The Pleasure Instinct: Why We Crave Adventure, Chocolate, Pheromones, and Music - Gene Wallenstein (2008)

Part I. The Pleasure Instinct and Brain Development

Chapter 2. How to Win Friends and Influence People

“I think therefore I am” is the statement of an intellectual who underrates toothaches.

—Milan Kundera, Immortality

Homo sapiens … can rightfully be called the babbling ape.

—Edward O. Wilson, Consilience

In most families there is nothing more exciting than the appearance of a new baby. In ours, the latest addition is my little niece Kathleen, who now in her fourteenth month can do so many amazing things, most of which we take for granted but are really miracles of development. A few months ago she joined the ranks of fellow bipeds and meanders about the house awkwardly, resembling a slightly inebriated little sailor making her way home after last call. She can recognize objects as being unique and distinct from others, no longer labeling everything uniformly as “daht.” And she has an amazingly complex palate of emotional expressions, the full range of which, I have come to realize, can be displayed with little or no notice. But this is just the beginning.

It’s been clear for many weeks that Kathleen can understand far more than she is able to verbalize. Sitting next to her at dinner the other night, I noticed she was trying to catch a balloon tied to the back of her chair. “Do you want me to get that for you, sweetie?” I asked. And then, all of a sudden, it happened—she said, “Yeah …” At last, contact! There was a real person inside that little body. Our brief exchange didn’t grab the interest of those around us, but I was astonished by the unexpected exactness of her answer. For the first time, I truly felt we had made a connection.

Later that evening while talking with a friend about my dinner conversation, I tried to explain why I was so taken aback by my niece. Surely it is to be expected that she’ll begin to talk sooner or later, but my surprise arose from two levels of awareness. On the first level, it’s staggering to think of the mechanistic and computational achievement it is to extract meaning from mere acoustic energy—sound waves thrust in your direction from the peculiar manner in which people modulate their breath as they exhale. The biological and psychological capacities that support the many processes in between auditory sensation and language interpretation can (and do) fill volumes in university libraries. Then there is the other side, language production. After Kathleen has interpreted my question and decided on an answer, she must mold her young articulators into the correct spatial arrangement, which varies over time, to create the proper sound waves that will have meaning for me, the listener. And finally, there is all that fancy neural processing in between language interpretation and production that is made evident when we realize that Kathleen’s answer does not result from some simple stimulus-response pairing, a monosynaptic reflex, or a bit of classical conditioning. Rather, a conscious, self-referential decision was made.

In his book The Language Instinct, cognitive scientist Steven Pinker marvels at this peculiar trick humans have evolved for communication:

As you are reading these words, you are taking part in one of the wonders of the natural world. For you and I belong to a species with a remarkable ability: we can shape events in each other’s brains with exquisite precision… . Simply by making noises with our mouths, we can reliably cause precise new combinations of ideas to arise in each other’s minds.

He makes the important point that the miracle of language is not just in its mechanics—sound waves bouncing off a cochlear, larynx, and pharyngeal openings constricted just so—but in the functional properties that emerge with its usage, namely the exchange of information that may come in any number of forms, such as those relating to nature, technology, social identity, physical health, emotions, and so on.

This brings me to the second reason I was so surprised by Kathleen. When she answered, “yeah,” I was impressed by her response on an intellectual level, yet at the same time, I felt an inexplicably strong emotional reaction, an attachment that formed instantly with this single syllable. I had heard her say words before, so it was not the mere occurrence of recognizable speech, but rather the context of the social connection that bound us that was so engaging. Just as the emergence of language has been shaped, in both the species and the individual, by the competitive forces of natural selection, so too has the appearance of emotions such as pleasure. The manner in which pleasure drives our biological need for social attachment and communication is the subject of this chapter, and it is an amazing story.

Precocious Primates

Ask an archaeologist what factors gave Homo sapiens the competitive edge over our neighbors—Homo erectus in Asia and Neanderthals in Europe—and they will likely describe the impressive transition from Oldowan stone tool use found at sites dating 2 million to 1.5 million years ago to the more sophisticated Levallois flake technology for making sharp blades.They will further comment on the explosion in variety and specificity of tools for different functions that appear in the archaeological record: elegant wood-carved spears used for hunting game; blades shaped into projectile points, end scrapers, chisels, and burins, all custom-made to match a particular task; and tools born from bone such as awls and needles. Ask anthropologists the same question and they will use the same archaeological data to remind us that earlier hominids tended to segregate their daily lives into different locations according to task.Tools were constructed in one location, food preparation in another, and so forth. Homo sapiens, on the other hand, are believed to have used a centralized location where all of these activities were performed together, providing an integrative and highly social aspect to everyday life.

