Human: The Science Behind What Makes Your Brain Unique (2009) by Michael S. Gazzaniga
1. Opening Thoughts
2. Table of Contents
3. Further Reviews and Summaries
4. Quotes from the Book
Michael Gazzaniga is a well-respected researcher and writer. In this book he shares with us some of the recent discoveries of cognitive neuroscience in an easy to read and understand style.
We tend to believe the brain is fairly one dimensional. But what if the brain was made up of modules of neurons designed to perform certain tasks? What if we morality was hardwired? What if our brains are predisposed toward activity that relates so our social environment more than our individual choices?
These and other interesting questions are revealed in this easy to read book about your unique brain!
Table of Contents
Part One: THE BASICS OF HUMAN LIFE
1. Are Human Brains Unique?
2. Would a Chimp Make a Good Date?
Part Two: NAVIGATING THE SOCIAL WORLD
3. Big Brains and Expanding Social Relationships
4. The Moral Compass Within
5. I Feel Your Pain
Part Three: THE GLORY OF BEING HUMAN
6. What's Up with the Arts?
7. We All Act like Dualists
8. Is Anybody There?
Part Four: BEYOND CURRENT CONSTRAINTS
9. Who Needs Flesh?
Reviews and Summaries
Quotes from the Book (location is based on Kindle edition of the book)
The neocortex is the evolutionarily newer region of the cerebral cortex and is where sensory perception, generation of motor commands, spatial reasoning, conscious thought, and, in us Homo sapiens, language take place. The neocortex is divided anatomically into four lobes—the frontal lobe and three posterior lobes—the parietal, the temporal, and the occipital. Everyone agrees Read more at location 306 •
Gossiping has a bad reputation, but researchers who study gossip have not only found it to be universal,37 they have found that it is beneficial, that it is the way we learn to live in society. Dunbar thinks gossip is the human equivalent of social grooming in other primates (and remember, the size of the grooming group correlates with relative brain size). Read more at location 1550 •
Other studies show that two-thirds of the content of conversations are self-disclosure. Of these, 11 percent are about states of mind (my mother-in-law is driving me nuts) or body (I really want that liposuction). The rest are about preferences (“I know it’s weird, but I really like LA”), plans (“I am going to start exercising on Friday”), and the most talked about, doings (“I fired him yesterday”). In fact doings is the biggest category of conversations about others.42 Gossip serves many purposes in society: It fosters relationships between gossip partners,43 satisfies the need to belong and be accepted by a unique group,37 elicits information,44 builds reputations (both good and bad),43 maintains and reinforces social norms,45 and allows individuals to evaluate themselves through comparison with others. It may enhance status in a group, or it may just entertain.46 Gossip allows people to express their opinions, ask advice, and express approval and disapproval. Jonathan Haidt, a psychologist at the University of Virginia who studies happiness, writes that “Gossip is a policeman and a teacher. Without it, there would be chaos and ignorance.”47 Read more at location 1574 •
Evolutionary psychologists explain that a brain, at least in part, is made up of modules, which have developed specific functional purposes that are innate and have been selected for. Read more at location 1607 •
Leda Cosmides, one of the first in this field, describes the search for these functions: When evolutionary psychologists refer to “the mind,” they mean the set of information-processing devices, embodied in the human brain, that are responsible for all conscious and nonconscious mental activity, and that generate all behavior. What Read more at location 1609 •
Our minds should have programs that make us good at solving these problems, whether or not they are important in the modern world.50 Read more at location 1615 •
Paul Ekman, at the University of California, San Francisco, has done more for the study of facial expression than anyone else. Read more at location 1703 •
Ekman, through years of research, has established that facial expressions are universal67 and that there are specific expressions for specific emotions. When an individual is lying, the higher the stakes are, the more emotions (such as anxiety or fear) he is feeling.68 These emotions are leaked to the face69 and voice tone.70 And here is one of the benefits of true self-deception: If you don’t know you are lying, your facial expressions won’t give you away. Read more at location 1705 •
But our conscious, rational brain does not know that all this is going on. Our conscious brain works on a “need to know” basis, and all it needs to know is that siblings are having sex and that is bad. When you are asked, “Why is it bad?” things get interesting. Now you Read more at location 1939 •
Another factor that we seem to understand intuitively is intent in social exchange. That means if someone doesn’t reciprocate in a social exchange by accident, it is not recognized as cheating, but if someone intentionally does not reciprocate, it is recognized. Three- and four-year-old Read more at location 1953 •
Elliot could no longer function in a socially accepted way. He had a difficult time making appropriate decisions, and Damasio hypothesized that the reason was that he no longer had emotions. He proposed that before we make a decision, when an option presents itself, an emotional response is evoked. If it is a negative emotion, the option is eliminated from consideration before rational analysis begins. Damasio proposed that emotions play a major role in decision making, and that the fully rational brain is not a complete brain. Read more at location 1991 •
