Why it matters that torture is ineffective

JDN 2457531

Like “longest-ever-serving Speaker of the House sexually abuses teenagers” and “NSA spy program is trying to monitor the entire telephone and email system”, the news that the US government systematically tortures suspects is an egregious violation that goes to the highest levels of our government—that for some reason most Americans don’t particularly seem to care about.

The good news is that President Obama signed an executive order in 2009 banning torture domestically, reversing official policy under the Bush Administration, and then better yet in 2014 expanded the order to apply to all US interests worldwide. If this is properly enforced, perhaps our history of hypocrisy will finally be at its end. (Well, not if Trump wins…)

Yet as often seems to happen, there are two extremes in this debate and I think they’re both wrong.
The really disturbing side is “Torture works and we have to use it!” The preferred mode of argumentation for this is the “ticking time bomb scenario”, in which we have some urgent disaster to prevent (such as a nuclear bomb about to go off) and torture is the only way to stop it from happening. Surely then torture is justified? This argument may sound plausible, but as I’ll get to below, this is a lot like saying, “If aliens were attacking from outer space trying to wipe out humanity, nuclear bombs would probably be justified against them; therefore nuclear bombs are always justified and we can use them whenever we want.” If you can’t wait for my explanation, The Atlantic skewers the argument nicely.

Yet the opponents of torture have brought this sort of argument on themselves, by staking out a position so extreme as “It doesn’t matter if torture works! It’s wrong, wrong, wrong!” This kind of simplistic deontological reasoning is very appealing and intuitive to humans, because it casts the world into simple black-and-white categories. To show that this is not a strawman, here are several different people all making this same basic argument, that since torture is illegal and wrong it doesn’t matter if it works and there should be no further debate.

But the truth is, if it really were true that the only way to stop a nuclear bomb from leveling Los Angeles was to torture someone, it would be entirely justified—indeed obligatory—to torture that suspect and stop that nuclear bomb.

The problem with that argument is not just that this is not our usual scenario (though it certainly isn’t); it goes much deeper than that:

That scenario makes no sense. It wouldn’t happen.

To use the example the late Antonin Scalia used from an episode of 24 (perhaps the most egregious Fictional Evidence Fallacy ever committed), if there ever is a nuclear bomb planted in Los Angeles, that would literally be one of the worst things that ever happened in the history of the human race—literally a Holocaust in the blink of an eye. We should be prepared to cause extreme suffering and death in order to prevent it. But not only is that event (fortunately) very unlikely, torture would not help us.

Why? Because torture just doesn’t work that well.

It would be too strong to say that it doesn’t work at all; it’s possible that it could produce some valuable intelligence—though clear examples of such results are amazingly hard to come by. There are some social scientists who have found empirical results showing some effectiveness of torture, however. We can’t say with any certainty that it is completely useless. (For obvious reasons, a randomized controlled experiment in torture is wildly unethical, so none have ever been attempted.) But to justify torture it isn’t enough that it could work sometimes; it has to work vastly better than any other method we have.

And our empirical data is in fact reliable enough to show that that is not the case. Torture often produces unreliable information, as we would expect from the game theory involved—your incentive is to stop the pain, not provide accurate intel; the psychological trauma that torture causes actually distorts memory and reasoning; and as a matter of fact basically all the useful intelligence obtained in the War on Terror was obtained through humane interrogation methods. As interrogation experts agree, torture just isn’t that effective.

In principle, there are four basic cases to consider:

1. Torture is vastly more effective than the best humane interrogation methods.

2. Torture is slightly more effective than the best humane interrogation methods.

3. Torture is as effective as the best humane interrogation methods.

4. Torture is less effective than the best humane interrogation methods.

The evidence points most strongly to case 4, which would mean that torture is a no-brainer; if it doesn’t even work as well as other methods, it’s absurd to use it. You’re basically kicking puppies at that point—purely sadistic violence that accomplishes nothing. But the data isn’t clear enough for us to rule out case 3 or even case 2. There is only one case we can strictly rule out, and that is case 1.

But it was only in case 1 that torture could ever be justified!

If you’re trying to justify doing something intrinsically horrible, it’s not enough that it has some slight benefit.

People seem to have this bizarre notion that we have only two choices in morality:

Either we are strict deontologists, and wrong actions can never be justified by good outcomes ever, in which case apparently vaccines are morally wrong, because stabbing children with needles is wrong. Tto be fair, some people seem to actually believe this; but then, some people believe the Earth is less than 10,000 years old.

Or alternatively we are the bizarre strawman concept most people seem to have of utilitarianism, under which any wrong action can be justified by even the slightest good outcome, in which case all you need to do to justify slavery is show that it would lead to a 1% increase in per-capita GDP. Sadly, there honestly do seem to be economists who believe this sort of thing. Here’s one arguing that US chattel slavery was economically efficient, and some of the more extreme arguments for why sweatshops are good can take on this character. Sweatshops may be a necessary evil for the time being, but they are still an evil.

But what utilitarianism actually says (and I consider myself some form of nuanced rule-utilitarian, though actually I sometimes call it “deontological consequentialism” to emphasize that I mean to synthesize the best parts of the two extremes) is not that the ends always justify the means, but that the ends can justify the means—that it can be morally good or even obligatory to do something intrinsically bad (like stabbing children with needles) if it is the best way to accomplish some greater good (like saving them from measles and polio). But the good actually has to be greater, and it has to be the best way to accomplish that good.

To see why this later proviso is important, consider the real-world ethical issues involved in psychology experiments. The benefits of psychology experiments are already quite large, and poised to grow as the science improves; one day the benefits of cognitive science to humanity may be even larger than the benefits of physics and biology are today. Imagine a world without mood disorders or mental illness of any kind; a world without psychopathy, where everyone is compassionate; a world where everyone is achieving their full potential for happiness and self-actualization. Cognitive science may yet make that world possible—and I haven’t even gotten into its applications in artificial intelligence.

To achieve that world, we will need a great many psychology experiments. But does that mean we can just corral people off the street and throw them into psychology experiments without their consent—or perhaps even their knowledge? That we can do whatever we want in those experiments, as long as it’s scientifically useful? No, it does not. We have ethical standards in psychology experiments for a very good reason, and while those ethical standards do slightly reduce the efficiency of the research process, the reduction is small enough that the moral choice is obviously to retain the ethics committees and accept the slight reduction in research efficiency. Yes, randomly throwing people into psychology experiments might actually be slightly better in purely scientific terms (larger and more random samples)—but it would be terrible in moral terms.

Along similar lines, even if torture works about as well or even slightly better than other methods, that’s simply not enough to justify it morally. Making a successful interrogation take 16 days instead of 17 simply wouldn’t be enough benefit to justify the psychological trauma to the suspect (and perhaps the interrogator!), the risk of harm to the falsely accused, or the violation of international human rights law. And in fact a number of terrorism suspects were waterboarded for months, so even the idea that it could shorten the interrogation is pretty implausible. If anything, torture seems to make interrogations take longer and give less reliable information—case 4.

A lot of people seem to have this impression that torture is amazingly, wildly effective, that a suspect who won’t crack after hours of humane interrogation can be tortured for just a few minutes and give you all the information you need. This is exactly what we do not find empirically; if he didn’t crack after hours of talk, he won’t crack after hours of torture. If you literally only have 30 minutes to find the nuke in Los Angeles, I’m sorry; you’re not going to find the nuke in Los Angeles. No adversarial interrogation is ever going to be completed that quickly, no matter what technique you use. Evacuate as many people to safe distances or underground shelters as you can in the time you have left.

This is why the “ticking time-bomb” scenario is so ridiculous (and so insidious); that’s simply not how interrogation works. The best methods we have for “rapid” interrogation of hostile suspects take hours or even days, and they are humane—building trust and rapport is the most important step. The goal is to get the suspect to want to give you accurate information.

For the purposes of the thought experiment, okay, you can stipulate that it would work (this is what the Stanford Encyclopedia of Philosophy does). But now all you’ve done is made the thought experiment more distant from the real-world moral question. The closest real-world examples we’ve ever had involved individual crimes, probably too small to justify the torture (as bad as a murdered child is, think about what you’re doing if you let the police torture people). But by the time the terrorism to be prevented is large enough to really be sufficient justification, it (1) hasn’t happened in the real world and (2) surely involves terrorists who are sufficiently ideologically committed that they’ll be able to resist the torture. If such a situation arises, of course we should try to get information from the suspects—but what we try should be our best methods, the ones that work most consistently, not the ones that “feel right” and maybe happen to work on occasion.

Indeed, the best explanation I have for why people use torture at all, given its horrible effects and mediocre effectiveness at best is that it feels right.