But we are left with this daunting question:Why did this shift in social behavior occur? Put simply, why did our ancestors enter the “cognitive niche”? The survival of typical Homo sapiens depended critically on the possession of very basic factual knowledge and skilled techniques for managing their place in the habitat. They had to be able to locate food and know how to extract and prepare it for consumption. They had to learn where their predators were and how to avoid or defend against them. They needed to be familiar with the terrain and, at the very least, possess rudimentary navigation skills. The list goes on and on—just for basic survival. Such increasingly complicated knowledge can most effectively be learned in the context of a social community. In the words of British psychologist Nicholas Humphrey, such a community “provides both a medium for the cultural transmission of information and a protective environment in which individual learning can occur.” In this sense, the primary role of intelligence in higher primates is not to produce great works of art or advance scientific achievement, but simply to hold society together.

Once a species begins on the path toward socialization, it is as if they were thrown on an evolutionary treadmill, and there is no going back.The emergence of social interactions ultimately leads to ever-increasingly complex social behaviors, social emotions, and group conduct that in turn develop a need for yet more complex social skills. This process is known in evolutionary biology as a “ratchet effect,” somewhat akin to a gear that is only capable of moving in a single direction. The limiting factor, of course, is determined by the extent to which the adaptive consequences of social behavior outweigh its burden and eventual cost on successful reproduction. Those individuals who place too great an emphasis on socialization while neglecting other subsistence factors will have a reduced chance of survival into reproductive age and attracting a suitable mate.

Social interaction brings with it enormous potential for changing the way individual members of a group go about their day-today survival. Though basic subsistence is always challenging, life in complex societies such as those constructed by many primates is demanding in a very different way. There are clear benefits to be had for those members of the group who can manipulate the social structure of the clan by outmaneuvering their peers. Individuals must be adroit at reading the social cues of the group; predicting the consequences of their own behavior and that of others; and tallying the complicated balance sheet of advantages and losses that revolve around these myriad social transactions. Hence, social primates are required to be calculating beings by the very nature of the system they create and maintain. In such a system, social skill, communication, and intellect are inseparable.

The selection pressures that led to early hominids’ growing need for more sophisticated subsistence technology contributed to two important changes in their social and (2) they encouraged greater interaction across generations whereby the young learn about subsistence technologies from elder, more experienced teachers. These shifts markedly widened the age range of the communal setting, and brought the very young into contact with the very old, resulting in particularly difficult social challenges. Both the older and the younger members of a community tend to be most dependent on the core adults of the group; thus an evolutionary mechanism must exist to facilitate or encourage the adults to cater to the whims, desires, and needs of these two groups. There must be some adaptive benefit for the adults that outweighs the cost to them in caring for the young, old, sick, and infirm. That adaptive benefit, of course, is mediated by the pleasure derived from social bonding—the pleasure I found in the exchange with my niece.

Many scholars agree that two behaviors probably provided the survival edge that benefited Homo sapiens over their contemporaries: the evolution of social attachment and language. I believe that both social attachment and language evolved from selection factors I call proto-emotions. These are basic, instinctual emotions that are exhibited by many primates: pleasure, fear, anger, disgust, sadness, surprise, and the various hungers. Proto-emotions have a very quick onset and are short-lived, almost like a reflex. The social emotions—for instance, happiness, maternal love, sexual love, infatuation, pride, and admiration—differ from proto-emotions in that they consist of long-lasting behavioral and mood states that typically outlast precipitating conditions and increasingly depend on a capacity for self-reference and reflection. These are the modern emotions we experience today that evolved from conditions in our ancestral past, remnants of a prior age where life was lived as hunter-gatherers on the open plains of the savanna. In the pages that follow, we’ll explore how pleasure led to the evolution of social attachment and language, and most importantly, how it shaped the positive social emotions that reverberate through our lives so profoundly today. Why did our instinct for pleasure drive us to become such loquacious, social creatures? And how did this newfound love of gabbing, gossip, and group affiliation result in modern emotions such as love, lust, happiness, and joy?

