The Making of the Mind: The Neuroscience of Human Nature (32 page)

But now consider other kinds of questions about our relationships with other forms of life. Do we, if ever, have a right to drive another species to extinction through hunting or other means such as destroying habitat? Is the manipulation of the genetic code—transferring a gene from one species to another—a violation of the way the universe was intended to be? Is it, bluntly, immoral? Are the lives and feelings of the warm, fuzzy creatures we domesticate—our cats and our dogs—worth more than those of the animals we consume for food? Are the cattle, sheep, chickens, and pigs that we consume for food worth more than the insects we squash and swat, or, for that matter, the bacteria we routinely ignore until they cause illness? As Gould notes:

These questions address moral issues about the meaning of life, both in human form and more widely construed. Their fruitful discussion must proceed under a different magisterium, far older than science (at least as a formalized inquiry), and dedicated to a quest for consensus, or at least a clarification of assumptions and criteria, about ethical “ought,” rather than a search for any factual “is” about the material construction of the natural world. This magisterium of ethical discussion and search for meaning includes several disciplines traditionally grouped under the humanities—much of philosophy, and part of literature and history, for example. But human societies have usually centered the discourse of this magisterium upon an institution called “religion.”
⁵⁴

Gould's concept of nonoverlapping magisteria may help humanity to see scientific inquiry and spiritual inquiry as compatible rather than competitive. In physics, remarkable progress has been made in understanding the origins of the universe. Cosmologists have concluded that the universe originated in the “Big Bang” nearly fourteen billion years ago. Prior to that discovery it was possible to assume that the universe existed simply because it always had existed in a steady state. Acceptance of the Big Bang theory by cosmologists, however, inevitably raises the question: From what did the universe originate? This is
the
ancient question of theology and philosophy. What is the nature of the first cause or the prime mover of the universe?

The famous philosopher Anthony Flew abandoned atheism in part because of the discovery of the Big Bang and its implications for a creator. He concluded that an eternal God is as good an answer as any to the question of the origin of the universe. The famous physicist Stephen Hawking, on the other hand, saw no point in positing a creator. In his view the universe is self-contained. That is to say, the space-time continuum has neither a boundary nor an edge, meaning that is does not have a beginning or an end.
⁵⁵
The expanding universe—a fact of the Big Bang—does not preclude a creator in Hawking's view, but he saw no need for one. As for the moment of the Big Bang, Hawking understands that
t
= 0, so one can in fact say that time itself had a beginning. But Hawking says that prior to this beginning, at
t
à 0, the concept of time is simply undefined and thus nothing can be said about it. Assuming this is correct, the question of first cause would seem to fall outside the magisterium of science. In Flew's words:

I concluded from this discussion that, even if it were agreed that the universe began with the big bang, physics must nonetheless remain radically agnostic: it is physically impossible to discover what, if anything, caused that big bang…. The moral of the story was that, ultimately, the issues at stake were philosophical rather than scientific.
⁵⁶

Our duality of intellectual inquiry exists only because the parts of the modern brain's ensemble make both possible. Coming to terms with this duality, then, will require learning to recognize the right teaching authority for the question at hand.

We, as twenty-first-century human beings, have inherited an amazing culture of spiritual exploration not only of the origins of the universe, but also of its purpose and destiny and our place within it. Religious thought and behavior has been part of human nature since our origins in prehistory. For the past four thousand years—just a fraction of our religious history—the monotheism of Judaism, Christianity, and Islam have informed the exploration of these mysteries for billions of people. The success of recent science—within the past one hundred years or so—should not precipitate amnesia for centuries upon centuries of religious insight. As Karen Armstrong reminded in her book
The History of Religion
:

My study of the history of religion has revealed that human beings are spiritual animals. Indeed there is a case for arguing that
Homo sapiens
is also
Homo religiosus
. Men and women started to worship gods as soon as they became recognizably human; they created religions at the same time as they created works of art. This was not simply because they wanted to propitiate powerful forces; these early faiths expressed wonder and mystery that seem always to have been an essential part of the human experience of this beautiful but terrifying world. Like art, religion has been an attempt to find meaning and value in life, despite the suffering that flesh is heir to.
⁵⁷

By the time of the “human revolution” of the Upper Paleolithic, the human brain had the key design features that make the human mind so distinctive and of a different kind from any other species. The modern ensemble of mind included an advanced working memory and social intelligence. Both of these were likely prerequisites for the invention of spoken language and the social transmission of language from one generation to the next. The symbolic thought language built upon was not only a powerful tool for communicating with others, but also for communicating with ourselves as the voice of the mind within us. With an internal language for commenting and an ability to draw causal inferences, the left hemisphere of the human brain became specialized as the interpreter of consciousness. Its capacity for inferring hidden causes at work in physical and social events encountered in the world provided a powerful boost beyond the purely perceptual causation capabilities found in nonhuman primates. Intellectual inquiry using the ability to infer hidden causes was potently leveraged by the recollection of specific past events and the imagination of possible future events. Mental time travel, the interpreter, language, an understanding of the minds of others, and the executive functions of working memory together made for a formidable mind.

