Part 6 (1/2)

Might music production and perception be viewed as having evolved through s.e.xual selection processes as a courts.h.i.+p display? Let us suppose that a preference for repet.i.tious and rhythmic acoustic sounds first emerged as a survival mechanism linked to advantages in brain development. As we have seen in earlier chapters, the preference for repet.i.tious and rhythmic sounds by newborns and babies prompts them to experience as much of these stimuli as possible, which in turn facilitates normal brain growth and maturation during synaptogenesis and synaptic pruning. Studies in rodents and primates have found that a lack of exposure to patterned acoustic stimuli immediately after birth and the months that follow has profound effects on the physiological and anatomical brain structures responsible for audition. These changes to normal brain physiology and anatomy produce marked deficits in normal hearing and functioning. Organisms with deficits in normal audition might have a greater risk of predation (since they can't hear a predator charging from behind) and other general safety concerns that decrease their likelihood of surviving to reproductive age. A receiver bias such as a preference for repet.i.tious and rhythmic sounds would thus have survival value and could certainly have evolved through natural selection.

But how does the pleasure we naturally find in rhythm lead to the eventual production of Schubert's String Quintet in C Major String Quintet in C Major or or Rhapsody in Blue Rhapsody in Blue? There is evidence suggesting that the evolution of music production has been driven by both natural and s.e.xual selection mechanisms. Clearly, music has effects on social communication and cohesiveness that may benefit the individual's likelihood of survival. My sense, however, is that s.e.xual selection has played as important a role in the evolution of music production as natural selection. Just as was the case for body symmetry, it is possible that an innate receiver bias in the form of a preference for repet.i.tious and rhythmic sounds could have been co-opted as a courts.h.i.+p display through s.e.xual selection.The fact that music is such an elaborate and complex adaptation makes for an even more compelling case. If a preference for rhythmic sounds becomes genetically correlated with the production of rhythmic sounds as a behavioral trait, a positive feedback loop could occur, leading to a Fisherian runaway process. Comparable to the peac.o.c.k's plume, this might lead to ever more elaborate displays to vie for the attention of the opposite s.e.x. The trouble with this argument is that it is considerably easier to suggest that music evolved as a s.e.xually selected courts.h.i.+p display than it is to find actual data supporting the claim.

Ironically, going back all the way to Darwin, there are far better examples of how animal signaling-such as calls and songs-serve as courts.h.i.+p displays in species of frogs and birds than how making music may serve a similar purpose in humans. Many species of birds, whales, and primates (for example, gibbons) use song as a s.e.xual display during breeding season. Some songbirds such as the winter wren use bits and pieces from songs they have heard, and rea.s.semble them to form new phrases. That is, they exhibit learning similar to that seen in human music making. Hence, winter wrens can often sing hundreds of different songs. There is now evidence that females from several bird species such as blackbirds, mockingbirds, and warblers prefer males that generate larger song repertoires. Many species of birds also sing songs that have key components such as refrains, symmetry, and reprises similar to what is seen in human music.

So there is a precedent for using signals that have some components in common with human music as a form of courts.h.i.+p display during mating. To demonstrate that human musicality evolved through s.e.xual selection as a result of an initial receiver bias for repet.i.tion and rhythmicity, however, we need strong evidence to support a number of basic necessary conditions (similar to the conditions we generated when discussing symmetry and proportion).

Condition 1 The preference for repet.i.tion and rhythmicity is expressed at or very near birth. The preference for repet.i.tion and rhythmicity is expressed at or very near birth. We have provided key evidence for this condition existing in audition in chapter 7 and for other sensory modalities in earlier chapters. We have provided key evidence for this condition existing in audition in chapter 7 and for other sensory modalities in earlier chapters.

Condition 2 The preference for repet.i.tion and rhythmicity generalizes across many object forms. The preference for repet.i.tion and rhythmicity generalizes across many object forms. As we saw in earlier chapters, infants take pleasure in both perceiving and producing repet.i.tion and rhythm in a number of different domains, including vision, somatic, vestibular (for example, rocking back and forth), and audition. Hence this condition is likely met given the acc.u.mulated evidence. As we saw in earlier chapters, infants take pleasure in both perceiving and producing repet.i.tion and rhythm in a number of different domains, including vision, somatic, vestibular (for example, rocking back and forth), and audition. Hence this condition is likely met given the acc.u.mulated evidence.

