Human: The Science Behind What Makes Us Unique,   ISBN:9780060892883

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In Human, Dr. Michael S. Gazzaniga provides us with a detailed (almost to a fault at times) examination of the human brain. Although I wouldn't recommend it for anyone without at least rudimentary knowledge of brain anatomy and function, it provides an enlightening and humbling look at just what exists inside our heads that makes us so dramatically different from every other species on Earth.

My tendency to devour science fiction books while pretty much ignoring the world of non-fiction had me apprehensive about reading such a lengthy and in depth work of legitimate science, but I found myself pleasantly surprised (and at times enthralled) by the many facets of this book and how well they blend together. Gazzaniga has mastered the art of keeping lengthy anatomical dissertations interesting by linking them with thought-provoking experiments and case-studies, all the while inserting chuckle-inducing one-liners and quips.

The book is laid out in four parts, with each part being around 100 pages long and consisting of two to three chapters apiece. Within the chapters are titled subsections that help keep the countless ideas and transitions neatly organized. Footnotes and citations abound throughout the book, and the last fifty or so pages consist of bibliographical notes and an index.

The first of the four parts is called The Basics of Human Life, which begins with Chapter 1: Are Human Brains Unique? In this chapter, Gazzaniga begins with a discussion of the basic anatomy of the brain, including size, regions and structures. He explains lateralization and cortical columns in a fair amount of detail, and begins showing how the human brain is physically different from the brains of other primates. This chapter may seem boring for readers, but it provides a good introduction to the human brain which is necessary for understanding the later observations of the book.

The next chapter begs the question of whether a chimp would be a good date, and it begins to delve deeper into the mental capacity and characteristics exhibited by humans and other primates. Gazzaniga immediately discusses the tendency of humans to personify other animals, and cautions against using that tendency to interpret the actions of chimpanzees and other animals in lieu of a purely scientific approach. He briefly touches on the genomic differences between humans and chimps before beginning a discussion on the physical similarities and differences between the two species, and how each species came to evolve these characteristics. The discussion soon leads to mental differences, including the use of language and theory of mind. Gazzaniga describes the areas of the brain responsible for these characteristics, and how the relative size of these regions differs greatly between the two species. Gazzaniga concludes that "a day spent with [a chimpanzee] would be very interesting," but he would "prefer more culture" (75).

Part 2 - Navigating the Social World - begins with a chapter called Big Brains and Expanding Social Relationships. In this chapter, Gazzaniga discusses the evolutionary origins and positive selection of social groups. The discussions regarding the evolutionary benefits and origins of gossip and intentional lying were particularly interesting and humorous.
The next chapter highlights the presence of morals in human culture and how our brain incorporates both moral inclinations and rational thought into the decision making process. An in depth illustration of the evolutionary development and advantages of the five "moral modules" - reciprocity, suffering, hierarchy, coalition, and purity - explains that all human virtues originated from one or more of these five modules (132). The chapter closes by mentioning that the rational and emotional parts of our minds often conflict with one another, but unconscious mental processes influence our decisions also.

The fifth chapter, called I Feel Your Pain, illustrates many examples of subconscious imitation and mimicry between humans, such as wincing when seeing another human in pain. Discussions of mirror neurons and their involvement in unconscious empathetic responses were very illuminating. The chapter continues on to mention conscious displays or suppression of emotion, and ends by touching on self-awareness and its importance in filtering automatic empathetic responses to distinguish between experienced and observed harm.

Part three (The Glory of Being Human) begins with the sixth chapter, entitled What's Up with the Arts. This chapter details the evolutionary roots and fitness benefits of art and music, which I found to be quite interesting. In addition to art and music, aesthetics and human ideals of beauty are shown to have fitness benefits that are purely biological, including sexual preferences for symmetry, which subconsciously suggests physical fitness.

Chapter seven examines the tendency of humans to emphasize the belief of duality of mind and body. This section struck me as unnecessarily lengthy and philosophical, though not without a few interesting points, such as the power of human intuition with regards to physics and the benefits and fallacies humans owe to their theory of mind.

The eight chapter, Is Anybody There, discusses in depth the specific regions and characteristics of the brain that allow humans to experience consciousness and self awareness. This chapter has a great deal of information about people whose brains have been injured and the effects of such injuries on their personalities or mental/physical functioning. Gazzaniga concludes with the statement that "consciousness is an emergent property and not a process in and of itself" (320).