When someone does something terrible (such as an act of terrorism), we rightfully reduce our moral valuation of them relative to everyone else. If you are even tempted to deny this, suppose a terrorist and a random civilian are both inside a burning building and you only have time to save one. Of course you save the civilian and not the terrorist. And that’s still true even if you know that once the terrorist was rescued he’d go to prison and never be a threat to anyone else. He’s just not worth as much.

In the most extreme circumstances, a person can be so terrible that their moral valuation should be effectively zero: If the only person in a burning building is Stalin, I’m not sure you should save him even if you easily could. But it is a grave moral mistake to think that a person’s moral valuation should ever go negative, yet I think this is something that people do when confronted with someone they truly hate. The federal agents torturing those terrorists didn’t merely think of them as worthless—they thought of them as having negative worth. They felt it was a positive good to harm them. But this is fundamentally wrong; no sentient being has negative worth. Some may be so terrible as to have essentially zero worth; and we are often justified in causing harm to some in order to save others. It would have been entirely justified to kill Stalin (as a matter of fact he died of heart disease and old age), to remove the continued threat he posed; but to torture him would not have made the world a better place, and actually might well have made it worse.

Yet I can see how psychologically it could be useful to have a mechanism in our brains that makes us hate someone so much we view them as having negative worth. It makes it a lot easier to harm them when necessary, makes us feel a lot better about ourselves when we do. The idea that any act of homicide is a tragedy but some of them are necessary tragedies is a lot harder to deal with than the idea that some people are just so evil that killing or even torturing them is intrinsically good. But some of the worst things human beings have ever done ultimately came from that place in our brains—and torture is one of them.

Do we always want to internalize externalities?

JDN 2457437

I often talk about the importance of externalitiesa full discussion in this earlier post, and one of their important implications, the tragedy of the commons, in another. Briefly, externalities are consequences of actions incurred upon people who did not perform those actions. Anything I do affecting you that you had no say in, is an externality.

Usually I’m talking about how we want to internalize externalities, meaning that we set up a system of incentives to make it so that the consequences fall upon the people who chose the actions instead of anyone else. If you pollute a river, you should have to pay to clean it up. If you assault someone, you should serve jail time as punishment. If you invent a new technology, you should be rewarded for it. These are all attempts to internalize externalities.

But today I’m going to push back a little, and ask whether we really always want to internalize externalities. If you think carefully, it’s not hard to come up with scenarios where it actually seems fairer to leave the externality in place, or perhaps reduce it somewhat without eliminating it.

For example, suppose indeed that someone invents a great new technology. To be specific, let’s think about Jonas Salk, inventing the polio vaccine. This vaccine saved the lives of thousands of people and saved millions more from pain and suffering. Its value to society is enormous, and of course Salk deserved to be rewarded for it.

But we did not actually fully internalize the externality. If we had, every family whose child was saved from polio would have had to pay Jonas Salk an amount equal to what they saved on medical treatments as a result, or even an amount somehow equal to the value of their child’s life (imagine how offended people would get if you asked that on a survey!). Those millions of people spared from suffering would need to each pay, at minimum, thousands of dollars to Jonas Salk, making him of course a billionaire.

And indeed this is more or less what would have happened, if he had been willing and able to enforce a patent on the vaccine. The inability of some to pay for the vaccine at its monopoly prices would add some deadweight loss, but even that could be removed if Salk Industries had found a way to offer targeted price vouchers that let them precisely price-discriminate so that every single customer paid exactly what they could afford to pay. If that had happened, we would have fully internalized the externality and therefore maximized economic efficiency.

But doesn’t that sound awful? Doesn’t it sound much worse than what we actually did, where Jonas Salk received a great deal of funding and support from governments and universities, and lived out his life comfortably upper-middle class as a tenured university professor?

Now, perhaps he should have been awarded a Nobel Prize—I take that back, there’s no “perhaps” about it, he definitely should have been awarded a Nobel Prize in Medicine, it’s absurd that he did not—which means that I at least do feel the externality should have been internalized a bit more than it was. But a Nobel Prize is only 10 million SEK, about $1.1 million. That’s about enough to be independently wealthy and live comfortably for the rest of your life; but it’s a small fraction of the roughly $7 billion he could have gotten if he had patented the vaccine. Yet while the possible world in which he wins a Nobel is better than this one, I’m fairly well convinced that the possible world in which he patents the vaccine and becomes a billionaire is considerably worse.

Internalizing externalities makes sense if your goal is to maximize total surplus (a concept I explain further in the linked post), but total surplus is actually a terrible measure of human welfare.

Total surplus counts every dollar of willingness-to-pay exactly the same across different people, regardless of whether they live on $400 per year or $4 billion.

It also takes no account whatsoever of how wealth is distributed. Suppose a new technology adds $10 billion in wealth to the world. As far as total surplus, it makes no difference whether that $10 billion is spread evenly across the entire planet, distributed among a city of a million people, concentrated in a small town of 2,000, or even held entirely in the bank account of a single man.

Particularly a propos of the Salk example, total surplus makes no distinction between these two scenarios: a perfectly-competitive market where everything is sold at a fair price, and a perfectly price-discriminating monopoly, where everything is sold at the very highest possible price each person would be willing to pay.

This is a perfectly-competitive market, where the benefits are more or less equally (in this case exactly equally, but that need not be true in real life) between sellers and buyers:

elastic_supply_competitive_labeled

This is a perfectly price-discriminating monopoly, where the benefits accrue entirely to the corporation selling the good:

elastic_supply_price_discrimination

In the former case, the company profits, consumers are better off, everyone is happy. In the latter case, the company reaps all the benefits and everyone else is left exactly as they were. In real terms those are obviously very different outcomes—the former being what we want, the latter being the cyberpunk dystopia we seem to be hurtling mercilessly toward. But in terms of total surplus, and therefore the kind of “efficiency” that is maximize by internalizing all externalities, they are indistinguishable.

In fact (as I hope to publish a paper about at some point), the way willingness-to-pay works, it weights rich people more. Redistributing goods from the poor to the rich will typically increase total surplus.

Here’s an example. Suppose there is a cake, which is sufficiently delicious that it offers 2 milliQALY in utility to whoever consumes it (this is a truly fabulous cake). Suppose there are two people to whom we might give this cake: Richie, who has $10 million in annual income, and Hungry, who has only $1,000 in annual income. How much will each of them be willing to pay?

Well, assuming logarithmic marginal utility of wealth (which is itself probably biasing slightly in favor of the rich), 1 milliQALY is about $1 to Hungry, so Hungry will be willing to pay $2 for the cake. To Richie, however, 1 milliQALY is about $10,000; so he will be willing to pay a whopping $20,000 for this cake.

What this means is that the cake will almost certainly be sold to Richie; and if we proposed a policy to redistribute the cake from Richie to Hungry, economists would emerge to tell us that we have just reduced total surplus by $19,998 and thereby committed a great sin against economic efficiency. They will cajole us into returning the cake to Richie and thus raising total surplus by $19,998 once more.

This despite the fact that I stipulated that the cake is worth just as much in real terms to Hungry as it is to Richie; the difference is due to their wildly differing marginal utility of wealth.

Indeed, it gets worse, because even if we suppose that the cake is worth much more in real utility to Hungry—because he is in fact hungry—it can still easily turn out that Richie’s willingness-to-pay is substantially higher. Suppose that Hungry actually gets 20 milliQALY out of eating the cake, while Richie still only gets 2 milliQALY. Hungry’s willingness-to-pay is now $20, but Richie is still going to end up with the cake.

Now, if your thought is, “Why would Richie pay $20,000, when he can go to another store and get another cake that’s just as good for $20?” Well, he wouldn’t—but in the sense we mean for total surplus, willingness-to-pay isn’t just what you’d actually be willing to pay given the actual prices of the goods, but the absolute maximum price you’d be willing to pay to get that good under any circumstances. It is instead the marginal utility of the good divided by your marginal utility of wealth. In this sense the cake is “worth” $20,000 to Richie, and “worth” substantially less to Hungry—but not because it’s actually worth less in real terms, but simply because Richie has so much more money.

Even economists often equate these two, implicitly assuming that we are spending our money up to the point where our marginal willingness-to-pay is the actual price we choose to pay; but in general our willingness-to-pay is higher than the price if we are willing to buy the good at all. The consumer surplus we get from goods is in fact equal to the difference between willingness-to-pay and actual price paid, summed up over all the goods we have purchased.

Internalizing all externalities would definitely maximize total surplus—but would it actually maximize happiness? Probably not.

If you asked most people what their marginal utility of wealth is, they’d have no idea what you’re talking about. But most people do actually have an intuitive sense that a dollar is worth more to a homeless person than it is to a millionaire, and that’s really all we mean by diminishing marginal utility of wealth.