Condition 3 Music has signal properties (qualitative and quant.i.tative) that are similar to the repet.i.tious and rhythmic stimuli that infants enjoy and produce. Music has signal properties (qualitative and quant.i.tative) that are similar to the repet.i.tious and rhythmic stimuli that infants enjoy and produce. One way of providing evidence for this condition is to examine the statistical properties of the rhythmic auditory signals most enjoyed by infants and demonstrate a correspondence in music.There is some evidence for this already. As we have seen, infants and adults alike prefer rhythms built from consonant intervals such as the perfect fifth and perfect fourth, with small pitch differences in neighboring tones over dissonant intervals with high pitch differences. It has also been shown that infants prefer rhythms with sharply rising or falling pitch contours.This signal quality is common to both language (that is, prosodic cues) and music. Other evidence might come from showing that the repet.i.tious and rhythmic auditory signals that infants generate as a form of self-stimulation have similar properties to those seen in music.To date this type of study has been limited to demonstrating that some of the key components of musical expression also occur in infant babbling-for instance, repet.i.tion, abrupt changes in pitch contour, reprises, and refrains. One way of providing evidence for this condition is to examine the statistical properties of the rhythmic auditory signals most enjoyed by infants and demonstrate a correspondence in music.There is some evidence for this already. As we have seen, infants and adults alike prefer rhythms built from consonant intervals such as the perfect fifth and perfect fourth, with small pitch differences in neighboring tones over dissonant intervals with high pitch differences. It has also been shown that infants prefer rhythms with sharply rising or falling pitch contours.This signal quality is common to both language (that is, prosodic cues) and music. Other evidence might come from showing that the repet.i.tious and rhythmic auditory signals that infants generate as a form of self-stimulation have similar properties to those seen in music.To date this type of study has been limited to demonstrating that some of the key components of musical expression also occur in infant babbling-for instance, repet.i.tion, abrupt changes in pitch contour, reprises, and refrains.

Condition 4 Music production is a reliable marker of phenotypic quality. Music production is a reliable marker of phenotypic quality. Since music and dance have costs a.s.sociated with their production, this behavior might serve as a potential fitness indicator. Fitness itself is a vague term. Most often when we hear the word ”fitness,” we think of proxies such as general health, avoiding certain illnesses, heterozygosity in select genes, or any number of other traits. But for Since music and dance have costs a.s.sociated with their production, this behavior might serve as a potential fitness indicator. Fitness itself is a vague term. Most often when we hear the word ”fitness,” we think of proxies such as general health, avoiding certain illnesses, heterozygosity in select genes, or any number of other traits. But for h.o.m.o sapiens h.o.m.o sapiens with sophisticated cognitive functioning, fitness of the mind may also have been an important indicator. As we have seen, handicaps are often reliable fitness indicators because they are generated at the expense of diverting precious energy from basic system functioning (for example, from growth and immunocompetence) and are often very conspicuous signals that could attract the attention of predators (they are called ornaments for good reason). Music production and dance require large reserves of metabolic energy even for short periods, but we know that modern tribal societies often have ritualistic music and dance that can last many hours and even days. The closest Western equivalent is probably the all-night rave, where young adults typically in their twenties dance nearly continuously from dusk to dawn. with sophisticated cognitive functioning, fitness of the mind may also have been an important indicator. As we have seen, handicaps are often reliable fitness indicators because they are generated at the expense of diverting precious energy from basic system functioning (for example, from growth and immunocompetence) and are often very conspicuous signals that could attract the attention of predators (they are called ornaments for good reason). Music production and dance require large reserves of metabolic energy even for short periods, but we know that modern tribal societies often have ritualistic music and dance that can last many hours and even days. The closest Western equivalent is probably the all-night rave, where young adults typically in their twenties dance nearly continuously from dusk to dawn.Music and dance production also consume vast amounts of metabolic energy used by the brain to derive creative expressions that will attract the attention of potential mates. The overwhelming majority of energetic costs a.s.sociated with being a big-brained hominid are linked to that big brain. No body part or system even comes close in its energy requirements to the ongoing metabolic demands of our brain. Hence traits that are reliably linked to increasing the already high energy demands of the brain would be honest indicators of fitness in this broader sense.Miller has made some suggestions in this regard.”Dancing reveals aerobic fitness, coordination, strength, and health. Because nervousness interferes with fine motor control, including voice control, singing in key may reveal self-confidence, status, and extroversion. Rhythm may reveal the brain's capacity for sequencing complex movements reliably, and the efficiency and flexibility of the brain's 'central pattern generators.' Likewise, virtuosic performance of instrumental music may reveal motor coordination, capacity for automating complex learned behaviors, and having the time to practice.” If some of these putative a.s.sociations or others could be demonstrated through empirical studies, this would represent a major step forward in showing that the evolution of music was indeed driven, at least in part, through s.e.xual selection.

