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 the arrest rate, becomes less meaningful when it is targeted, because there is a tendency to game the measure. Rather than targeting the real problem, the police start targeting the measure, which makes the measure less accurate as a representation of the real 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.

See Motivation.

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, 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 is 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 do not directly measure adaptiveness, they evolved to motivate adaptive behavior. 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.

Because motivation is a crude proxy for adaptiveness, actions that reduce motivation are not always adaptive. Emotions can be deceived.

Opiate drugs deceive emotions chemically. 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 deceive 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 deceive 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.

A user of birth control has 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. Birth control detaches a person from his biological purpose.

This is analogous to putting a car up on blocks. The wheels spin, but the car goes nowhere. The car has been detached from the road, and thus from its purpose. Opiate drugs, video games and birth control detach emotions from their biological functions. The emotional wheels spin faster without resistance, but the person goes nowhere, biologically.

Modern human behavior is very maladaptive. The most obvious example is the low fertility of people in advanced societies. Rather than acting toward the biological purpose of reproduction, people are using modern technology to deceive their emotions.

Hedonism is part of the problem. Hedonism is the belief that pleasure is intrinsically good, pain is intrinsically bad, and nothing else is intrinsically good or bad. It is a theory of personal value (what is good | bad for the self). Our culture assumes hedonism implicitly. It recognizes no higher purpose than the pursuit of happiness. To a hedonist, emotional experience is the target, not just a crude measure of something else.

Hedonism inverts the functional relationship between motivation and action. Biologically, motivation is instrumental to action, and action is instrumental to reproduction. We feel in order to act, and we act in order to reproduce. To the hedonist, we act to change how we feel, and feelings are intrinsically valuable.

You can’t catch happiness by pursuing it, but that’s another story. See How I Rejected Hedonism.

Imagine an engineer who believes that the purpose of a car is to increase the odometer number, and the movement of the car on the road is merely instrumental to that purpose. He would view putting the car up on blocks as progress.

In the modern environment, the pursuit of happiness is maladaptive, because we can deceive our emotions artificially. We can spin our emotional wheels more efficiently by detaching them from their biological functions. Modern man is spinning his emotional wheels at a furious pace, but going nowhere.