I think the reason we’re uncomfortable with the idea of Jonas Salk getting $7 billion from selling the polio vaccine, rather than the same number of people getting the polio vaccine and Jonas Salk only getting the $1.1 million from a Nobel Prize, is that we intuitively grasp that after that $1.1 million makes him independently wealthy, the rest of the money is just going to sit in some stock account and continue making even more money, while if we’d let the families keep it they would have put it to much better use raising their children who are now protected from polio. We do want to reward Salk for his great accomplishment, but we don’t see why we should keep throwing cash at him when it could obviously be spent in better ways.

And indeed I think this intuition is correct; great accomplishments—which is to say, large positive externalities—should be rewarded, but not in direct proportion. Maybe there should be some threshold above which we say, “You know what? You’re rich enough now; we can stop giving you money.” Or maybe it should simply damp down very quickly, so that a contribution which is worth $10 billion to the world pays only slightly more than one that is worth $100 million, but a contribution that is worth $100,000 pays considerably more than one which is only worth $10,000.

What it ultimately comes down to is that if we make all the benefits incur to the person who did it, there aren’t any benefits anymore. The whole point of Jonas Salk inventing the polio vaccine (or Einstein discovering relativity, or Darwin figuring out natural selection, or any great achievement) is that it will benefit the rest of humanity, preferably on to future generations. If you managed to fully internalize that externality, this would no longer be true; Salk and Einstein and Darwin would have become fabulously wealthy, and then somehow we’d all have to continue paying into their estates or something an amount equal to the benefits we received from their discoveries. (Every time you use your GPS, pay a royalty to the Einsteins. Every time you take a pill, pay a royalty to the Darwins.) At some point we’d probably get fed up and decide we’re no better off with them than without them—which is exactly by construction how we should feel if the externality were fully internalized.

Internalizing negative externalities is much less problematic—it’s your mess, clean it up. We don’t want other people to be harmed by your actions, and if we can pull that off that’s fantastic. (In reality, we usually can’t fully internalize negative externalities, but we can at least try.)

But maybe internalizing positive externalities really isn’t so great after all.

What do we mean by “risk”?

JDN 2457118 EDT 20:50.

In an earlier post I talked about how, empirically, expected utility theory can’t explain the fact that we buy both insurance and lottery tickets, and how, normatively it really doesn’t make a lot of sense to buy lottery tickets precisely because of what expected utility theory says about them.

But today I’d like to talk about one of the major problems with expected utility theory, which I consider one of the major unexplored frontiers of economics: Expected utility theory treats all kinds of risk exactly the same.

In reality there are three kinds of risk: The first is what I’ll call classical risk, which is like the game of roulette; the odds are well-defined and known in advance, and you can play the game a large number of times and average out the results. This is where expected utility theory really shines; if you are dealing with classical risk, expected utility is obviously the way to go and Von Neumann and Morgenstern quite literally proved mathematically that anything else is irrational.

The second is uncertainty, a distinction which was most famously expounded by Frank Knight, an economist at the University of Chicago. (Chicago is a funny place; on the one hand they are a haven for the madness that is Austrian economics; on the other hand they have led the charge in behavioral and cognitive economics. Knight was a perfect fit, because he was a little of both.) Uncertainty is risk under ill-defined or unknown probabilities, where there is no way to play the game twice. Most real-world “risk” is actually uncertainty: Will the People’s Republic of China collapse in the 21st century? How many deaths will global warming cause? Will human beings ever colonize Mars? Is P = NP? None of those questions have known answers, but nor can we clearly assign probabilities either; Either P = NP or not, as a mathematical theorem (or, like the continuum hypothesis, it’s independent of ZFC, the most bizarre possibility of all), and it’s not as if someone is rolling dice to decide how many people global warming will kill. You can think of this in terms of “possible worlds”, though actually most modal theorists would tell you that we can’t even say that P=NP is possible (nor can we say it isn’t possible!) because, as a necessary statement, it can only be possible if it is actually true; this follows from the S5 axiom of modal logic, and you know what, even I am already bored with that sentence. Clearly there is some sense in which P=NP is possible, and if that’s not what modal logic says then so much the worse for modal logic. I am not a modal realist (not to be confused with a moral realist, which I am); I don’t think that possible worlds are real things out there somewhere. I think possibility is ultimately a statement about ignorance, and since we don’t know that P=NP is false then I contend that it is possible that it is true. Put another way, it would not be obviously irrational to place a bet that P=NP will be proved true by 2100; but if we can’t even say that it is possible, how can that be?

Anyway, that’s the mess that uncertainty puts us in, and almost everything is made of uncertainty. Expected utility theory basically falls apart under uncertainty; it doesn’t even know how to give an answer, let alone one that is correct. In reality what we usually end up doing is waving our hands and trying to assign a probability anyway—because we simply don’t know what else to do.

The third one is not one that’s usually talked about, yet I think it’s quite important; I will call it one-shot risk. The probabilities are known or at least reasonably well approximated, but you only get to play the game once. You can also generalize to few-shot risk, where you can play a small number of times, where “small” is defined relative to the probabilities involved; this is a little vaguer, but basically what I have in mind is that even though you can play more than once, you can’t play enough times to realistically expect the rarest outcomes to occur. Expected utility theory almost works on one-shot and few-shot risk, but you have to be very careful about taking it literally.

I think an example make things clearer: Playing the lottery is a few-shot risk. You can play the lottery multiple times, yes; potentially hundreds of times in fact. But hundreds of times is nothing compared to the 1 in 400 million chance you have of actually winning. You know that probability; it can be computed exactly from the rules of the game. But nonetheless expected utility theory runs into some serious problems here.

If we were playing a classical risk game, expected utility would obviously be right. So for example if you know that you will live one billion years, and you are offered the chance to play a game (somehow compensating for the mind-boggling levels of inflation, economic growth, transhuman transcendence, and/or total extinction that will occur during that vast expanse of time) in which at each year you can either have a guaranteed $40,000 of inflation-adjusted income or a 99.999,999,75% chance of $39,999 of inflation-adjusted income and a 0.000,000,25% chance of $100 million in inflation-adjusted income—which will disappear at the end of the year, along with everything you bought with it, so that each year you start afresh. Should you take the second option? Absolutely not, and expected utility theory explains why; that one or two years where you’ll experience 8 QALY per year isn’t worth dropping from 4.602056 QALY per year to 4.602049 QALY per year for the other nine hundred and ninety-eight million years. (Can you even fathom how long that is? From here, one billion years is all the way back to the Mesoproterozoic Era, which we think is when single-celled organisms first began to reproduce sexually. The gain is to be Mitt Romney for a year or two; the loss is the value of a dollar each year over and over again for the entire time that has elapsed since the existence of gamete meiosis.) I think it goes without saying that this whole situation is almost unimaginably bizarre. Yet that is implicitly what we’re assuming when we use expected utility theory to assess whether you should buy lottery tickets.

The real situation is more like this: There’s one world you can end up in, and almost certainly will, in which you buy lottery tickets every year and end up with an income of $39,999 instead of $40,000. There is another world, so unlikely as to be barely worth considering, yet not totally impossible, in which you get $100 million and you are completely set for life and able to live however you want for the rest of your life. Averaging over those two worlds is a really weird thing to do; what do we even mean by doing that? You don’t experience one world 0.000,000,25% as much as the other (whereas in the billion-year scenario, that is exactly what you do); you only experience one world or the other.

In fact, it’s worse than this, because if a classical risk game is such that you can play it as many times as you want as quickly as you want, we don’t even need expected utility theory—expected money theory will do. If you can play a game where you have a 50% chance of winning $200,000 and a 50% chance of losing $50,000, which you can play up to once an hour for the next 48 hours, and you will be extended any credit necessary to cover any losses, you’d be insane not to play; your 99.9% confidence level of wealth at the end of the two days is from $850,000 to $6,180,000. While you may lose money for awhile, it is vanishingly unlikely that you will end up losing more than you gain.

Yet if you are offered the chance to play this game only once, you probably should not take it, and the reason why then comes back to expected utility. If you have good access to credit you might consider it, because going $50,000 into debt is bad but not unbearably so (I did, going to college) and gaining $200,000 might actually be enough better to justify the risk. Then the effect can be averaged over your lifetime; let’s say you make $50,000 per year over 40 years. Losing $50,000 means making your average income $48,750, while gaining $200,000 means making your average income $55,000; so your QALY per year go from a guaranteed 4.70 to a 50% chance of 4.69 and a 50% chance of 4.74; that raises your expected utility from 4.70 to 4.715.

But if you don’t have good access to credit and your income for this year is $50,000, then losing $50,000 means losing everything you have and living in poverty or even starving to death. The benefits of raising your income by $200,000 this year aren’t nearly great enough to take that chance. Your expected utility goes from 4.70 to a 50% chance of 5.30 and a 50% chance of zero.