Condition 5 Adults who can produce music enjoy greater mating success (when all other potential confounding variables are controlled) than their unmusical counterparts. As with condition 4, this condition might also be extended to include dance. There is, of course, the anecdotal evidence about rock stars having magnetic-like attraction for members of the opposite s.e.x, but I suspect that there are so many confounding variables (for example, confidence, extroversion, wealth, exposure, fame) that it is practically impossible to draw any meaningful conclusions from such stories. To demonstrate that this condition is true, we need evidence from prospective, well-controlled experimental studies. One line of experimentation should be designed to determine if individuals who exhibit the best dance or music production ability are viewed as more attractive than their counterparts after being matched for certain covariables such as age, gender, and key personality traits. The second line of experimentation would support condition 4 as well as condition 5 by testing whether the individuals who are seen as being the most attractive are also seen as being the fittest. Such experiments should also attempt to answer the specific dimensions of fitness that are particularly relevant to music production and dance.To my knowledge, such studies have not been conducted to date and await a motivated researcher. Adults who can produce music enjoy greater mating success (when all other potential confounding variables are controlled) than their unmusical counterparts. As with condition 4, this condition might also be extended to include dance. There is, of course, the anecdotal evidence about rock stars having magnetic-like attraction for members of the opposite s.e.x, but I suspect that there are so many confounding variables (for example, confidence, extroversion, wealth, exposure, fame) that it is practically impossible to draw any meaningful conclusions from such stories. To demonstrate that this condition is true, we need evidence from prospective, well-controlled experimental studies. One line of experimentation should be designed to determine if individuals who exhibit the best dance or music production ability are viewed as more attractive than their counterparts after being matched for certain covariables such as age, gender, and key personality traits. The second line of experimentation would support condition 4 as well as condition 5 by testing whether the individuals who are seen as being the most attractive are also seen as being the fittest. Such experiments should also attempt to answer the specific dimensions of fitness that are particularly relevant to music production and dance.To my knowledge, such studies have not been conducted to date and await a motivated researcher.

Condition 6 Adults prefer repet.i.tion and rhythmic stimulation in many forms, even those unrelated to music production and perception. Adults prefer repet.i.tion and rhythmic stimulation in many forms, even those unrelated to music production and perception. A growing body of data indicates that adults are attracted to repet.i.tion and rhythm in many contexts across many sensory domains. Children and adults take pleasure from certain comfort actions such as rocking back and forth or producing repet.i.tive movements of one body part or another. Such movements are pleasing in their own right but also reduce tension and stress. Dancing, running, walking, swimming, s.e.x, and a host of related activities are other forms of repet.i.tive motor behavior that clearly please adults. A growing body of data indicates that adults are attracted to repet.i.tion and rhythm in many contexts across many sensory domains. Children and adults take pleasure from certain comfort actions such as rocking back and forth or producing repet.i.tive movements of one body part or another. Such movements are pleasing in their own right but also reduce tension and stress. Dancing, running, walking, swimming, s.e.x, and a host of related activities are other forms of repet.i.tive motor behavior that clearly please adults.

Language production and a.s.sociated social dynamics have a very specific rhythm that can be pleasurable. Indeed, experiments have demonstrated that when speaking, people tend to choose words that fit rhythmically into their statement-a type of melodic intonation of spoken language. The pleasure some individuals find in poetry, which depends strongly on rhythm and meter, is another example of our attraction to repet.i.tion and rhythmicity.