The Language Link

We take for granted that language can illuminate what is subjective, the amorphous yet innumerable feelings, thoughts, and inklings that mix through our minds like hot and cold currents every moment of the day. We like to think that other humans share this dizzying internal menagerie, or at least some parts of it. But what would a dog say if it could speak a human language? Would a dog’s inner emotional experiences be close enough to a human’s so that a common lexicon might emerge? Could we really learn more about the thoughts and feelings of animals—what is in their hearts and minds—if we could decode their vocalizations?

The linguistic philosopher Ludwig Wittgenstein argued that all truths, be they emotional, moral, aesthetic, or intellectual, are known only through experience. He suggested that they lose their real value and meaning in the telling, and that language is merely a form of depiction, a representational system that inevitably fails to characterize our genuine nature since it can only work through analogy. Thus, even if we successfully decode an animal’s sounds, we could not truly understand them because language is but a mirror of reality rather than the genuine object, and an animal’s reality, as the argument goes, is too far removed from our own. Language is the finger pointing at the moon, not the moon itself. In cognitive science circles, this is known as the representation problem—deciphering how symbols, such as language, map onto subjective experiences, such as feelings and thoughts. The representation problem, of course, extends to all symbol-using species, and we will revisit it throughout this book.

A kissing cousin to this line of argument is the classic linguistic problem of induction—how one infers the referent of a word from a speaker’s vocalizations and behavior. Imagine you are a linguist encountering a newly discovered human population. One of the clan members shouts “agovi” as a turtle saunters by.Your first guess, probably, is that agovi means “turtle.” This is a perfectly reasonable inference, since at least in English, comments elicited by an object typically refer to the object itself. But this is premature because agovi may also refer to animals or objects that move slowly, have shells, are hard and spherically shaped, are smaller than a house but larger than a breadbox, or are the most important ingredient for soup.The induction problem shows that any attempt to determine word meaning strictly from behavior is in deep trouble, since there are simply too many possible interpretations for any specific action. How did the first language emerge, then, if we can’t even get past single words? I believe a reasonable alternative is that hominids’ initial foray into semantics, and perhaps the genesis of structured language, were driven not by their desire to label everything in sight, but rather by their common need to exchange emotional information.

How did proto-emotions, particularly pleasure, foster the evolution of modern language? There are many theories that are fun to consider. Did language develop in response to the increasingly complicated social lives our ancestors lived, or is it perhaps the other way around, a new tool that evolved for other reasons—a spandrel—that facilitated greater socialization? What did the first languages sound like and how did they facilitate social attachment and the development of modern emotions?

Although it’s impossible to jump in a time machine and listen in on a prehistoric town meeting, we can adopt a different strategy. We can look to a source of information that will help us decipher how the pleasure instinct may have shaped social attachment and linguistic life for hominids—the emergence of spoken language in children. This is not an attempt to resuscitate the old Haekelian idea that ontogeny (the development of an individual) recapitulates phylogeny (the development of a species).This notion is based on the assumption that the ontogenetic form being considered develops through a series of stages that are essentially re-creations of the adult forms of its evolutionary predecessors.We will employ a more modern view that has emerged recently, which instead emphasizes studying the embryological and developmental commonalities and differences among genetically similar species. This theoretical approach never arose in Haekel’s day because it depends on the modern science of genetics. We will use it here because learning how an infant becomes linguistic can tell us a great deal about how language arose in our species as an important tool for emotional expression. “The human race began to talk as babies begin to talk,” noted the psychologist Carl Johnston, “… in the prattle of every baby, we have a repetition in a minor key of the voice of the earliest man … by watching the first movements of speech in a baby, we see once more the first steps in articulate language, which the whole world of man took in dim ages long ago.”

The Trouble with Tribbles

In ninth grade I remember reading a novel set in the distant future where a highly sophisticated artificial intelligence program is implanted into robots, eventually giving them enough brainpower to take over the world from humans, outthinking our every move. If you want a more probable scenario, one that at least makes sense from an evolutionary perspective, our mechanized subjugators are most likely to be adorably cute little creatures—perhaps puppylike—that gain power over us by tapping into our emotions rather than our rational components of mind. For primates, cuteness is more than simply a disarming factor. In our robots, cuteness would ensure that humans promote their survival by taking care of them, pampering them as one might an infant, working for the benefit of their continued comfort. In short, we would develop many of the behaviors and feelings toward them that go along with social attachment. The process is reminiscent of an old Star Trek episode in which the away team that has beamed down to the planet below encounters a species of hamsterlike critters known only as Tribbles. Going against Spock’s counsel, the team brings the harmless creatures on board the Enterprise, to the delight of the crew, who notice that when petted, Tribbles sing a beautiful cooing song. Before long, playing with Tribbles becomes the primary recreation of the shipmates, who are unable to resist their fuzzy appearance and soothing sounds. Meanwhile, the captain and Dr. McCoy begin to realize that petting Tribbles stimulates them to reproduce, and before long the Enterprise is in a desperate state, about to be overwhelmed by the exponential growth of these little fur balls. Soon Tribbles are everywhere, popping out of the food replicators, cooing from inside the ship’s main computer consoles; they have reached every nook and cranny of the vessel. Only Spock, devoid of emotions, seems immune to their charms and quickly takes control of the situation by isolating these dangerously lovable creatures from the rest of the crew.