So expected utility theory only seems to properly apply if we can play the game enough times that the improbable events are likely to happen a few times, but not so many times that we can be sure our money will approach the average. And that’s assuming we know the odds and we aren’t just stuck with uncertainty.

Unfortunately, I don’t have a good alternative; so far expected utility theory may actually be the best we have. But it remains deeply unsatisfying, and I like to think we’ll one day come up with something better.

Scope neglect and the question of optimal altruism

JDN 2457090 EDT 16:15.

We’re now on Eastern Daylight Time because of this bizarre tradition of shifting our time zone forward for half of the year. It’s supposed to save energy, but a natural experiment in India suggests it actually increases energy demand. So why do we do it? Like every ridiculous tradition (have you ever tried to explain Groundhog Day to someone from another country?), we do it because we’ve always done it.
This week’s topic is scope neglect, one of the most pervasive—and pernicious—cognitive heuristics human beings face. Scope neglect raises a great many challenges not only practically but also theoretically—it raises what I call the question of optimal altruism.

The question is simple to ask yet remarkably challenging to answer: How much should we be willing to sacrifice in order to benefit others? If we think of this as a number, your solidarity coefficient (s), it is equal to the cost you are willing to pay divided by the benefit your action has for someone else: s B > C.

This is analogous to the biological concept relatedness (r), on which Hamilton’s Rule applies: r B > C. Solidarity is the psychological analogue; instead of valuing people based on their genetic similarity to you, you value them based on… well, that’s the problem.

I can easily place upper and lower bounds: The lower bound is zero: You should definitely be willing to sacrifice something to help other people—otherwise you are a psychopath. The upper bound is one: There’s no point in paying more cost than you produce in benefit, and in fact even paying the same cost to yourself as you yield in benefits for other people doesn’t make a lot of sense, because it means that your own self-interest is meaningless and the fact that you understand your own needs better than the needs of others is also irrelevant.

But beyond that, it gets a lot harder—and that may explain why we suffer scope neglect in the first place. Should it be 90%? 50%? 10%? 1%? How should it vary between friends versus family versus strangers? It’s really hard to say. And this inability to precisely decide how much other people should be worth to us may be part of why we suffer scope neglect.

Scope neglect is the fact that we are not willing to expend effort or money in direct proportion to the benefit it would have. When different groups were asked how much they would be willing to donate in order to save the lives of 2,000 birds, 20,000 birds, or 200,000 birds, the answers they gave were statistically indistinguishable—always about $80. But however much a bird’s life is worth to you, shouldn’t 200,000 birds be worth, well, 200,000 times as much? In fact, more than that, because the marginal utility of wealth is decreasing, but I see no reason to think that the marginal utility of birds decreases nearly as fast.

But therein lies the problem: Usually we can’t pay 200,000 times as much. I’d feel like a horrible person if I weren’t willing to expend at least $10 or an equivalent amount of effort in order to save a bird. To save 200,000 birds that means I’d owe $2 million—and I simply don’t have $2 million.

You can get similar results to the bird experiment if you use children—though, as one might hope, the absolute numbers are a bit bigger, usually more like $500 to $1000. (And this, it turns out, is actually about how much it actually costs to save a child’s life by a particularly efficient means, such as anti-malaria nets, de-worming, or direct cash transfer. So please, by all means, give $1000 to UNICEF or the Against Malaria Foundation. If you can’t give $1000, give $100; if you can’t give $100, give $10.) It doesn’t much matter whether you say that the project will save 500 children, 5,000 children, or 50,000 children—people still will give about $500 to $1000. But once again, if I’m willing to spend $1000 to save a child—and I definitely am—how much should I be willing to spend to end malaria, which kills 500,000 children a year? Apparently $500 million, which not only do I not have, I almost certainly will not make that much money cumulatively through my entire life. ($2 million, on the other hand, I almost certainly will make cumulatively—the median income of an economist is $90,000 per year, so if I work for at least 22 years with that as my average income I’ll have cumulatively made $2 million. My net wealth may never be that high—though if I get better positions, or I’m lucky enough or clever enough with the stock market it might—but my cumulative income almost certainly will. Indeed, the average gain in cumulative income from a college degree is about $1 million. Because it takes time—time is money—and loans carry interest, this gives it a net present value of about $300,000.)

But maybe scope neglect isn’t such a bad thing after all. There is a very serious problem with these sort of moral dilemmas: The question didn’t say I would single-handedly save 200,000 birds—and indeed, that notion seems quite ridiculous. If I knew that I could actually save 200,000 birds and I were the only one who could do it, dammit, I would try to come up with that $2 million. I might not succeed, but I really would try as hard as I could.

And if I could single-handedly end malaria, I hereby vow that I would do anything it took to achieve that. Short of mass murder, anything I could do couldn’t be a higher cost to the world than malaria itself. I have no idea how I’d come up with $500 million, but I’d certainly try. Bill Gates could easily come up with that $500 million—so he did. In fact he endowed the Gates Foundation with $28 billion, and they’ve spent $1.3 billion of that on fighting malaria, saving hundreds of thousands of lives.

With this in mind, what is scope neglect really about? I think it’s about coordination. It’s not that people don’t care more about 200,000 birds than they do about 2,000; and it’s certainly not that they don’t care more about 50,000 children than they do about 500. Rather, the problem is that people don’t know how many other people are likely to donate, or how expensive the total project is likely to be; and we don’t know how much we should be willing to pay to save the life of a bird or a child.

Hence, what we basically do is give up; since we can’t actually assess the marginal utility of our donation dollars, we fall back on our automatic emotional response. Our mind focuses itself on visualizing that single bird covered in oil, or that single child suffering from malaria. We then hope that the representative heuristic will guide us in how much to give. Or we follow social norms, and give as much as we think others would expect us to give.

While many in the effective altruism community take this to be a failing, they never actually say what we should do—they never give us a figure for how much money we should be willing to donate to save the life of a child. Instead they retreat to abstraction, saying that whatever it is we’re willing to give to save a child, we should be willing to give 50,000 times as much to save 50,000 children.

But it’s not that simple. A bigger project may attract more supporters; if the two occur in direct proportion, then constant donation is the optimal response. Since it’s probably not actually proportional, you likely should give somewhat more to causes that affect more people; but exactly how much more is an astonishingly difficult question. I really don’t blame people—or myself—for only giving a little bit more to causes with larger impact, because actually getting the right answer is so incredibly hard. This is why it’s so important that we have institutions like GiveWell and Charity Navigator which do the hard work to research the effectiveness of charities and tell us which ones we should give to.

Yet even if we can properly prioritize which charities to give to first, that still leaves the question of how much each of us should give. 1% of our income? 5%? 10%? 20%? 50%? Should we give so much that we throw ourselves into the same poverty we are trying to save others from?

In his earlier work Peter Singer seemed to think we should give so much that it throws us into poverty ourselves; he asked us to literally compare every single purchase and ask ourselves whether a year of lattes or a nicer car is worth a child’s life. Of course even he doesn’t live that way, and in his later books Singer seems to have realized this, and now recommends the far more modest standard that everyone give at least 1% of their income. (He himself gives about 33%, but he’s also very rich so he doesn’t feel it nearly as much.) I think he may have overcompensated; while if literally everyone gave at least 1% that would be more than enough to end world hunger and solve many other problems—world nominal GDP is over $70 trillion, so 1% of that is $700 billion a year—we know that this won’t happen. Some will give more, others less; most will give nothing at all. Hence I think those of us who give should give more than our share; hence I lean toward figures more like 5% or 10%.

But then, why not 50% or 90%? It is very difficult for me to argue on principle why we shouldn’t be expected to give that much. Because my income is such a small proportion of the total donations, the marginal utility of each dollar I give is basically constant—and quite high; if it takes about $1000 to save a child’s life on average, and each of these children will then live about 60 more years at about half the world average happiness, that’s about 30 QALY per $1000, or about 30 milliQALY per dollar. Even at my current level of income (incidentally about as much as I think the US basic income should be), I’m benefiting myself only about 150 microQALY per dollar—so my money is worth about 200 times as much to those children as it is to me.

So now we have to ask ourselves the really uncomfortable question: How much do I value those children, relative to myself? If I am at all honest, the value is not 1; I’m not prepared to die for someone I’ve never met 10,000 kilometers away in a nation I’ve never even visited, nor am I prepared to give away all my possessions and throw myself into the same starvation I am hoping to save them from. I value my closest friends and family approximately the same as myself, but I have to admit that I value random strangers considerably less.

Do I really value them at less than 1%, as these figures would seem to imply? I feel like a monster saying that, but maybe it really isn’t so terrible—after all, most economists seem to think that the optimal solidarity coefficient is in fact zero. Maybe we need to become more comfortable admitting that random strangers aren’t worth that much to us, simply so that we can coherently acknowledge that they aren’t worth nothing. Very few of us actually give away all our possessions, after all.