Many nonmusical sounds of nature that are rhythmical are pleasurable to adults and children. Judging by their impressive sales, quite a few people fall asleep each night to the soothing beat of the ocean produced by a sound generator. Other options include the sound of crickets, rhythmic winds, flowing brooks, and birds. As long as there is sufficient variation in the sequence and the sounds are rich enough to reflect the natural world, the rhythm is very pleasing.

Although many studies have examined our proclivity to prefer temporal order to chaos, clearly there is a need for more systematic research to map out the full extent of the sensory domains involved. I suspect that we have just touched the surface in really understanding how this preference presents itself in everyday behaviors.

Hence we have fairly good evidence supporting conditions 1, 2, 3, and 6, and we need quite a bit of additional data to convincingly support conditions 4 and 5. But I am convinced that evidence will emerge if we make the effort to conduct carefully controlled studies.

To this point, we have discussed two very different examples-one spatial and one temporal-that ill.u.s.trate the way the pleasure instinct can impact our everyday lives and behaviors. In the next chapter we will consider the manner in which the pleasure instinct places high costs on those individuals who abuse it. We are all equipped with brains that have evolved to face specific challenges and circ.u.mstances from our ancestral past. Many of these challenges and the conditions in which they originated are quite different from, and in some cases in direct opposition to, those that exist in the modern world. In a real sense, we are all of another time.The innate preferences that have been forged by the pleasure instinct to help facilitate brain growth and maturation have consequences far beyond our love of symmetry, proportion, rhythm, and repet.i.tion (to name just a few). Let us now turn toward the darker side of the pleasure instinct-addiction.

Chapter 11.

h.o.m.o Addictus Every form of addiction is bad, no matter whether the narcotic be alcohol or morphine or idealism.

-Carl Jung, 1963

Vices are sometimes only virtues carried to excess!

-Charles d.i.c.kens, 1848

Most people have no idea how much their brain changes on a daily basis.As you read these words, distinct neural ensembles are communicating with one another, shuttling electrical impulses across brain s.p.a.ce. In the process some of these neural paths become strengthened and others are weakened. This collective pattern of brain activity creates a map or neural representation of the information being learned. As we have seen in previous chapters, some things are generally easy to learn if they are related to an organism's overall fitness or survival. Information not directly related to important selection factors may be more difficult to learn if it has little or no fitness relevance. The degree of difficulty in learning something is generally measured by seeing how long it takes to master the new information. For instance, if you become nauseous after eating dinner at a particular restaurant, you do not need additional meals to form the a.s.sociation between sickness and the local greasy pit. This is true for all mammals. Rats that are made sick by ingesting tainted food will avoid the food and location where it was consumed after a single experience. In contrast, it takes much longer to learn and remember multiplication tables or word definitions, information that-one might argue-is not directly relevant to survival or reproductive success.

As a young professor, my scientific interests focused on understanding the changes that occur in the brain as something is learned and remembered. Deep in the medial portion of your temporal lobe, there is an area called the hippocampal formation, which lights up like Carnivale as you learn new information and begin to store it into long-term memory. A great deal is now understood about the cellular and biochemical changes that occur in the hippocampus and related structures during learning and memory. Changes of this sort are generally referred to as neural plasticity, a phenomenon a.s.sociated with a host of normal and abnormal conditions.

Many scientists who study neural plasticity also study addiction, since it is believed that the transition from casual substance use to dependency is accompanied by distinct changes in the way disparate brain regions communicate with one another. A number of modern treatments for addiction, as we'll see, focus on blocking these changes in neural communication. Such phenomena can be studied readily in mice and rats, although there are obvious limitations in making the conceptual leap from animal models of addiction to understanding the disease process in humans. My approach to help bridge this gap was to volunteer at a local adolescent facility for substance abuse to hear about the addiction process from people who have experienced it firsthand.

The building in which I was eventually to spend so many afternoons was an old converted Victorian house on the outskirts of downtown. I learned quickly that the treatment model at this facility was holistic. Kids aged twelve to seventeen years resided in the house for therapeutic periods ranging from roughly three to twelve months. A typical day included meals, four hours of school, individual and group therapy, medical appointments with physicians and psychiatrists, meetings with legal counselors if required, and family visits. Kids came from all over the West and for a variety of reasons. Some had been in trouble with gangs and been arrested repeatedly. Others were at the house for behavioral problems at school or home. A common theme among the kids was substance abuse that could involve alcohol and/or controlled substances, including prescription medicines.

