The World Inside Our Heads: ‘Human’ by Michael Gazzaniga

Have you ever wondered why you are different from other animals? Why do people form strong social bonds and organize themselves into large groups? How have we developed ways to understand what somebody else is actually thinking? Why do we have art and morality? What is it, exactly, that makes us human?This last is the complex question that neuroscientist Michael Gazzaniga addresses in “Human: The Science Behind What Makes Us Unique” (Ecco, 447 pages, $27.50). The book is an intellectual romp through the cognitive neurosciences, an attempt to bring everyone up to date about what we know about who we are. Interspersed with discussion of some of these intricate matters of scientific inquiry are a number of charming and intriguing questions — such as whether you would want to go on a date with a chimpanzee (probably not, if you value good conversation) and why the right side of your brain appears to be much dumber than the left (the left side is something of an intellectual factory, a workhouse generating connections, while the right is a kind of neurological academy, home to patient logic). But if we have assumed for too long that it is pure intelligence that sets us apart, and that, therefore, a brain’s main value has been in generating something like computing power, Mr. Gazzaniga urges us to appreciate the brain as a peculiar and complex whole, important not just in the way it generates human intelligence, but also in the ways it has shaped, and sometimes limited, its development. The right brain might not help us on a certain brand of intelligence test as much as the left, but it is, of course, no less a part of who we are.Throughout “Human,” Mr. Gazzaniga argues that all of the aspects that make us human derive from the unique processes and functions of the human brain. This is not so unusual an argument for a neuroscientist. Where he hopes to advance a more original case is in his argument that it is not just the size and structure of our brain, but how that brain evolved in a specifically social environment, that has made all the difference. The development of the brain within a social environment, he shows, is what has brought us to the present day, where humans stand as an enormously sophisticated evolutionary success story.Over the past half century — a half century of incredible growth for neuroscience, and for its role in the way we have come to understand ourselves — neuroscience has focused, Mr. Gazzaniga believes, on the psychological aspects of human beings, but has neglected to properly evaluate the importance of our socialization. In particular, Mr. Gazzaniga suggests, most neuroscience, centered around the individual brain, overlooks how much time our brain spends interacting with others, attempting to understand others, and comparing ourselves to others within a social context. This is an important argument, although it is always difficult when dealing with the human brain to show that any one factor has been truly determinative. Social influences clearly play a large role, but so do individual thought processes and experiences.How is the human brain unique? There has always been the general assumption that it is the size of our brain that has set us apart. But as it turns out, size is only part of the equation. It is the complex organization and structure of the different nerve cells and their connections that ultimately differentiate human beings from all other animals, including primates. This “wacky arrangement” enables our brains to develop extraordinarily complex functions that help us to engage in critical social behaviors. Without these functions, we wouldn’t have language, empathy, and morality. Of course, what is still missing is why this arrangement of nerve cells has resulted in these functions. Today’s research can point to the parts of the brain that appear to be involved in morality — the emotional parts that help us evaluate situations and the frontal lobes that enable us to consider moral questions — but that does not answer the deeper question as to how, exactly, a sophisticated system of behavior such as morality arises from the firing of different neurons.If it is not simply the size of our brains that has pushed us ahead, Mr. Gazzaniga suggests, it may be the size of our social networks. It appears that chimpanzees can maintain social group sizes of approximately 50 to 55 members, while human beings can be organized in social groups as large as 150 to 200. Mr. Gazzaniga argues that the complexity of the brain itself correlates with the size of the social group that can be formed, and that this relationship played a tremendous role in the evolutionary development of human beings, allowing us to form larger communities and ultimately large-scale societies — forms of social and intellectual organization that have enabled humans to flourish while our primate cousins, by comparison, languish.It is not, however, enough, Mr. Gazzaniga suggests, to merely have a brain capable of such social structure; a number of particular functions are required to maintain our social groups. Language, of course, is of primary importance, since it allows us to communicate with each other, and the human brain and, in fact, the human head, had to develop in a very particular way to allow our highly complex language to arise. Most people do not realize that it is not simply the ability to understand language that is unique to humans, but that the rest of our head has the ability to speak it. The human vocal cords, tongue, and mouth all function in highly coordinated — and highly unusual — ways to generate spoken language.Morality is another unique feature of human psychology, and Mr. Gazzaniga cites some fascinating research on the relationship between moral reasoning and the human brain. Because we can recognize and empathize with the suffering of others, we develop an idea as to how to alter or avoid that suffering. This ability to feel someone else’s pain is tantamount to our development as social creatures, and is crucially important. Since we also have a sense of what is painful and what is not, we can develop moral concepts to help protect against people doing bad things to other people or to ourselves. Ultimately, this helps to form a more cohesive social group, since we are able to develop codified rules by which we can live and maintain our social structures.Toward the end of the book, Mr. Gazzaniga tackles the tangled question of human consciousness. For many, consciousness is the human trait that most clearly differentiates us from other animals. Mr. Gazzaniga argues that “consciousness is an emergent property” that arises from the biology of the brain — the particular bundle of cells that occupy our skulls. Consciousness is a highly complex process that helps distinguish human beings from other animals, he writes, but it does not represent some “special energy,” and does not occupy some supernatural realm. It is, he says, right there in the neurons. In fact, he concludes by stating that consciousness is built, brick by brick, by our perceptions and experience. Thus, human consciousness is so vibrant because we have so many different ways of thinking, feeling, and experiencing the world. For those of us studying changes in human consciousness, this is certainly a plausible idea, but for many, conscious experience seems to be more than simply a matter of biology, something closer to the notion of a human soul, and not tied to the material part of who we are. While the more ethereal concept of consciousness is not readily embraced by scientists such as Mr. Gazzaniga, we must be cautious about making any quick conclusions about something that is very difficult to quantify and understand, even though it is something we all apparently have.Discussion of several other important topics is also strikingly lacking, in particular the process of forgiveness, religious and spiritual ideas, and the ability to experience altered states of consciousness. These all also appear to be uniquely human phenomena, and all also relate to Mr. Gazzaniga’s primary contention that the social environment is critically important in the development of the human brain. However, as research into spirituality and altered states of consciousness grows, it may be difficult to consider the human brain as purely a result of social influence. There is some basis for the social explanation of religion from an evolutionary perspective, but most religious and spiritual experiences occur on an individual level before they are ultimately translated to the group level. This, then, is a clear case in which we should consider the mutual influence of the brain on its social environment, rather than casually attributing complex phenomena to a simple social cause.Overall, however, “Human” offers a very thorough review of the current status of cognitive neuroscience and the fascinating future directions we may go in to unlock the mysteries of what makes us human. While Mr. Gazzaniga acknowledges that much still remains to be done, his book is also a rich testimony to the incredible accomplishments of the human brain in coming to understand itself.Mr. Newberg is an associate professor of radiology and psychiatry at the University of Pennsylvania, and the author of “Why We Believe What We Believe,” “Why God Won’t Go Away,” and “The Mystical Mind.”

The World Inside Our Heads: ‘Human’ by Michael Gazzaniga

The World Inside Our Heads: ‘Human’ by Michael Gazzaniga

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