The interesting and scary thing is that your brain can think consciously about only one thing at a time. All those other decisions are being made automatically. There are two types of automatic processes. Driving is an example of intentional (you have the intention of driving to work) and goal-directed (get to work on time) processes that have been learned over time until they become automatic; so is playing the piano or riding a bicycle. The second type is preconscious processing of perceptual events: You perceive a stimulus by seeing, hearing, smelling, or touching, and your brain processes it before your conscious mind is aware that you have perceived it. This takes place effortlessly and without intention or awareness. It turns out that what this automatic processing is doing is placing all your perceptions on a negative (the room is white, I don’t like white) to positive (the room is brightly colored, I like bright colors) scale and biasing your decisions one way (something about this place isn’t calling to me…let’s keep looking) or the other (I bet this place is good, let’s eat here). Your automatic processing is helping you to answer the evolutionarily significant question, “Should I approach or avoid?” This is called affective priming, and it affects your behavior. If I asked why you don’t want to eat at the first place, you will give a reason, but it most likely won’t be “I get a negative flash in a white room.” It would more likely be “Oh, it just didn’t look all that exciting.” John Bargh at New York Read more at location 2002 •
Error management theory predicts that one should be biased toward committing errors that are less costly.14 In thinking about evolution, one would postulate that those who survived were those who reacted more quickly, that is, automatically, to a negative cue, and a negativity bias should have been selected for. After Read more at location 2023 •
Well, we do have a negativity bias! Big time. Subjects will pick angry faces out of a neutral crowd faster than happy faces.15 One cockroach or worm will spoil a good plate of food, but a delicious meal sitting on top of a pile of worms will not make the worms edible. And extremely immoral acts have an almost indelible negative effect: Psychology undergraduate students were asked how many lives a person would have to save, each on individual occasions and each at risk to his or her own life, to be forgiven for the murder of one. Their median response was twenty-five.16 This negativity bias has Read more at location 2027 •
Rozin and Royzman have suggested that the adaptive value of the negativity bias has four components: Negative events are potent. You can be killed! Negative events are complex. Should you run, fight, freeze, or hide? Negative events can happen suddenly. There’s a snake! There’s a lion! And they need to be dealt with quickly—a good reason that faster automatic processing would have been selected for. Negative events can be contagious—spoiled food, dead bodies, sick people. Read more at location 2036 •
THE NEUROBIOLOGY OF MORAL JUDGMENTS Now try this scenario, known as the trolley dilemma: A runaway trolley is headed for five people, who will be killed if it proceeds on its present course. The only way to save them is to hit a switch that will turn the trolley onto an alternate set of tracks Read more at location 2064 •
ACTION VERSUS NO ACTION We began by observing that we can make a moral judgment quickly, automatically. Even though we may not be able to explain it logically, we will keep on trying. In incest avoidance, we saw an example of hardwired behavior that we consider moral. In the trolley dilemma, we have seen that moral judgments are not completely rational. They depend on the circumstances (automatic bias, personal or impersonal situations). They depend on whether action or no action is required. They also depend on intent and emotions (Damasio’s patient Elliot). We have found that some automatic pathways are learned over time (driving), and some are inherent (approach-avoidance with a negativity bias). The latter can be affected by emotions, which also have been hardwired to varying degrees. Now we need to know a bit more about how the brain works. Read more at location 2095 •
It appears our brains have neuronal circuits that have developed over evolutionary time that do indeed do specific jobs. Read more at location 2105 •
The concept of a brain with specialized circuits for specific problems is Read more at location 2106 •
And nowhere were such phenomena more dramatic than in split-brain patients, proving that the left side of the brain is specialized for one set of capacities and the right Read more at location 2109 •
More recently, the idea of modularity has been augmented by evolutionary psychologists. Cosmides and Tooby, for example, define modules as “units of mental processing that evolved in response to selection pressures.” Read more at location 2111 •
Modern brain imaging studies have shown that the circuits for these modules can be widely scattered. And modules are defined by what they do with information, not by the information they receive (the input or stimulus that triggers them). Read more at location 2113 •
Clearly, over evolutionary time, these modules evolved to react in specific ways to specific stimuli in the environment. Read more at location 2115 •
More types of information are going in, but the modules are still triggered in the same old ways. Although the range of stimuli is broader, their Read more at location 2116 •
The brain is basically lazy. It will do the least amount of work it can. Because using intuitive modules is easy and fast and requires the least amount of work, that is the default mode of the brain. Read more at location 2122 •
The proposal is that a stimulus induces an automatic process of approval (approach) or disapproval (avoid), which may lead to a full-on emotional state. The emotional state produces a moral intuition that may motivate an individual to action. Reasoning about the judgment or action comes afterward, as the brain seeks a rational explanation for an automatic reaction it has no clue about. This Read more at location 2131 •
Marc Hauser points out that there are three possible scenarios for intuitive processes. At one end of the spectrum of opinion are those who believe there are specific inborn moral rules: It is wrong to kill, steal, or cheat; it is good to help, be fair, and keep promises. On the opposite end of the argument, some maintain that we are born with no intuitions, just the proverbial blank slate, an ability to learn moral rules. Read more at location 2135 •