From the beginning, I was deeply moved by the emotional stories I heard from the residents. Several common topics came up again and again, including childhood traumas such as physical, s.e.xual, and verbal abuse. Other kids were impacted severely by a single early event such as the death of a parent or sibling. After several months I began to see patterns in an individual's choice of drugs that seemed to map onto the particular circ.u.mstances that surrounded his or her life.

Alberto was a seventeen-year-old boy who had been repeatedly plucked off the streets of Phoenix by authorities for crimes related to gang activity. When I first met him, he didn't seem violent, but I knew Alberto had been arrested at least once for a.s.sault on a rival gang member. He wasn't a terribly big guy and, to me, he seemed almost easygoing. If anything, he projected a sense of detachment bordering on apathy.

Each resident partic.i.p.ated in group sessions three times a week. A session typically began with each resident giving a brief update on his or her current state and bringing up any problems to the group. Alberto never seemed to have any problems. Like many new kids, he seemed to think of group therapy as a ch.o.r.e that was best done as quickly as possible or avoided entirely. After the update period, the group would focus on one person and explore the circ.u.mstances that brought them to the house. During his first turn Alberto seemed painfully uncomfortable. He appeared unable to focus and became more and more frustrated with each pa.s.sing minute. The group, however, had seen this before and gave him time. Gradually he began to tell his story.

Alberto came to the United States from Mexico when he was eight years old. He and his mother moved into a small, two-bedroom apartment with other family members, including his aunt and uncle and their four children. He described his uncle as a chronic alcoholic with a quick temper who physically abused him and his cousins fairly regularly. Alberto attended school for a couple of years when he first immigrated to the States, but dropped out and got more involved in gang life in his early teens. By the time he was thirteen years old, Alberto had tried almost every drug available on the street and was selling methamphetamine with a crew of other kids and a connection out of Los Angeles that could be traced back to Mexico. His favorite drugs were methamphetamine and cocaine, both of which he consumed regularly.

One summer night, after a day of meth binging, he had a psychotic episode. He described the experience as a waking dream in which he heard angry voices yelling at him, but he could not understand exactly what was being said. He also felt worms crawling under his skin, and he picked violently at his arms, neck, and face until they bled. At some point in the night Alberto had a grand mal seizure and was raced to a local emergency room.The ER visit was followed by police custody. After several similar experiences, arrests, and detoxifications, Alberto was sent to our little house for full-time residential care.

The withdrawal state that he felt was fairly typical of cocaine and methamphetamine use: low arousal and a general sense of malaise. Almost all methamphetamine or cocaine users appear lethargic and extremely apathetic following detoxification. In contrast, Alberto described the feeling of a meth-induced high as being like a bull-strong enough to take on anything or anybody. It also gave him enough energy to keep him awake for days on end.The best part for him was often the antic.i.p.ated high and then the feeling that nothing could go wrong once the drug took effect. In the year that I worked at the house, I saw many ex-gang members. Almost all of them were addicted to methamphetamine and described a sense of invincibility while on the drug that made it particularly attractive given the toughness of gang life.

Although the most common addiction in the house was to methamphetamine, there were also a number of residents addicted to heroin or morphine. Those addicted to heroin or morphine often had noticeably different life circ.u.mstances surrounding their drug use compared to those using methamphetamine.

Christine was a pet.i.te blonde who could easily be mistaken for the cla.s.s valedictorian. She was often described by her peers as ”bubbly,” instantly likable, and very smart. She came to the house from Las Vegas after running from three other rehabilitation programs. Her guardian hoped that bringing her out of state away from friends to a residential program might prove more effective in addressing her heroin addiction. I first met Christine in a group therapy session. Based on appearance alone, most people would have never guessed that she was a heroin addict. Nor would they likely be able to fathom the strange world in which she was immersed while using the drug.