The origin of modern human beings, according to both archeological and genetic evidence, was in Africa. From there, human beings migrated to other parts of the world, eventually reaching all the continents of the earth. As Luigi and Francesca Cavalli-Sforza noted in
The Great Human Diasporas
, four key dates have emerged from archeological findings:

The first date refers to the oldest modern humans found in both Africa and the Middle East around one hundred thousand years ago. Available dates do not distinguish clearly which is older, but earlier skulls from Africa appear to show signs of a trend toward modern human forms, strengthening many archaeologists’ conviction that
Homo sapiens sapiens
’ birthplace was in Africa. The presence of modern human sites to the west and east of Suez one hundred thousand years ago suggests that the journey from Africa into Asia (or, less probably, vice versa) occurred at about that time…. The first human vestiges in Australia and New Guinea have been dated at fifty-five to sixty thousand years ago…. The other two dates are more recent and indicate the times of the occupation of Europe (probably from western Asia, around thirty-five to forty thousand years ago), and America. The date for the latter is still rather unclear, unfortunately, but it almost certainly fell between fifteen and thirty-five thousand years ago.
¹

Converging with the archeological findings, the degree to which different populations of the planet share genetic similarities and differences also shows the major split occurring first between Africans and non-Africans.
²
The settlement of southwestern Asia and Australia occurred next, according to archeological finds, and the genetic distance to African populations is correspondingly closest. Asia and Europe come next in measured genetic distance as well as in the archeological records, with northeastern Asia and America being the last regions of the globe settled by modern human beings.

In the Upper Paleolithic era, from around thirty-five to forty thousand years ago to about ten thousand years ago, modern human beings unquestionably occupied regions in Europe. They left behind unmistakable evidence of a mind like ours in their Paleolithic cave art and carved figurines.
³
An abundance of engraved bones and carved ivory show two- or three-dimensional representations of animals. The limestone caves at Altamira, Lascaux, Pech Merle, and dozens of other locations in southern Europe became the work sites of skilled drawers and painters. Included in their images are stenciled outlines of the human hand, such as those positioned next to the images of the famed spotted horses deep in the cave at Pech Merle. Thousands of miles from Pech Merle, in the vicinity of what is now Yellowstone National Park in Wyoming, stands Legend Rock, covered with petroglyphs. These carvings in the stone
include a human handprint dated from about 10,700 years ago. Life-sized, the handprint was chipped out of the stone so it looked as if the hand had been pressed into the rock, as if the rock were soft clay.
⁴
Could there be a plainer symbol of the modern human mind's imprint on the world? The ensemble of the modern mind outlined in this book was there, thinking, talking, remembering, and creating at Legend Rock; by then the modern ensemble of mind had gone global.

The Great Leap Forward of the modern mind depended in part on an advanced working memory. One aspect of this was the enhancement of the executive-attention component of working memory, which allowed greater cognitive control and creative manipulation of mental representations. Another was the addition of a verbal working memory, which allowed the storage of words in the phonological form spoken by other human beings, as well as the storage of visual-spatial images of people, objects, and events. Whereas the latter enabled the power to learn, comprehend, and speak languages, the former enabled creative problem solving, planning, and mental flexibility.

Also in the creation of
Homo sapiens
came the capacity to think symbolically. Objects and events could be abstractly represented as words rather than as visual-spatial images. The modern mind was thus liberated from a purely perceptual train of thought. Besides bringing into working memory concrete objects and events that could be imaged like a picture, abstract concepts could also be represented as words and thought about through inner speech. The gift of language became a tool of solitary thought as well as a means of social communication. It is this capacity for symbolic thought—the use of words to refer to objects, events, thoughts, and concepts—that captures the essence of our species.

Language itself could not have been invented if it were not for an advanced social intelligence. We use language to communicate our thoughts and intentions to others and to try to influence their thoughts and intentions. This cognitive tool would not exist if it were not possible to understand other human beings as intentional agents with thoughts, desires, and perspectives of their own. We needed a theory of minds before we could invent a tool to change others’ minds. An advanced social intelligence also enabled human beings to collaborate in ways beyond the game of language, to empathize with the feelings of others, and to transmit culture from one generation to the next
through imitation and other means of social learning.

