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
Opening Thoughts
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 •