Contrary to many of the kids at the house, Christine actually embraced the program and was eager to partic.i.p.ate. In group sessions we began to learn about her surprising past. She was born just outside San Francisco, but moved with relatives to Las Vegas after her parents were killed in an automobile accident. In Vegas Christine often felt like an interloper, living with her grandmother and ailing grandfather. Shortly after arriving, her grandfather died and her grandmother sank into a deep depression. Christine was thirteen when her grandmother committed suicide, leaving her to fend for herself. She dropped out of school and lived on the street with a small group of other homeless teenagers. Her new life consisted of prost.i.tution and just trying to stay alive. One day a friend showed up with several small vials of pure morphine stolen from a local hospital and asked if she'd like to join her. Christine had tried other drugs by then, including pot, methamphetamine, and a host of prescription drugs. She described her first morphine use as a turning point in her life. She had never had a high like this before and felt an instantaneous warmth come over her entire body-almost as if a security blanket was being tucked around her by her long-lost parents. She felt safe and, for the first time in as far back as she could recollect, less anxious and sad about her life. Before morphine, she constantly worried about everything; now all that was gone.

Christine quickly made the jump from morphine to heroin and started to get involved in petty theft, mostly stealing jewelry and wallets from hotel rooms on the less glamorous side of town. After her second arrest she was sent to a juvenile detention program that was followed by her first rehabilitation program. She was arrested a third time for prost.i.tution less than three weeks after completing the initial rehab.

In group sessions, Christine described her gravitation toward heroin use as a logical choice, almost as if she were a pharmacist matching a treatment to a particular ailment. Her problem, of course, was extreme anxiety. The typical uppers such as speed, methamphetamine, and cocaine always seemed to worsen this state. Christine learned through her own trial and error that morphine, heroin, and s.e.x were all ways to ameliorate this anxiety and unrest.This process was not altogether different from the experiences of Alberto, who learned that methamphetamine often made him feel more confident and brave in gang-related circ.u.mstances that can easily be described as perilous. Time and again I heard similar descriptions of how a resident came to focus on a particular drug or combination. It was not long before my understanding of addiction at the neural level started to align with what I was hearing from these kids, who had lived the experiences. The stories I heard mapped well onto theories about how different brain structures sensitive to addictive substances modulate the pleasure instinct.

At present, there are at least three major theories of addiction, each involving biological and psychological components.We will discuss these in a bit, but before we do, it may be instructive to first think about addiction as a process that interacts with emotional systems-both biological and psychological in nature.

Researchers have often found it useful to separate emotions into two basic processes, one that represents the valence of the state (positive or negative) and another that describes the level of physical arousal (high arousal or low arousal). In this two-dimensional model, one can have positive feelings involving high arousal. This state occurs when the arrival of some positive event (for example, a loved one or the smell of a tasty cheeseburger) triggers pleasurable feelings. Contrasting this, the arrival of a negative event (for example, bad news or the immediate threat of physical harm) can induce a feeling of dread or anxiety.

It's important to remember that in this model, pleasurable feelings can also be elicited in the low-arousal state by the removal of a previous threat. Likewise, the removal or loss of a potentially useful event can lead to negative emotions. Psychologists like this model because it aligns well with experimental findings. For instance, the pleasure a.s.sociated with the introduction of a positive stimulus is typically accompanied by relative increases in clinical indicators of arousal (for example, blood pressure and cortisol levels). Likewise, pleasure elicited by the removal of a constant threat (or negative stimulus) is usually a.s.sociated with relative decreases in these same clinical indicators. In each case we have the same emotional end point, but an asymmetry in how one arrives at the destination.

Neuroscientists who study emotions from an evolutionary perspective also like this two-dimensional model since it corresponds well with the idea that emotions are important for identifying fitness indicators in one's environment. An example of this is the high positive correlation between an individual's facial symmetry and his or her perceived attractiveness by others (see chapter 9). Our world is full of fitness indicators that range from those that can be used to determine the ripeness of fruit to others that allow us to choose a suitable mate. This simple two-dimensional model of emotions extends naturally to the traditional view that hedonic states evolved as internal measurement devices for a.s.sessing fitness (see chapter 9). In this view, a given stimulus carries emotional value only if it can serve (indirectly or directly) as a fitness indicator.You might argue that this is a drastically oversimplified view of emotions, and I would agree. We will use it here only to introduce a perspective for understanding how the pleasure instinct relates to the initial attraction and subsequent abuse of drugs and other potentially addictive phenomena.

In this two-dimensional fitness model, pleasurable feelings occur with the presence of fitness benefits or with the absence of fitness decrements. Negative feelings occur with the presence of fitness decrements or with the absence of fitness increments.This model, although simple, is consistent with a large body of experimental findings in humans, nonhuman primates, and mammals.