The survival of all mammals, particularly the social primates, depends critically on their ability to secure attachment and nurturance from those around them. In most primates this dependence is aimed directly at the mother, who becomes involved in a complicated species-specific exchange with her offspring, employing whatever version of “motherese” phylogeny has given her. In humans and other mammals, the exchange between parent and offspring that leads to bonding and attachment can be likened to a conversation. Even though structured language may be entirely absent in the species, a turn-taking of sorts occurs, with certain physical and behavioral characteristics of the newborn eliciting a nurturing response from the parent, which then evokes yet more stimulation from the newborn, continuing the cycle. In humans this exchange is partly composed of prelinguistic vocalizations at first, with rapid phonological development that mirrors emotional expression in the first twenty-four months.

Infants enter the world displaying a clear preference for the language spoken by their mother. For instance, studies have demonstrated that French babies as young as four days old suck a nipple more diligently when hearing French than when hearing Russian or English. Likewise, Russian newborns prefer to hear Russian rather than French or English or Italian. Detailed experiments following up on these observations showed that babies tune into the prosody (timing, stress, and inflection) of speech patterns, since playing tapes of the languages backward—which preserves most of the vowels and consonants but alters the melody—eliminates the preference. Hence, newborns are predisposed to pay attention to prosodic features of their mother’s voice. Indeed, infants instinctually take such pleasure from these melodic elements of speech that they can be conditioned using prosody as a positive reinforcer (a reward) in the same way as can be done using other pleasurable experiences, such as access to its mother’s milk.

These findings are less surprising when we remember that prosody conveys the emotional tone of a message. “Communication is successful,” it is said, “not when hearers recognize the linguistic meaning of the utterances, but when they infer the speaker’s ‘meaning’ from them.” Many of the linguistic cues used to express intention are nonverbal. Systematic variation in pitch, tone, and duration of sounds—the music of language—is the primary venue for the infant, and it is in these signals that babies generally show the greatest interest. The newborn is naturally attracted to prosodic cues precisely because they contain the emotional meaning of speech, the very part of the message that is both critical to its social attachment with caregivers and accessible to its preverbal mind.

Interestingly, mothers across the globe—from culture to culture—speak practically identical versions of “motherese” to their infants: a complex blend of exaggerated tonal variation, eyes widened with expressive facial postures, and prodigious use of the high-toned “Hmm?” Wherever there are infants, we encounter baby talk, and it would be naive to consider this a form of linguistic instruction; the baby is certainly not enduring grammar drills. Rather, it is the innate social and emotional responsiveness of these inquisitive Lilliputian bundles that compels adults—mothers, fathers, brothers, sisters, and the rest—to speak motherese. The tiny linguophile naturally searches the faces and emotional expressions of nearby adults, an effort in identification and novelty-seeking that promotes further stimulation from parents.“The development of linguistic communication is a story about the preoccupation among the human young with things that move—faces that wrinkle, eyes that dance, voices that undulate, and hands that wiggle through the air,” wrote child psychologist John Locke.“Parents obviously understand this and, correctly believing that more is better, exaggerate their facial and vocal movements when addressing their young.And to good developmental effect, for the cues to phrase boundaries are prosodic, and the cues to vocal turn taking include variations in pitch and gaze.”

Why does the infant pay attention to speech? It is surely not to learn the rules of syntax, widen its semantic base, or because it thinks language is an important mode of communication. No, the process of gazing into the eyes of those around it and eliciting motherese stems rather from the child’s basic, biological imperative to interact and connect emotionally with the people who nurture it. Infants orient toward the human voice, especially Mama’s, and lock on to her face, studying it with deep concentration. Why should they do this? What are the biological and psychological reasons for such persistent behaviors? Surely they are adaptive in that they draw the caretaker closer to the infant, allowing it to identify those who are most likely to offer affection and nurturance.

