This (somewhat long) article is the second in a series of six articles.
Preview. 1. A New Science.

When we judge whether we like or dislike a work of art, we're making a decision. To truly understand how to measure art, we need to understand how the brain makes decisions.

In his book The Metaphysical Club, Louis Menand describes an observation Oliver Wendell Holmes made about our legal system. Even though our legal system is set up to make decisions like this:

1. gather facts
2. analyze facts
3. make the decision

it seemed that most of the time, judges actually did this:

1. make the decision
2. gather facts that support the decision
3. present analysis to explain decision

People made their decisions first! How could they make their decisions before they had seen the facts? What, Holmes wondered, did they base their decisions on? Practical experience, Holmes decided.

(Holmes then went on to make some quite illogical decisions based on his own practical experience, including ruling that professional baseball should be exempt from anti-trust laws.)

Daniel Kahneman won the 2002 Nobel Prize for Economics. His studies have focused on how people make economic choices. Kahneman and others have found that people have two decision-making systems. One system is intuitive, the other is rational. From an interview in Strategy+Business (registration required, emphasis mine):

There are some thoughts that come to mind on their own; most thinking is really like that, most of the time. That's System 1. It's not like we're on automatic pilot, but we respond to the world in ways that we're not conscious of, that we don't control. The operations of System 1 are fast, effortless, associative, and often emotionally charged; they're also governed by habit, so they're difficult either to modify or to control.

There is another system, System 2, which is the reasoning system. It's conscious, it's deliberate; it's slower, serial, effortful, and deliberately controlled, but it can follow rules. The difference in effort provides the most useful indicator of whether a given mental process should be assigned to System 1 or System 2.

Kahneman tried to train people to make decisions using their rational system in instead of their intuitive system. But the effort was fairly futile:

Our research doesn't say that decision makers can't be rational or won't be rational. It says that even people who are explicitly trained to bring System 2 thinking to problems don't do so, even when they know they should.

In other words, he found the same thing Holmes did: that people have an extremely strong tendency to judge first, then reason later.

A just machine to make big decisions
Programmed by fellows with compassion and vision
We'll be clean when their work is done
We'll be eternally free yes and eternally young
--I.G.Y, Donald Fagen

Humans appear designed for inefficiency. Judges make decisions before they consider the evidence. Businessmen ignore logic and opt for less-than-optimal economic choices. Perhaps the song I quoted above is correct. We'd be better off having some kind of android making our decisions for us.

The perplexing thing is that each of us already has an android-like system for making decisions within us: Kahneman's System 2. Let's call this system Android Brain.

Android Brain does things methodically, in sequence, and follows rules to arrive at logical conclusions. You can give Android Brain step-by-step instructions, and it will follow those instructions. It's programmable. It's available to use. So why do we ignore it? Why do we so strongly prefer the intuitive system that is more error-prone? Are we designed wrong?

Not really. There's a very good reason we do this.

Quick, tell me exactly what you do with your left big toe when you walk.

Don't know? Well, actually, you do know. If you didn't know, you couldn't walk. So how come you can't tell me?

Well, just as there are two reasoning systems in the brain, there are two memory systems, too. Scientists call the two types of memory declarative and nondeclarative.

Declarative memory is what we usually think of when we think of memory. It is our conscious memory. It contains facts and events. When it fails, such as in Alzheimer's Disease, we lose our ability to remember what happened in our lives. Declarative memory is strongly associated with Android Brain, our reasoning system. Its processing center is an area of the brain called the hippocampus.

Sometimes called procedural memory, our nondeclarative memory is often overlooked because these memories are not conscious. They hold things like motor skills and habitual behavior. The reason you can't tell me what your left toe does when you walk is because this is a nondeclarative memory. Your conscious mind does not have any access to this data. The processing center for nondeclarative memory is an area of the brain called the amygdala (a-MIG-da-la).

The amygdala has a second purpose besides handling your nondeclarative memories. It's also the central processing center for your emotions. When you're afraid, angry, excited, or happy, that's your amygdala talking. The fact that the amygdala handles both your motor skills and your emotions is significant.

Imagine you're a zebra, grazing on the savannahs of Africa. There's a light breeze blowing the tall grass around. Suddenly, you notice a strange indentation in the grass. You feel fear, and in fear, you jump up and run away. A good thing you did, too, because that indentation was a lion sneaking up on you.

This is Kahneman's System 1 in action. Let's call this system Animal Brain.

Animal Brain has a tight coupling between emotions and motor skills. It's an effective architecture, because quicker you react to danger, the more likely you'll stay alive.

Animal Brain did three things to save your life:

1. It recognized an unusual pattern in your environment
2. The recognition caused an emotional reaction
3. The emotional reaction triggered a habitual, physical behavior

Because you were able to recognize this pattern and react to it in an instant, you are still alive.

This is why we have a strong preference for the decisions of Animal Brain over Android Brain. Any ancestor who favored using the slower, rational decision system of a Android Brain was more likely to be eaten by lions. The ones who preferred the quick decisions of Animal Brain stayed alive to pass their genes on to you.

