look at carbon monoxide not just as being the proximate explanation for an individual family’s experience, but as the cause for many of the beliefs our culture holds about ghosts in the first place. That is, we believe that ghosts are more likely to be in old houses, make mysterious noises, and appear and disappear because these ideas were originally formed by people with carbon monoxide poisoning. This theory would predict that our cultural beliefs about ghost mythology got a foothold in the public consciousness around the time that carbon monoxide was prevalent in people’s houses. And indeed this is true: ghost stories proliferated after the introduction of gas furnaces in homes after the mid-1800s. There are some confounding factors to this causal connection, however. For example, people of the time were fascinated with all kinds of other spiritual phenomena, including mesmerism and animal magnetism.

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We evolved to survive and reproduce in a particular environment. There are things we need to sense, such as the sound of sticks cracking that signal the approach of another being, and things we don’t need to sense, such as ultraviolet light. If we’d evolved differently, we’d find ourselves compelled by different kinds of experiences.

Small genetic differences can even affect our appreciation: some people, due to a genetic characteristic, find the taste of cilantro to be similar to soap. As such, their appreciation of cilantro-based recipes is fundamentally different from that of others.

We evolved to be careful of contagion and to protect our own, and we developed other tendencies that affect our appreciation of arts and affect the resonance we have with religious practices and explanations. Moving away from biological and evolutionary reasons for why we find certain things compelling, we now come to the mind, and how its biases affect what rivets us.