Babies continue to learn the sounds of their mother tongue during the first year of life, all the while maintaining their innate fondness for prosody and the other features of motherese. We will see in later chapters that the infant’s pleasure instinct for prosody has surprisingly long-term consequences, particularly for the evolution of aesthetic and musical preferences in the adult. For instance, synthesized sounds that have extreme pitch variations reminiscent of motherese evoke a feeling of pleasure in adults, who often associate them with happiness, interest, and surprise. Sounds that have a falling-pitch contour (high frequency decreasing to lower frequencies) elicit feelings of calm and relaxation. Imagine a parent who soothes a crying child with “Aahh,” or the meditation practitioner chanting “Ohmm.”Vocalizations that have a rising pitch contour have a very different effect; they tend to excite and grab our attention—“Hey!” From cross-cultural studies, it is clear that both natural and synthetic exaggerations in pitch have a universal appeal, whether they are embedded in music, speech, or song, presumably as a result of the same underlying biological mechanisms that have evolved to promote social attachment through our attraction to prosody.

An infant’s face also conveys emotional information directly to the caregiver, and they are incredibly talented mimics even at birth. Developmental psychologist Andrew Meltzoff was the first to demonstrate that newborns as young as forty-five minutes old are able to reproduce facial gestures corresponding to primary emotional conditions such as disgust (tongue protrusion), surprise (mouth opening), and sadness (lip protrusion)—even before they have seen their own face! Thus from the very beginning of life, human infants are busy employing and refining their methods of communication, and the primary topic of discourse is that of emotions.

While it is true that infants enter a linguistic babbling stage, a visual analog of this behavior is seen in their tendency to produce varied facial postures shortly after birth—another sort of babbling. Through trial and error, they learn quickly which expressions evoke an emotional response in adult observers. Adults, of course, learn the same lesson, and generate a number of facial postures and behaviors, eventually stumbling on the ones that elicit facial expressions in the infant that correspond to positive emotions. Emotions, then, are the first language we use. When an adult or an infant sees an emotional expression, it instantly gains information about the displayer’s current state. These talents translate to the linguistic domain, where squeaks, gurgles, and coos—the vocabulary of motherese—feed the emotional palate as well.

Studies have also shown that infants are born with a predisposition toward preferring abstract visual stimuli that look like human faces. Neonates a mere nine minutes old were shown different drawings before having ever seen a face—any face. They looked significantly longer (a common measure of preference) at a stylized pictogram of a normal human face, than at pictograms with exactly the same features but scrambled (a nose, mouth, eyes, and brows situated randomly on a circular “face”), suggesting they enter the world searching for kith and kin.

Just as prosody can be used as a pleasurable reward to condition infants, so too can the appearance of a human face. Newborns as young as two days old learn to alter their behavior (sucking and gazing) in order to maximize exposure to human faces. In fact, they master this task with astonishing efficiency, which tells us two very interesting things. First, neonates must be equipped with something that approaches single-trial learning, particularly when the task involves an evolutionarily significant variable such as the face. And second, the infant’s capacity for extracting emotional and intentional information from facial features has such critical importance for survival that the pleasure instinct has made the human face a most attractive and rewarding visual stimulus for babies (and, of course, adults).

We will find in later chapters that the human face has physical properties—such as lateral symmetry and exaggerated contrasts—in common with other stimuli that infants find naturally rewarding. Our evolved pleasure instinct for these visual features has lifelong repercussions for the development of aesthetics and physical attraction in the adult. Discovering which physical features the pleasure instinct nudges us toward during our first steps as neonates will help shed light on why certain aesthetic qualities, whether they are in faces, bodies, paintings, or landscapes, are universally appealing for humans. All of these inborn talents provide the neonate with tools for establishing an emotional communion with potential caregivers. One can hardly imagine the survival benefit to an infant who routinely engages inanimate objects (either through vocal or facial expressions) with no obvious human features, to the exclusion of their brethren. Nature is unwilling to take any chances with this most critical of objectives, the biological imperative to become attached to a caregiver, receive nurturance, and eventually become enmeshed into a broader social community. In the next few chapters, we will learn how this fundamental biological rule combines with embryological and developmental processes that regulate the growth and maturation of the human brain.