Then again, what do we mean by worth? I can say from direct experience that a single migraine causes me vastly more pain than learning about the death of 200,000 people in an earthquake in Southeast Asia. And while I gave about $100 to the relief efforts involved in that earthquake, I’ve spent considerably more on migraine treatments—thousands, once you include health insurance. But given the chance, would I be willing to suffer a migraine to prevent such an earthquake? Without hesitation. So the amount of pain we feel is not the same as the amount of money we pay, which is not the same as what we would be willing to sacrifice. I think the latter is more indicative of how much people’s lives are really worth to us—but then, what we pay is what has the most direct effect on the world.

It’s actually possible to justify not dying or selling all my possessions even if my solidarity coefficient is much higher—it just leads to some really questionable conclusions. Essentially the argument is this: I am an asset. I have what economists call “human capital”—my health, my intelligence, my education—that gives me the opportunity to affect the world in ways those children cannot. In my ideal imagined future (albeit improbable) in which I actually become President of the World Bank and have the authority to set global development policy, I myself could actually have a marginal impact of megaQALY—millions of person-years of better life. In the far more likely scenario in which I attain some mid-level research or advisory position, I could be one of thousands of people who together have that sort of impact—which still means my own marginal effect is on the order of kiloQALY. And clearly it’s true that if I died, or even if I sold all my possessions, these events would no longer be possible.

The problem with that reasoning is that it’s wildly implausible to say that everyone in the First World are in this same sort of position—Peter Singer can say that, and maybe I can say that, and indeed hundreds of development economists can say that—but at least 99.9% of the First World population are not development economists, nor are they physicists likely to invent cold fusion, nor biomedical engineers likely to cure HIV, nor aid workers who distribute anti-malaria nets and polio vaccines, nor politicians who set national policy, nor diplomats who influence international relations, nor authors whose bestselling books raise worldwide consciousness. Yet I am not comfortable saying that all the world’s teachers, secretaries, airline pilots and truck drivers should give away their possessions either. (Maybe all the world’s bankers and CEOs should—or at least most of them.)

Is it enough that our economy would collapse without teachers, secretaries, airline pilots and truck drivers? But this seems rather like the fact that if everyone in the world visited the same restaurant there wouldn’t be enough room. Surely we could do without any individual teacher, any individual truck driver? If everyone gave the same proportion of their income, 1% would be more than enough to end malaria and world hunger. But we know that everyone won’t give, and the job won’t get done if those of us who do give only 1%.

Moreover, it’s also clearly not the case that everything I spend money on makes me more likely to become a successful and influential development economist. Buying a suit and a car actually clearly does—it’s much easier to get good jobs that way. Even leisure can be justified to some extent, since human beings need leisure and there’s no sense burning myself out before I get anything done. But do I need both of my video game systems? Couldn’t I buy a bit less Coke Zero? What if I watched a 20-inch TV instead of a 40-inch one? I still have free time; could I get another job and donate that money? This is the sort of question Peter Singer tells us to ask ourselves, and it quickly leads to a painfully spartan existence in which most of our time is spent thinking about whether what we’re doing is advancing or damaging the cause of ending world hunger. But then the cost of that stress and cognitive effort must be included; but how do you optimize your own cognitive effort? You need to think about the cost of thinking about the cost of thinking… and on and on. This is why bounded rationality modeling is hard, even though it’s plainly essential to both cognitive science and computer science. (John Stuart Mill wrote an essay that resonates deeply with me about how the pressure to change the world drove him into depression, and how he learned to accept that he could still change the world even if he weren’t constantly pressuring himself to do so—and indeed he did. James Mill set out to create in his son, John Stuart Mill, the greatest philosopher in the history of the world—and I believe that he succeeded.)

Perhaps we should figure out what proportion of the world’s people are likely to give, and how much we need altogether, and then assign the amount we expect from each of them based on that? The more money you ask from each, the fewer people are likely to give. This creates an optimization problem akin to setting the price of a product under monopoly—monopolies maximize profits by carefully balancing the quantity sold with the price at which they sell, and perhaps a similar balance would allow us to maximize development aid. But wouldn’t it be better if we could simply increase the number of people who give, so that we don’t have to ask so much of those who are generous? That means tax-funded foreign aid is the way to go, because it ensures coordination. And indeed I do favor increasing foreign aid to about 1% of GDP—in the US it is currently about $50 billion, 0.3% of GDP, a little more than 1% of the Federal budget. (Most people who say we should “cut” foreign aid don’t realize how small it already is.) But foreign aid is coercive; wouldn’t it be better if people would give voluntarily?

I don’t have a simple answer. I don’t know how much other people’s lives ought to be worth to us, or what it means for our decisions once we assign that value. But I hope I’ve convinced you that this problem is an important one—and made you think a little more about scope neglect and why we have it.

Prospect Theory: Why we buy insurance and lottery tickets

JDN 2457061 PST 14:18.

Today’s topic is called prospect theory. Prospect theory is basically what put cognitive economics on the map; it was the knock-down argument that Kahneman used to show that human beings are not completely rational in their economic decisions. It all goes back to a 1979 paper by Kahneman and Tversky that now has 34000 citations (yes, we’ve been having this argument for a rather long time now). In the 1990s it was refined into cumulative prospect theory, which is more mathematically precise but basically the same idea.

What was that argument? People buy both insurance and lottery tickets.

The “both” is very important. Buying insurance can definitely be rational—indeed, typically is. Buying lottery tickets could theoretically be rational, under very particular circumstances. But they cannot both be rational at the same time.

To see why, let’s talk some more about marginal utility of wealth. Recall that a dollar is not worth the same to everyone; to a billionaire a dollar is a rounding error, to most of us it is a bottle of Coke, but to a starving child in Ghana it could be life itself. We typically observe diminishing marginal utility of wealth—the more money you have, the less another dollar is worth to you.

If we sketch a graph of your utility versus wealth it would look something like this:

Marginal_utility_wealth

Notice how it increases as your wealth increases, but at a rapidly diminishing rate.

If you have diminishing marginal utility of wealth, you are what we call risk-averse. If you are risk-averse, you’ll (sometimes) want to buy insurance. Let’s suppose the units on that graph are tens of thousands of dollars. Suppose you currently have an income of $50,000. You are offered the chance to pay $10,000 a year to buy unemployment insurance, so that if you lose your job, instead of making $10,000 on welfare you’ll make $30,000 on unemployment. You think you have about a 20% chance of losing your job.

If you had constant marginal utility of wealth, this would not be a good deal for you. Your expected value of money would be reduced if you buy the insurance: Before you had an 80% chance of $50,000 and a 20% chance of $10,000 so your expected amount of money is $42,000. With the insurance you have an 80% chance of $40,000 and a 20% chance of $30,000 so your expected amount of money is $38,000. Why would you take such a deal? That’s like giving up $4,000 isn’t it?

Well, let’s look back at that utility graph. At $50,000 your utility is 1.80, uh… units, er… let’s say QALY. 1.80 QALY per year, meaning you live 80% better than the average human. Maybe, I guess? Doesn’t seem too far off. In any case, the units of measurement aren’t that important.

Insurance_options

By buying insurance your effective income goes down to $40,000 per year, which lowers your utility to 1.70 QALY. That’s a fairly significant hit, but it’s not unbearable. If you lose your job (20% chance), you’ll fall down to $30,000 and have a utility of 1.55 QALY. Again, noticeable, but bearable. Your overall expected utility with insurance is therefore 1.67 QALY.

But what if you don’t buy insurance? Well then you have a 20% chance of taking a big hit and falling all the way down to $10,000 where your utility is only 1.00 QALY. Your expected utility is therefore only 1.64 QALY. You’re better off going with the insurance.

And this is how insurance companies make a profit (well; the legitimate way anyway; they also like to gouge people and deny cancer patients of course); on average, they make more from each customer than they pay out, but customers are still better off because they are protected against big losses. In this case, the insurance company profits $4,000 per customer per year, customers each get 30 milliQALY per year (about the same utility as an extra $2,000 more or less), everyone is happy.

But if this is your marginal utility of wealth—and it most likely is, approximately—then you would never want to buy a lottery ticket. Let’s suppose you actually have pretty good odds; it’s a 1 in 1 million chance of $1 million for a ticket that costs $2. This means that the state is going to take in about $2 million for every $1 million they pay out to a winner.

That’s about as good as your odds for a lottery are ever going to get; usually it’s more like a 1 in 400 million chance of $150 million for $1, which is an even bigger difference than it sounds, because $150 million is nowhere near 150 times as good as $1 million. It’s a bit better from the state’s perspective though, because they get to receive $400 million for every $150 million they pay out.