As a fanatical science fiction reader and biomedical engineer, the last chapter (Who Needs Flesh) was the most interesting in the book. It describes the advances being made in neuroscience and what we have to look forward to from the future. Discussions of brain-computer interfacing, AI development, genetic modification, and medical device implantation were very in-depth and interesting. Detailed explanations of recent scientific advances should leave any reader anticipating the near future with optimism and excitement.

All in all, I'd say that Human is a very enlightening read for anyone interested in neuroscience or human evolution. It has definitely given me a new respect for the human brain, and maybe even an idea or two for a new science fiction story.

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Human: The Science Behind What Makes Us Unique
Michael Gazzaniga serves up a feast for those interested in the brain sciences and human evolution. He covers the evolution of the brain, how humans differ from other primates, the role of the brain in social relationships, innate aspects of morality, how we sense the feelings of others, possible evolutionary components of our aesthetic propensities, intuitional shortcuts that help us get on in the world, the nature of consciousness, and actual and potential technical alterations of our biologically inherited capacities.

He summarizes hundreds of scientific studies in a style for the most part digestible for lay readers, although you may need to employ a good proportion of your one hundred trillion synaptical connections to keep up. His presentation is well-organized, broken into comprehensible topics and sub-topics typically just a few pages each in length. He frames questions in a manner that both provokes curiosity and illuminates the study findings he reports (for instance, "Do animals have a moral sense?"). Sometimes he is lightly humorous (such as when he creates a fictitious personals ad written by a chimpanzee) and he readily relates the issues and the science to our experiences (why do you feel my pain when you see me smash my finger in a car door, for example?). Unfortunately, there are no illustrations; a few would have been useful to help readers better picture the brain anatomy that he frequently references.

When the rational self steps in and informs behavior that is a uniquely human moment, Gazzaniga says. However, like many others writing in a similar vein in the past several years, he underscores the bounds of human rationality. When we make decisions reason may list the options, but our emotions make the choice.

For those not already immersed in this literature this book can serve as a very good introduction. And Gazzaniga covers such a wide swath of the research that even knowledgeable readers are likely to find sufficient novelties to fire-up at least a few new synapses.

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Let me say that my review is quite biased. I'm not offering an opinion (wouldn't be qualified anyway) on the quality of the scientific information presented, nor even on the author's ability to present it - even though I picked it up because I do have an interest in the subject. I give the book one star only for the self-absorbed reason that I was so immediately turned off by the author's attitude that I decided rather quickly not to continue reading it.

Gazzaniga is very open about his own bias in his prologue: "I love our species, and always have. I have never found it necessary to lessen our success and domination of this universe." Fair enough, and certainly helpful to the reader for the author to state his perspective so plainly. But unfortunately his statement has very concrete applications. From chapter 2:

"There isn't a human being on earth who does not look at his or her dog or cat ... without an irrational reverence and fondness."

Irrational fondness? Does he really mean that? Indeed he does. "Our species has had a hard time drawing the line between us and them." Even the author, he has to admit, suffers this irrationality on occasion:

"I have carried out extensive animal primate research. ... The research frequently required carrying out major neurosurgical procedures, and in some instances, major efforts were necessary for their postoperative care. I found each one taxing and troubling."

Taxing and troubling. Poor man. Even he, a man of science, is susceptible to these irrational feelings of empathy. How silly of him to feel "pity" for a fellow primate - a completely healthy and innocent individual - that he has just performed brain surgery on for the purpose of furthering human knowledge. How misplaced that pity - how childish and impractical! Better wipe away those feelings lest we start finding it necessary to question our state of domination. But he can snap himself out of it. After all, the author jokes, "would I want to spend a lot of time with a chimp?"

I didn't read any further.

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Much has been written lately about the continuity between other animals and humans and Gazzaniga, partly in response, focuses on what is particularly "human" about us and how we differ fundamentally even from our closest relatives among the primates. The book is filled with studies about the brain, cognition, and related topics that are intriguing and amusing as well as informative. Gazzaniga's scientificaly detailed but at the same time colloquial style makes it enjoyable reading. I've learned from it a lot that I wanted to know.

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My dog, Shadow, does not have an intact disgust module. Neither did the succession of best friends who preceded him: Isabella, Charlotte, Karma, or "99." Dogs will eat or roll in practically anything, and show no sensitivity to an emotion that seems to be uniquely human. Human infants don't have it until they're five to seven years old.