Regions of the left cerebral hemisphere, at least in the vast majority of human populations, were dedicated to the processing of language. Although the genetic basis for this adaptation is still not well understood, the human genome influences brain development in such a way that language inputs are preferentially processed by the left hemisphere, at least with respect to the sounds of words and their literal meanings. Two left-hemisphere networks known as Broca's area and Wernicke's area specialize, respectively, in the production and the comprehension of words. The left hemisphere also was dedicated to figuring out the hidden causes of events in the world. Inferring causation when it is not perceptually obvious is a powerful tool of analytic thought—science could not exist without it. Thus, in the left hemisphere of the human brain came a convergence that truly changed human history. Language—in an internalized form of inner speech—teamed up with causal inference to form the interpreter. The human mind could now explain the perceptions and thoughts that passed through conscious awareness. The inner chatter that accompanies most of our waking hours, and even accompanies some of our dreams, is of equal importance to human nature as the words we speak aloud to other human beings.

The ensemble of the human mind had one other component that possibly preceded some of the others. Namely, the system of long-term memory in humans underwent a specialization of declarative memory. Besides an ability to know a fact or a concept, human beings developed a capacity to recollect specific episodes from our past experiences. Besides knowing what occurred, we could reconstruct the when and where of it, too. Further, it allowed one to imagine an event occurring in the future using the same mental capacity. Human episodic memory, then, provided us with the capability of mental time travel, the ability to reverse the flow of time in our minds and to travel forward into an imaginary future. Because one of the functions of executive attention is to aid the effortful retrieval and reconstruction of past events, it seems likely that mental time travel required that an advanced system of working memory be in place first. It is also possible that language was a foundation for mental time travel. Certainly, human languages often provide a means for talking about the past versus the future. Yet did the invention of
verb tense first require mental time travel or vice versa? It is impossible to say with certainty. We can be certain, however, that the modern ensemble includes a capacity to roam into the past of our autobiographical experience, to venture forward into the imaginary future, to report those episodes to other people, and to comment upon and explain the causal factors at work to ourselves.

The brain networks that enable the five parts of the modern ensemble were in place tens of thousands of years ago. Even so, the mind of a Cro-Magnon from that era in the Upper Paleolithic in what is now the south of France would have lacked the hundreds of centuries of cultural innovations that have shaped our minds. The avalanche of technological changes of the immediate past century alone has created a profoundly different cultural environment for the mind of today. Despite our biological identity, all seven billion plus of us today on earth would regard a Cro-Magnon person as “the other.” Cro-Magnon prehistoric language, social customs, traditions, and beliefs would set them apart from any population now in existence on earth. Although Stone Age peoples—untouched by the modern world—were once still discoverable by anthropologists and psychologists, such isolation evaporated in the twentieth century. In an era when human beings have traveled to the moon and routinely look back on our planetary home from orbit, there no longer seems to be a place to hide apart from it all in prehistory. Have these cultural changes altered the way the contemporary mind functions compared with the mind of Cro-Magnon? If that is so, then how might the mind of the twenty-first century function differently as a result of the technological culture that now envelops us?

Such changes in mental functioning would appear inevitable because the mind is shaped by the culture as much as by the brain. The legendary neurophysiologist A. R. Luria conjectured how the human cerebral cortex acts as an organ of civilization. In the afterword to
Mind in Society
, Vera John-Steiner and Ellen Souberman described how Luria's views were shaped by his mentor Lev Vygotsky's emphasis on socialization in the formation of the human mind. In Luria's words:

The fact that in the course of history man has developed new functions does not mean that each one relies on a new group of nerve cells and that new
“centers” of higher nervous functions appear…. The development of new “functional organs” occurs through the formation of
new functional systems
, which is a means for the unlimited development of cerebral activity. The human cerebral cortex, thanks to this principle, becomes an organ of civilization in which are hidden boundless possibilities, and does not require new morphological apparatuses every time history creates the need for a new function.
⁵

The cerebral activity can undergo unlimited development by organizing new functional systems as a result of the social-learning experiences encountered during childhood. The culture in which the individual is raised can create new combinations of already-existing neural networks. The new functional systems can be built out of the existing modules and general resources of the brain, including working memory and long-term memory. For example, consider the three Rs of schooling. Reading, writing, and arithmetic are learned through immersion in a culture that uses, values, and teaches literacy and numeracy. The brain draws upon already existing neural centers for fine visual processing in order to perceive, represent, and manipulate letters and words in a written version of language. Similarly, written language can capitalize on the neural centers of Broca's area and Wernicke's area, which developed initially as brain adaptations for oral language. The processing of written language, then, is a new functional system built out of already-existing parts. Neither literacy nor numeracy requires the brain to change by evolving new adaptive structures across eons of geological time. Rather, within the existing structures of the cerebral cortex, new potential functions can find expression as human history advances and cultural evolution unfolds.

To bring our story to a close, this concluding chapter will examine how the modern ensemble might adapt to the remarkable technological innovations of the past century, indeed, the past decade. How might the Age of Information alter the mind? The Internet, laptops, smartphones, and 24/7 television now connect humanity in a global economy and information network that was unimaginable one hundred years ago. Such profound cultural innovation could precipitate the formation of new functional systems in the brain. Indeed, this has already happened before with the invention of writing and the cultural evolution of the literate mind.