Tuesday, September 09, 2008

HUMAN - The Science Behind What Makes Us Unique

That is the title of the latest book by Michael S. Gazzaniga, a popular and lucid writer on the beauty and intricacy of the human brain, i.e., a neuroscientist who can write clearly. This book is sitting on my shelf awaiting some free time for me to read it.

The New York Times
recently reviewed the book:
My dog, Shadow, does not have an intact disgust module. Neither did the succession of best friends who preceded him. Dogs will eat or roll in practically anything, without any trace of an emotion that seems to be uniquely human. Human infants don’t show disgust until they’re 5 to 7 years old.

Disgust, Michael S. Gazzaniga argues in his new book, “Human,” is one of the five emotional modules that distinguish us from other species. Other modules are common across species. Neither adults, nor human infants nor wallabies, for example, have to be explicitly taught to avoid certain dangers. Encountering a large, fast-­approaching creature with sharp teeth — even if you have never encountered it before — causes an automatic fear and avoidance reaction. Evolution has hard-wired a general fear response 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 rumination, 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.

Gazzaniga, a cognitive neuroscientist at the University of California, Santa Barbara (and one of the inventors of the field), takes us on a lively tour through the latest research on brain evolution. (Full disclosure: the book discusses three of my papers, among hundreds by others.) Human brains turn out to be less different from other animal brains than you might think. Language and social cognition fall along a continuum across species. Deception, for instance, long thought to be unique to humans, is present in monkeys and crows, which can even hide their attempts to deceive. Counterintuitively, much of what makes us human is not an ability to do more things, Gazzaniga writes, 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, prefrontal cortex).

Gazzaniga doesn’t shy away from hard problems, like why humans, alone among species, have art. The attraction to stories, plays, paintings and music — experiences with no obvious evolutionary payoff — is puzzling. “Why does the brain contain reward systems that make fictional experiences enjoyable?” he asks. Part of the answer, he argues, is that fictional thinking engages innate “play” modules that enhance evolutionary fitness (that is, the ability to propagate one’s genes) by allowing us to consider possible alternatives — hypothetical situations — so that we can form plans in advance of dangers or even just unpleasant social situations.
Read the whole review.

Meanwhile, Powell's posted an interview with Gazzaniga that is quite entertaining.

Describe your latest project.
We humans are special. All of us solve problems effortlessly and routinely. When we approach a screen door with our hands full of bags of groceries we instantly know how to stick out our pinky and hook it around the door handle to open it up. The human mind is so generative and given to animation that we do things such as map agency on to almost anything, our pets, our old shoes, our cars, our world. It is as if we don't want to be alone up here at the top of the cognitive chain, the smartest things on earth. We want to see our dogs charm us, appeal to our emotions, imagine they too can suffer and have pity, love and hate and all the rest. We are a big deal and we are a little scared about it.

Thousands of scientists and philosophers over hundreds of years have either recognized this uniqueness of ours or have denied it and looked for the antecedents of everything human in other animals. In recent years clever scientists have found antecedents to all kinds of things that we had assumed were purely human constructions. We used to think that only humans had the ability to reflect on their own thoughts, possess what is called "meta-cognition". Well, think again. Two psychologists at the University of Georgia have shown that rats also have this ability. It turns out rats "know" what they don't know. Does that mean we should do away with our rat traps? I don't think so.

Everywhere I look I see tidbits of differences and one can always say a particular tidbit can be found in others aspects of biological life. For example, "Do flies sleep?" The short version of this story is that flies do sleep, just like we do and more importantly, flies express the same genes during sleep and awake hours that we do. Indeed, even protozoans sleep!

The point is that any human activity can be seemingly atomized. But to be swooned by such a fact is to miss the point of human experience. In this book, I wanted to comb though facts about our brains, our minds, our social world, our feelings, our artistic endeavors, our capacity to confer agency, our consciousness and indeed our growing knowledge that our brain parts can be replaced with silicon parts. From this jaunt one clear fact emerges. Although we are made up of the same chemicals, with the same physiological reactions, we are very different from other animals. Just as gases can become liquids, which can become solids, phase shifts occur, shifts so large in implications, it becomes almost impossible to think of a foggy mist being made up of the same stuff that makes up an iceberg. And yet the different substances have the same chemical structure. In a complex relationship with the environment, very similar stuff can become quite different in its reality and structure. Indeed, I have decided something like a phase shift has occurred in becoming human. There simply is no one thing that will ever account for our spectacular abilities, aspirations and capacity to travel mentally in time to almost the infinite world beyond our present existence. Even though we have all of these connections with the biologic world from which we came, and we have in some instances similar mental structures, we are hugely different. While most of our genes and brain architecture are held in common with animals, there are always differences to be found. And while we can use lathes to mill fine jewelry, and chimps can use stones to crack open nuts, the differences are light years apart. And while, the family dog may appear empathetic, no pet understands the difference between sorrow and pity.

A phase shift occurred and it occurred as the consequence of many things changing in our brains and minds. This book is the story of our uniqueness and how we got here. Personally, I love our species, and always have. I have never found it necessary to lessen our success and domination of this universe. So let us start the journey of understanding why humans are special and let's have some fun doing it.
Go read the whole interview.

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