For your convenience I have zoomed out the graph so that you can see 100, which is an income of $1 million (which you’ll have this year if you win; to get it next year, you’ll have to play again). You’ll notice I did not have to zoom out the vertical axis, because 20 times as much money only ends up being about 2 times as much utility. I’ve marked with lines the utility of $50,000 (1.80, as we said before) versus $1 million (3.30).

Lottery_utility

What about the utility of $49,998 which is what you’ll have if you buy the ticket and lose? At this number of decimal places you can’t see the difference, so I’ll need to go out a few more. At $50,000 you have 1.80472 QALY. At $49,998 you have 1.80470 QALY. That $2 only costs you 0.00002 QALY, 20 microQALY. Not much, really; but of course not, it’s only $2.

How much does the 1 in 1 million chance of $1 million give you? Even less than that. Remember, the utility gain for going from $50,000 to $1 million is only 1.50 QALY. So you’re adding one one-millionth of that in expected utility, which is of course 1.5 microQALY, or 0.0000015 QALY.

That $2 may not seem like it’s worth much, but that 1 in 1 million chance of $1 million is worth less than one tenth as much. Again, I’ve tried to make these figures fairly realistic; they are by no means exact (I don’t actually think $49,998 corresponds to exactly 1.804699 QALY), but the order of magnitude difference is right. You gain about ten times as much utility from spending that $2 on something you want than you do on taking the chance at $1 million.

I said before that it is theoretically possible for you to have a utility function for which the lottery would be rational. For that you’d need to have increasing marginal utility of wealth, so that you could be what we call risk-seeking. Your utility function would have to look like this:

Weird_utility

There’s no way marginal utility of wealth looks like that. This would be saying that it would hurt Bill Gates more to lose $1 than it would hurt a starving child in Ghana, which makes no sense at all. (It certainly would makes you wonder why he’s so willing to give it to them.) So frankly even if we didn’t buy insurance the fact that we buy lottery tickets would already look pretty irrational.

But in order for it to be rational to buy both lottery tickets and insurance, our utility function would have to be totally nonsensical. Maybe it could look like this or something; marginal utility decreases normally for awhile, and then suddenly starts going upward again for no apparent reason:

Weirder_utility

Clearly it does not actually look like that. Not only would this mean that Bill Gates is hurt more by losing $1 than the child in Ghana, we have this bizarre situation where the middle class are the people who have the lowest marginal utility of wealth in the world. Both the rich and the poor would need to have higher marginal utility of wealth than we do. This would mean that apparently yachts are just amazing and we have no idea. Riding a yacht is the pinnacle of human experience, a transcendence beyond our wildest imaginings; and riding a slightly bigger yacht is even more amazing and transcendent. Love and the joy of a life well-lived pale in comparison to the ecstasy of adding just one more layer of gold plate to your Ferrari collection.

Where increasing marginal utility is ridiculous, this is outright special pleading. You’re just making up bizarre utility functions that perfectly line up with whatever behavior people happen to have so that you can still call it rational. It’s like saying, “It could be perfectly rational! Maybe he enjoys banging his head against the wall!”

Kahneman and Tversky had a better idea. They realized that human beings aren’t so great at assessing probability, and furthermore tend not to think in terms of total amounts of wealth or annual income at all, but in terms of losses and gains. Through a series of clever experiments they showed that we are not so much risk-averse as we are loss-averse; we are actually willing to take more risk if it means that we will be able to avoid a loss.

In effect, we seem to be acting as if our utility function looks like this, where the zero no longer means “zero income”, it means “whatever we have right now“:

Prospect_theory

We tend to weight losses about twice as much as gains, and we tend to assume that losses also diminish in their marginal effect the same way that gains do. That is, we would only take a 50% chance to lose $1000 if it meant a 50% chance to gain $2000; but we’d take a 10% chance at losing $10,000 to save ourselves from a guaranteed loss of $1000.

This can explain why we buy insurance, provided that you frame it correctly. One of the things about prospect theory—and about human behavior in general—is that it exhibits framing effects: The answer we give depends upon the way you ask the question. That’s so totally obviously irrational it’s honestly hard to believe that we do it; but we do, and sometimes in really important situations. Doctors—doctors—will decide a moral dilemma differently based on whether you describe it as “saving 400 out of 600 patients” or “letting 200 out of 600 patients die”.

In this case, you need to frame insurance as the default option, and not buying insurance as an extra risk you are taking. Then saving money by not buying insurance is a gain, and therefore less important, while a higher risk of a bad outcome is a loss, and therefore important.

If you frame it the other way, with not buying insurance as the default option, then buying insurance is taking a loss by making insurance payments, only to get a gain if the insurance pays out. Suddenly the exact same insurance policy looks less attractive. This is a big part of why Obamacare has been effective but unpopular. It was set up as a fine—a loss—if you don’t buy insurance, rather than as a bonus—a gain—if you do buy insurance. The latter would be more expensive, but we could just make it up by taxing something else; and it might have made Obamacare more popular, because people would see the government as giving them something instead of taking something away. But the fine does a better job of framing insurance as the default option, so it motivates more people to actually buy insurance.

But even that would still not be enough to explain how it is rational to buy lottery tickets (Have I mentioned how it’s really not a good idea to buy lottery tickets?), because buying a ticket is a loss and winning the lottery is a gain. You actually have to get people to somehow frame not winning the lottery as a loss, making winning the default option despite the fact that it is absurdly unlikely. But I have definitely heard people say things like this: “Well if my numbers come up and I didn’t play that week, how would I feel then?” Pretty bad, I’ll grant you. But how much you wanna bet that never happens? (They’ll bet… the price of the ticket, apparently.)

In order for that to work, people either need to dramatically overestimate the probability of winning, or else ignore it entirely. Both of those things totally happen.

First, we overestimate the probability of rare events and underestimate the probability of common events—this is actually the part that makes it cumulative prospect theory instead of just regular prospect theory. If you make a graph of perceived probability versus actual probability, it looks like this:

cumulative_prospect

We don’t make much distinction between 40% and 60%, even though that’s actually pretty big; but we make a huge distinction between 0% and 0.00001% even though that’s actually really tiny. I think we basically have categories in our heads: “Never, almost never, rarely, sometimes, often, usually, almost always, always.” Moving from 0% to 0.00001% is going from “never” to “almost never”, but going from 40% to 60% is still in “often”. (And that for some reason reminded me of “Well, hardly ever!”)

But that’s not even the worst of it. After all that work to explain how we can make sense of people’s behavior in terms of something like a utility function (albeit a distorted one), I think there’s often a simpler explanation still: Regret aversion under total neglect of probability.

Neglect of probability is self-explanatory: You totally ignore the probability. But what’s regret aversion, exactly? Unfortunately I’ve had trouble finding any good popular sources on the topic; it’s all scholarly stuff. (Maybe I’m more cutting-edge than I thought!)

The basic idea that is that you minimize regret, where regret can be formalized as the difference in utility between the outcome you got and the best outcome you could have gotten. In effect, it doesn’t matter whether something is likely or unlikely; you only care how bad it is.

This explains insurance and lottery tickets in one fell swoop: With insurance, you have the choice of risking a big loss (big regret) which you can avoid by paying a small amount (small regret). You take the small regret, and buy insurance. With lottery tickets, you have the chance of getting a large gain (big regret if you don’t) which you gain by paying a small amount (small regret).

This can also explain why a typical American’s fears go in the order terrorists > Ebola > sharks > > cars > cheeseburgers, while the actual risk of dying goes in almost the opposite order, cheeseburgers > cars > > terrorists > sharks > Ebola. (Terrorists are scarier than sharks and Ebola and actually do kill more Americans! Yay, we got something right! Other than that it is literally reversed.)

Dying from a terrorist attack would be horrible; in addition to your own death you have all the other likely deaths and injuries, and the sheer horror and evil of the terrorist attack itself. Dying from Ebola would be almost as bad, with gruesome and agonizing symptoms. Dying of a shark attack would be still pretty awful, as you get dismembered alive. But dying in a car accident isn’t so bad; it’s usually over pretty quick and the event seems tragic but ordinary. And dying of heart disease and diabetes from your cheeseburger overdose will happen slowly over many years, you’ll barely even notice it coming and probably die rapidly from a heart attack or comfortably in your sleep. (Wasn’t that a pleasant paragraph? But there’s really no other way to make the point.)

If we try to estimate the probability at all—and I don’t think most people even bother—it isn’t by rigorous scientific research; it’s usually by availability heuristic: How many examples can you think of in which that event happened? If you can think of a lot, you assume that it happens a lot.

And that might even be reasonable, if we still lived in hunter-gatherer tribes or small farming villages and the 150 or so people you knew were the only people you ever heard about. But now that we have live TV and the Internet, news can get to us from all around the world, and the news isn’t trying to give us an accurate assessment of risk, it’s trying to get our attention by talking about the biggest, scariest, most exciting things that are happening around the world. The amount of news attention an item receives is in fact in inverse proportion to the probability of its occurrence, because things are more exciting if they are rare and unusual. Which means that if we are estimating how likely something is based on how many times we heard about it on the news, our estimates are going to be almost exactly reversed from reality. Ironically it is the very fact that we have more information that makes our estimates less accurate, because of the way that information is presented.