Disgust is one of the five emotional modules that distinguish humans from other species. Other emotional modules are common across species, says Michael Gazzaniga, an eminent cognitive neuroscientist (and co-inventor of the field). Neither we, nor human infants, nor wallabies, for example, have to be explicitly taught to avoid certain dangers. Encountering a fast approaching, large something with sharp teeth - even if one has never encountered it before - causes an automatic fear and avoidance reaction. Evolution has hard-wired a general fear template into our brains, rather than a fear of specific things - you never know what you might encounter, and you don't want to sit there ruminating about it while you become lunch. Speaking of ruminating, part of what makes human brains special is that we are the only animals who even bother to ask the question of why we're special, or who worry about what others think.

Human makes a lively and fun tour through the latest research on brain evolution. (Full disclosure: three of my papers are mentioned in his book, out of the hundreds of studies discussed). The human brain turns out to be less different from other animal brains than you might think. Language and social cognition fall along a continuum across species. Deceiving others, for instance, long thought to be unique to humans, is present in monkeys and crows, who can even hide their attempts to deceive. Counterintuitively, much of what makes us human is not an ability to do more things, but an ability to inhibit automatic responses in favor of reasoned ones; consequently we may be the only species that engages in delayed gratification and impulse control (thank you pre-frontal cortex).

Gazzaniga doesn't shy away hard problems such as why there is art. The attraction to fictional experiences - stories, plays, paintings, and music - is puzzling from an evolutionary perspective. "Why does the brain contain reward systems that make fictional experiences enjoyable?" Involvement with the imaginative arts, he observes, "is self-rewarding without an obvious functional payoff."

The answer is that fictional thinking engages innate "play" modules that enhance fitness by allowing us to consider possible alternatives - hypothetical scenarios - so that we can form plans in advance of dangers, hazards, or even unpleasant social scenarios. "It would be fitness enhancing to learn to hide or run from a predator, or stalk and search for food, before one actually needs to do it for survival." Amount of play, we learn, is correlated with species' brain size, and play is seen as practice for real life. "From having read the fictional story about the boy who cried wolf. . .we can remember what happened...and not have to learn that lesson the hard way in real life. The more fictional stories we hear, the more circumstances we become familiar with...The arts are not frosting but baking soda."

The controversial and hair-raising final chapter explores brain implants and germ-line gene therapy. It is one thing to accept interventions when future tests can detect cystic fibrosis or muscular dystrophy in a developing embryo, Gazzaniga notes. But we may soon identify genes that indicate a high probability of developing diabetes in middle age, or heart disease. Will we terminate the embryo and "start all over again, and try for a better one?" Or sneak inside and change offending genes merely because of their probabilistic tendencies?

The power of the last chapter is in its ability to cause one to rethink one's positions. Some may find the idea of a neural implant, a computer chip grafted to the brain to be, well, disgusting. But Gazzaniga artfully shows how the lines can become blurred. We already alter our neurochemistry through caffeine and alcohol (not to mention Prozac). People with thyroid or pituitary problems take pills or daily injections to restore their hormonal balance. Others wear cochlear implants or electrodes to stimulate parts of the brain that are injured. If these technologies were combined - if a chip could mediate thyroid function - that doesn't seem radically different from an injection. Or a neural implant may more conveniently stimulate the pre-frontal cortex and brain stem the way that caffeine or Ritalin or Prozac do. Will we accept an implanted memory restorer for people with Alzheimer's? What about schoolchildren, Gazzaniga asks: "Honey, I know that we were saving this money for a vacation, but maybe we should get the twins neural chips instead. It is hard for them in school when so many of the other kids have them. . ." But if this is fundamentally different from discussions in previous generations about buying glasses, hearing aids, or paying for Ritalin, that difference is not obvious. If a neural implant could keep Shadow from rolling in dead squirrel (and pilfering countertop cake and cookies) maybe it's not so disgusting after all.


Daniel J. Levitin is a Professor of Psychology and Behavioral Neuroscience at McGill University, and is the author of the New York Times bestsellers This Is Your Brain on Music This Is Your Brain on Music: The Science of a Human Obsession and The World in Six Songs: How the Musical Brain Created Human Nature The World in Six Songs: How the Musical Brain Created Human Nature.