Goodhart’s Law and Emotions

When a measure becomes a target, it ceases to be a good measure.

— Marilyn Strathern

Goodhart’s law is an important principle about using a measure to drive action.

Imagine a city that is trying to reduce crime. The mayor tells the police chief to “Get the crime rate down!”. But what is the crime rate? It is a statistical metric of crimes per capita. The police measure the crime rate by making reports about crimes. Knowing that his job is on the line, the police chief tells his officers to go easy on crime reports. “Don’t file a report unless it is serious.” he tells them. So, the crime rate (as measured) goes down, while the actual number of crimes goes up, because criminals learn that they are less likely to be punished, and citizens learn that there is no point calling the police over minor crimes.

Eventually, word gets back to the mayor, and he fires the police chief. He hires a new police chief, and gives him a different instruction. “I want to see more arrests!” So, the new police chief tells his officers to arrest more criminals. In fact, he gives them a quota for arrests. The police officers naturally go looking for criminals — but not the most serious criminals who commit the worst offenses. Instead, they prioritize criminals who are easy to arrest. They fill their quotas with jaywalkers, loiterers, minor drug users, etc. Meanwhile, serious crime increases. Also, the courts dismiss many of the cases brought before them, as frivolous. The arrest rate goes up, but the conviction rate goes down.

I could continue with the story, but hopefully you get the idea. Crime is a complex social issue. The problem of crime, and thus the job of law enforcement, cannot be reduced to a single measure. Also, a measure that is a useful approximation to the severity of the crime problem, such as the crime rate or arrest rate, becomes less meaningful when it is targeted, because there is a tendency to game the measure. Instead of targeting crime itself, the police force starts targeting the measure. That makes the measure less accurate as a representation of the underlying problem.

There are many other examples of Goodhart’s law and its importance in human affairs.

Now, let’s consider an absurd example. Suppose that we are concerned with the efficiency of a car. We measure the distance traveled with an odometer, and we are trying to maximize the miles per gallon (or kilometers per liter) of the car. Some clever person discovers a way to improve the efficiency by a factor of 10: put the car up on blocks, so the wheels don’t touch the ground. Without the friction of the road surface, without air friction, without the need to accelerate the car’s mass from stops or around turns, the efficiency increases by a huge amount, as measured by the odometer and gas consumption.

This is absurd, of course, because it completely negates the purpose of the car, which is to move people and cargo around on roads. The odometer is a measure of the rotation of the wheels, not the distance traveled by the car. Under normal use, the former is a good way to measure the latter. But if we put the car up on blocks, the causal relationship between them disappears.

Goodhart’s law applies to human desire in the modern environment. In the ancestral environment, desire was a good measure of adaptiveness. Most of the time, people wanted what was biologically good for them. Today, we can put ourselves “up on blocks” with modern technology, so that our emotional wheels spin faster without resistance. Desire has ceased to be a good measure of adaptiveness.

Desire (motivation) is ultimately generated by the emotions. The brain has a motivation mechanism, which contains a number of different drives/emotions. Each emotion has a biological function: to motivate a certain type of behavior. Hunger makes us eat. Thirst makes us drink. Fatigue makes us rest. Lust makes us have sex. Each type of behavior solves a biological problem. Each problem is ultimately instrumental to reproduction.

Emotions are a crude mechanism. They are heuristic, ad hoc and stimulus-dependent. They do not directly measure the adaptiveness of an action. They do not work in every situation. They can be deceived by artificial stimuli.

Some emotions, such as hunger and thirst, are tied to bodily states, and so they reflect adaptiveness pretty well, although not perfectly. Some people eat too much food, because we are more adapted to food scarcity than food abundance. But hunger works pretty well, even in the modern environment.

Some emotions depend on external stimuli. For example, lust depends on the appearance of another person. That information has to be acquired through vision, and then processed in the brain. Sexual arousal can be produced by a fake stimulus, such as an image of a naked woman.

Although emotions are not a direct measure of adaptiveness, they evolved to motivate adaptive behavior, and thus motivation is essentially a proxy for what is adaptive in the current situation. Action is driven by motivation, and thus action “targets” reducing motivation. This is analogous to the police targeting the crime rate. Our brains are targeting a measure that they internally generate.

Of course, the brain doesn’t choose what our emotions are. Emotions are built into the structure of the brain, and emotions evolved. But if we just act to reduce motivation (and thus to make ourselves feel good), we could end up gaming our emotions. We could find ways of feeling good that are not adaptive.

The most obvious way of gaming our emotions is with opiate drugs. Opiate drugs directly reduce motivation, and thus generate pleasure. The opiate addict puts most of his thought and effort into obtaining the drug, rather than doing the things that his emotions evolved to make him do.

We can game our emotions with artificial stimuli, such as video games and porn. We can use artificial stimuli to create the same emotional states that real stimuli would cause, but without adaptive behavior.

We can also game our emotions with birth control, which makes sex into an artificial stimulus. Sex with birth control is just a way to manipulate emotions. It is no longer adaptive, because its biological function has been eliminated.

People who use birth control have the emotional experiences that are associated with real sex: arousal, satisfaction, love, etc. However, those emotional responses are detached from their biological functions: finding a mate, procreating and creating a pair-bond to raise a child. The person has detached themselves from their biological purpose of reproduction. Like putting the car up on blocks, this makes it easier to go through emotional cycles, but the cycles do not drive the person toward reproduction.

Opiate drugs, video games and birth control are all analogous to putting the car up on blocks. The wheels spin, but the car goes nowhere. The person goes through emotional cycles without making biological progress.

In modern civilization, we are gaming our emotions, making them a terrible measure of adaptiveness. This is due to hedonism and modern technology. Hedonism recognizes no higher purpose than emotional experience. Modern technology allows us to target emotional experience in new ways.

Hedonism inverts the functional relationship between motivation and action. Biologically, motivation is instrumental to action, and action is instrumental to reproduction. Emotional experience (pain and pleasure) is not the purpose of life. It is the experience of changing motivation, and the function of motivation is to generate action toward life’s purpose. To the hedonist, however, emotional experience is the ultimate source of value. Action is instrumental to lowering motivation, which is experienced as pleasure.

The “pursuit of happiness” does not generate adaptive behavior in the modern environment. Instead, it generates maladaptive behavior. (It doesn’t generate happiness either, but that’s another story. See Motivation.)

Imagine if the engineer viewed increasing the odometer number as the purpose of the car, and the movement of the car on the road as just a way to increase that number. He would view putting the car up on blocks as progress.

That is what modern man is doing with respect to emotions and adaptiveness. He is spinning his emotional wheels and going nowhere.