It would be a pretty boring news channel that spent all day saying things like this: “82 people died in car accidents today, and 1657 people had fatal heart attacks, 11.8 million had migraines, and 127 million played the lottery and lost; in world news, 214 countries did not go to war, and 6,147 children starved to death in Africa…” This would, however, be vastly more informative.

In the meantime, here are a couple of counter-heuristics I recommend to you: Don’t think about losses and gains, think about where you are and where you might be. Don’t say, “I’ll gain $1,000”; say “I’ll raise my income this year to $41,000.” Definitely do not think in terms of the percentage price of things; think in terms of absolute amounts of money. Cheap expensive things, expensive cheap things is a motto of mine; go ahead and buy the $5 toothbrush instead of the $1, because that’s only $4. But be very hesitant to buy the $22,000 car instead of the $21,000, because that’s $1,000. If you need to estimate the probability of something, actually look it up; don’t try to guess based on what it feels like the probability should be. Make this unprecedented access to information work for you instead of against you. If you want to know how many people die in car accidents each year, you can literally ask Google and it will tell you that (I tried it—it’s 1.3 million worldwide). The fatality rate of a given disease versus the risk of its vaccine, the safety rating of a particular brand of car, the number of airplane crash deaths last month, the total number of terrorist attacks, the probability of becoming a university professor, the average functional lifespan of a new television—all these things and more await you at the click of a button. Even if you think you’re pretty sure, why not look it up anyway?

Perhaps then we can make prospect theory wrong by making ourselves more rational.

How do we measure happiness?

JDN 2457028 EST 20:33.

No, really, I’m asking. I strongly encourage my readers to offer in the comments any ideas they have about the measurement of happiness in the real world; this has been a stumbling block in one of my ongoing research projects.

In one sense the measurement of happiness—or more formally utility—is absolutely fundamental to economics; in another it’s something most economists are astonishingly afraid of even trying to do.

The basic question of economics has nothing to do with money, and is really only incidentally related to “scarce resources” or “the production of goods” (though many textbooks will define economics in this way—apparently implying that a post-scarcity economy is not an economy). The basic question of economics is really this: How do we make people happy?

This must always be the goal in any economic decision, and if we lose sight of that fact we can make some truly awful decisions. Other goals may work sometimes, but they inevitably fail: If you conceive of the goal as “maximize GDP”, then you’ll try to do any policy that will increase the amount of production, even if that production comes at the expense of stress, injury, disease, or pollution. (And doesn’t that sound awfully familiar, particularly here in the US? 40% of Americans report their jobs as “very stressful” or “extremely stressful”.) If you were to conceive of the goal as “maximize the amount of money”, you’d print money as fast as possible and end up with hyperinflation and total economic collapse ala Zimbabwe. If you were to conceive of the goal as “maximize human life”, you’d support methods of increasing population to the point where we had a hundred billion people whose lives were barely worth living. Even if you were to conceive of the goal as “save as many lives as possible”, you’d find yourself investing in whatever would extend lifespan even if it meant enormous pain and suffering—which is a major problem in end-of-life care around the world. No, there is one goal and one goal only: Maximize happiness.

I suppose technically it should be “maximize utility”, but those are in fact basically the same thing as long as “happiness” is broadly conceived as eudaimoniathe joy of a life well-lived—and not a narrow concept of just adding up pleasure and subtracting out pain. The goal is not to maximize the quantity of dopamine and endorphins in your brain; the goal is to achieve a world where people are safe from danger, free to express themselves, with friends and family who love them, who participate in a world that is just and peaceful. We do not want merely the illusion of these things—we want to actually have them. So let me be clear that this is what I mean when I say “maximize happiness”.

The challenge, therefore, is how we figure out if we are doing that. Things like money and GDP are easy to measure; but how do you measure happiness?
Early economists like Adam Smith and John Stuart Mill tried to deal with this question, and while they were not very successful I think they deserve credit for recognizing its importance and trying to resolve it. But sometime around the rise of modern neoclassical economics, economists gave up on the project and instead sought a narrower task, to measure preferences.

This is often called technically ordinal utility, as opposed to cardinal utility; but this terminology obscures the fundamental distinction. Cardinal utility is actual utility; ordinal utility is just preferences.

(The notion that cardinal utility is defined “up to a linear transformation” is really an eminently trivial observation, and it shows just how little physics the physics-envious economists really understand. All we’re talking about here is units of measurement—the same distance is 10.0 inches or 25.4 centimeters, so is distance only defined “up to a linear transformation”? It’s sometimes argued that there is no clear zero—like Fahrenheit and Celsius—but actually it’s pretty clear to me that there is: Zero utility is not existing. So there you go, now you have Kelvin.)

Preferences are a bit easier to measure than happiness, but not by as much as most economists seem to think. If you imagine a small number of options, you can just put them in order from most to least preferred and there you go; and we could imagine asking someone to do that, or—the technique of revealed preferenceuse the choices they make to infer their preferences by assuming that when given the choice of X and Y, choosing X means you prefer X to Y.

Like much of neoclassical theory, this sounds good in principle and utterly collapses when applied to the real world. Above all: How many options do you have? It’s not easy to say, but the number is definitely huge—and both of those facts pose serious problems for a theory of preferences.

The fact that it’s not easy to say means that we don’t have a well-defined set of choices; even if Y is theoretically on the table, people might not realize it, or they might not see that it’s better even though it actually is. Much of our cognitive effort in any decision is actually spent narrowing the decision space—when deciding who to date or where to go to college or even what groceries to buy, simply generating a list of viable options involves a great deal of effort and extremely complex computation. If you have a true utility function, you can satisficechoosing the first option that is above a certain threshold—or engage in constrained optimizationchoosing whether to continue searching or accept your current choice based on how good it is. Under preference theory, there is no such “how good it is” and no such thresholds. You either search forever or choose a cutoff arbitrarily.

Even if we could decide how many options there are in any given choice, in order for this to form a complete guide for human behavior we would need an enormous amount of information. Suppose there are 10 different items I could have or not have; then there are 10! = 3.6 million possible preference orderings. If there were 100 items, there would be 100! = 9e157 possible orderings. It won’t do simply to decide on each item whether I’d like to have it or not. Some things are complements: I prefer to have shoes, but I probably prefer to have $100 and no shoes at all rather than $50 and just a left shoe. Other things are substitutes: I generally prefer eating either a bowl of spaghetti or a pizza, rather than both at the same time. No, the combinations matter, and that means that we have an exponentially increasing decision space every time we add a new option. If there really is no more structure to preferences than this, we have an absurd computational task to make even the most basic decisions.

This is in fact most likely why we have happiness in the first place. Happiness did not emerge from a vacuum; it evolved by natural selection. Why make an organism have feelings? Why make it care about things? Wouldn’t it be easier to just hard-code a list of decisions it should make? No, on the contrary, it would be exponentially more complex. Utility exists precisely because it is more efficient for an organism to like or dislike things by certain amounts rather than trying to define arbitrary preference orderings. Adding a new item means assigning it an emotional value and then slotting it in, instead of comparing it to every single other possibility.

To illustrate this: I like Coke more than I like Pepsi. (Let the flame wars begin?) I also like getting massages more than I like being stabbed. (I imagine less controversy on this point.) But the difference in my mind between massages and stabbings is an awful lot larger than the difference between Coke and Pepsi. Yet according to preference theory (“ordinal utility”), that difference is not meaningful; instead I have to say that I prefer the pair “drink Pepsi and get a massage” to the pair “drink Coke and get stabbed”. There’s no such thing as “a little better” or “a lot worse”; there is only what I prefer over what I do not prefer, and since these can be assigned arbitrarily there is an impossible computational task before me to make even the most basic decisions.

Real utility also allows you to make decisions under risk, to decide when it’s worth taking a chance. Is a 50% chance of $100 worth giving up a guaranteed $50? Probably. Is a 50% chance of $10 million worth giving up a guaranteed $5 million? Not for me. Maybe for Bill Gates. How do I make that decision? It’s not about what I prefer—I do in fact prefer $10 million to $5 million. It’s about how much difference there is in terms of my real happiness—$5 million is almost as good as $10 million, but $100 is a lot better than $50. My marginal utility of wealth—as I discussed in my post on progressive taxation—is a lot steeper at $50 than it is at $5 million. There’s actually a way to use revealed preferences under risk to estimate true (“cardinal”) utility, developed by Von Neumann and Morgenstern. In fact they proved a remarkably strong theorem: If you don’t have a cardinal utility function that you’re maximizing, you can’t make rational decisions under risk. (In fact many of our risk decisions clearly aren’t rational, because we aren’t actually maximizing an expected utility; what we’re actually doing is something more like cumulative prospect theory, the leading cognitive economic theory of risk decisions. We overrespond to extreme but improbable events—like lightning strikes and terrorist attacks—and underrespond to moderate but probable events—like heart attacks and car crashes. We play the lottery but still buy health insurance. We fear Ebola—which has never killed a single American—but not influenza—which kills 10,000 Americans every year.)