So how did our imagined zebra know the difference between the motion of the grass caused by the wind, and that caused by the lion? Let's take a slight detour and look at memory.

The process for creating Android Brain's declarative memories is pretty complex. Animal Brain's nondeclarative memories are more primitive and easy to explain.

In 1949, a scientist named Donald O. Hebb proposed a theory about how learning works in the brain. All learning, whatever the senses involved, uses the same basic mechanism: pairs of neurons firing together.

Fifty years later, a 1999 study out of Princeton University led by neurobiologist Joe Tsien revealed the genetic mechanism for Hebb's rule. The gene, called NR2B, creates a protein which acts like a double lock on a door:

It needs two keys -- or two signals -- before it opens. As such, it is an excellent tool for creating memory, a process that fundamentally consists of associating two events. If two signals arrive at the same time -- maybe one results from seeing a lit match and the other results from a sensation of pain -- then the receptor is triggered and a memory is formed.

Animal Brain memories are altered by various forms of conditioning: repeated exposure to stimuli in the environment. The most famous example of conditioning is Pavlov's dog. The dog drooled when he heard a bell, because he had been conditioned to expect food after a bell rang.

One form of conditioning is called habituation. In the book Memory: From Mind to Molecules, authors Larry Squire and Eric Kandel describe it like this:

...habituation is learning to recognize, and ignore as familiar, unimportant stimuli that are monotonously repetitive. Thus city dwellers may scarcely notice the noise of traffic at home but may be awakened by the chirping of crickets in the country.

When we're first exposed to something new, a new memory is formed. If we are repeatedly exposed to it, though, and it proves harmless, we get conditioned to ignore it.

Thus, a zebra who is repeatedly exposed to the pattern of grass waving in the wind will become conditioned to ignore it. However, a change to that pattern could indeed have alarming consequences: it could be a lion. The zebra won't ignore that stimulus.

Now, back to the two brain systems. Let's compare them:

	Animal Brain	Android Brain
science term	System 1	System 2
reasoning	instinctual	rational
speed	fast	slow
awareness	subconscious	conscious
reactions	automatic	deliberate
effort	effortless	effortful
memory type	nondeclarative	declarative
memory content	patterns, motor skills, habits	facts, events
processor	amygdala	hippocampus

The reasoning skills of our Android Brain seems rather unique to humans, although other mammals do have declarative memories. It should be obvious that all mammals, if not all animals, have a brain system that works more or less like Animal Brain.

Although the human Animal Brain shares many things in common with a zebra's, they are not identical. Humans have evolved some very important differences.

At the Neuroesthetics conference I went to, Dan Fessler, an anthropology professor from UCLA, gave a presentation about shame and pride, two uniquely human emotions. These emotions depend on the ability to imagine what someone else is thinking. For example, you don't feel ashamed if you're alone and you discover your fly is open. You only feel ashamed if you know that someone else knows that your fly is open.

But by far the most important difference between a human's Animal Brain and a zebra's is language. Language is a function of our Animal Brain: it is an automatic and subconscious skill. We speak and understand without deliberate effort. It has a sophisticated type of pattern recognition (listening), and an associated motor skill (speaking).

What happens when the two systems need to interoperate? It was pointed out in the Neuroesthetics conference that the conversation is extremely one-sided. Animal Brain broadcasts all kind of information to Android Brain: emotions, sensations, decisions, language. But Animal Brain seems to be completely unaware that Android Brain even exists. Hardly any information at all flows in the other direction.

Remember, Animal Brain is designed to keep you alive and reproducing. From an evolutionary standpoint, nothing is more important than that. And Animal Brain knows it.

Frog and Toad ate one very last cookie.

"We must stop eating!" cried Toad as he ate another.

"Yes," said Frog, reaching for a cookie, "we need will power."

"What is will power?" asked Toad.

"Will power is trying hard not to do something that you really want to do," said Frog.

  --Arnold Lobel, Frog and Toad Together

In this delightful children's book, Frog and Toad have a problem. Their Animal Brains are telling them to eat more cookies. Their Android Brains are telling them not to. They are finding it extremely difficult to ignore their Animal Brains.

Animal Brain is like that guy you meet at a party that you can't get away from. He talks and talks and never listens to a word you say. If you try to ignore him, he STARTS TALKING LOUDER. If you try to turn away, he pulls you back: THIS IS IMPORTANT! DON'T MISS A WORD! You have no choice but to humor him.

Animal Brain: what a jerk.

Now, if his message is "there's a lion sneaking up on you," you're grateful for his message. But if you're on a diet, and he keeps telling you "EAT ANOTHER COOKIE", it would be better to ignore his message. But it's very hard to do so. He's so insistent! Animal Brain assumes everything is urgent. Every situation is life or death.

How do you handle a jerk like that?

Well, one way is to use your own strengths. One of Android Brain's strengths is the ability to follow rules. So we come up with rules that help us manage the behavior of Animal Brain and correct its errors: Ten Commandments, Twelve-Step Programs, Seven Effective Habits, that sort of thing.

Another way is to exploit his weaknesses. And Animal Brain does have weaknesses. That's where art comes in.

Next: Hypothesis