A lot of economists would argue that it’s “unscientific”—Kenneth Arrow said “impossible”—to assign this sort of cardinal distance between our choices. But assigning distances between preferences is something we do all the time. Amazon.com lets us vote on a 5-star scale, and very few people send in error reports saying that cardinal utility is meaningless and only preference orderings exist. In 2000 I would have said “I like Gore best, Nader is almost as good, and Bush is pretty awful; but of course they’re all a lot better than the Fascist Party.” If we had simply been able to express those feelings on the 2000 ballot according to a range vote, either Nader would have won and the United States would now have a three-party system (and possibly a nationalized banking system!), or Gore would have won and we would be a decade ahead of where we currently are in preventing and mitigating global warming. Either one of these things would benefit millions of people.

This is extremely important because of another thing that Arrow said was “impossible”—namely, “Arrow’s Impossibility Theorem”. It should be called Arrow’s Range Voting Theorem, because simply by restricting preferences to a well-defined utility and allowing people to make range votes according to that utility, we can fulfill all the requirements that are supposedly “impossible”. The theorem doesn’t say—as it is commonly paraphrased—that there is no fair voting system; it says that range voting is the only fair voting system. A better claim is that there is no perfect voting system, which is true if you mean that there is no way to vote strategically that doesn’t accurately reflect your true beliefs. The Myerson-Satterthwaithe Theorem is then the proper theorem to use; if you could design a voting system that would force you to reveal your beliefs, you could design a market auction that would force you to reveal your optimal price. But the least expressive way to vote in a range vote is to pick your favorite and give them 100% while giving everyone else 0%—which is identical to our current plurality vote system. The worst-case scenario in range voting is our current system.

But the fact that utility exists and matters, unfortunately doesn’t tell us how to measure it. The current state-of-the-art in economics is what’s called “willingness-to-pay”, where we arrange (or observe) decisions people make involving money and try to assign dollar values to each of their choices. This is how you get disturbing calculations like “the lives lost due to air pollution are worth $10.2 billion.”

Why are these calculations disturbing? Because they have the whole thing backwards—people aren’t valuable because they are worth money; money is valuable because it helps people. It’s also really bizarre because it has to be adjusted for inflation. Finally—and this is the point that far too few people appreciate—the value of a dollar is not constant across people. Because different people have different marginal utilities of wealth, something that I would only be willing to pay $1000 for, Bill Gates might be willing to pay $1 million for—and a child in Africa might only be willing to pay $10, because that is all he has to spend. This makes the “willingness-to-pay” a basically meaningless concept independent of whose wealth we are spending.

Utility, on the other hand, might differ between people—but, at least in principle, it can still be added up between them on the same scale. The problem is that “in principle” part: How do we actually measure it?

So far, the best I’ve come up with is to borrow from public health policy and use the QALY, or quality-adjusted life year. By asking people macabre questions like “What is the maximum number of years of your life you would give up to not have a severe migraine every day?” (I’d say about 20—that’s where I feel ambivalent. At 10 I definitely would; at 30 I definitely wouldn’t.) or “What chance of total paralysis would you take in order to avoid being paralyzed from the waist down?” (I’d say about 20%.) we assign utility values: 80 years of migraines is worth giving up 20 years to avoid, so chronic migraine is a quality of life factor of 0.75. Total paralysis is 5 times as bad as paralysis from the waist down, so if waist-down paralysis is a quality of life factor of 0.90 then total paralysis is 0.50.

You can probably already see that there are lots of problems: What if people don’t agree? What if due to framing effects the same person gives different answers to slightly different phrasing? Some conditions will directly bias our judgments—depression being the obvious example. How many years of your life would you give up to not be depressed? Suicide means some people say all of them. How well do we really know our preferences on these sorts of decisions, given that most of them are decisions we will never have to make? It’s difficult enough to make the actual decisions in our lives, let alone hypothetical decisions we’ve never encountered.

Another problem is often suggested as well: How do we apply this methodology outside questions of health? Does it really make sense to ask you how many years of your life drinking Coke or driving your car is worth?
Well, actually… it better, because you make that sort of decision all the time. You drive instead of staying home, because you value where you’re going more than the risk of dying in a car accident. You drive instead of walking because getting there on time is worth that additional risk as well. You eat foods you know aren’t good for you because you think the taste is worth the cost. Indeed, most of us aren’t making most of these decisions very well—maybe you shouldn’t actually drive or drink that Coke. But in order to know that, we need to know how many years of your life a Coke is worth.

As a very rough estimate, I figure you can convert from willingness-to-pay to QALY by dividing by your annual consumption spending Say you spend annually about $20,000—pretty typical for a First World individual. Then $1 is worth about 50 microQALY, or about 26 quality-adjusted life-minutes. Now suppose you are in Third World poverty; your consumption might be only $200 a year, so $1 becomes worth 5 milliQALY, or 1.8 quality-adjusted life-days. The very richest individuals might spend as much as $10 million on consumption, so $1 to them is only worth 100 nanoQALY, or 3 quality-adjusted life-seconds.

That’s an extremely rough estimate, of course; it assumes you are in perfect health, all your time is equally valuable and all your purchasing decisions are optimized by purchasing at marginal utility. Don’t take it too literally; based on the above estimate, an hour to you is worth about $2.30, so it would be worth your while to work for even $3 an hour. Here’s a simple correction we should probably make: if only a third of your time is really usable for work, you should expect at least $6.90 an hour—and hey, that’s a little less than the US minimum wage. So I think we’re in the right order of magnitude, but the details have a long way to go.

So let’s hear it, readers: How do you think we can best measure happiness?

The moral—and economic—case for progressive taxation

JDN 2456935 PDT 09:44.

Broadly speaking, there are three ways a tax system can be arranged: It can be flat, in which every person pays the same tax rate; it can be regressive, in which people with higher incomes pay lower rates; or it can be progressive, in which case people with higher incomes pay higher rates.

There are certain benefits to a flat tax: Above all, it’s extremely easy to calculate. It’s easy to determine how much revenue a given tax rate will raise; multiply the rate times your GDP. It’s also easy to determine how much a given person should owe; multiply the rate times their income. This also makes the tax withholding process much easier; a fixed proportion can be withheld from all income everyone makes without worrying about how much they made before or are expected to make later. If your goal is minimal bureaucracy, a flat tax does have something to be said for it.

A regressive tax, on the other hand, is just as complicated as a progressive tax but has none of the benefits. It’s unfair because you’re actually taking more from people who can afford the least. (Note that this is true even if the rich actually pay a higher total; the key point, which I will explain in detail shortly, is that a dollar is worth more to you if you don’t have very many.) There is basically no reason you would ever want to have a regressive tax system—and yet, all US states have regressive tax systems. This is mainly because they rely upon sales taxes, which are regressive because rich people spend a smaller portion of what they have. If you make $10,000 per year, you probably spend $9,500 (you may even spend $15,000 and rack up the difference in debt!). If you make $50,000, you probably spend $40,000. But if you make $10 million, you probably only spend $4 million. Since sales taxes only tax on what you spend, the rich effectively pay a lower rate. This could be corrected to some extent by raising the sales tax on luxury goods—say a 20% rate on wine and a 50% rate on yachts—but this is awkward and very few states even try. Not even my beloved California; they fear drawing the ire of wineries and Silicon Valley.

The best option is to make the tax system progressive. Thomas Piketty has been called a “Communist” for favoring strongly progressive taxation, but in fact most Americans—including Republicans—agree that our tax system should be progressive. (Most Americans also favor cutting the Department of Defense rather than Medicare. This then raises the question: Why isn’t Congress doing that? Why aren’t people voting in representatives to Congress who will do that?) Most people judge whether taxes are fair based on what they themselves pay—which is why, in surveys, the marginal rate on the top 1% is basically unrelated to whether people think taxes are too high, even though that one bracket is the critical decision in deciding any tax system—you can raise about 20% of your revenue by hurting about 1% of your people. In a typical sample of 1,000 respondents, only about 10 are in the top 1%. If you want to run for Congress, the implication is clear: Cut taxes on all but the top 1%, raise them enormously on the top 0.1%, 0.01%, and 0.001%, and leave the 1% the same. People will feel that you’ve made the taxes more fair, and you’ve also raised more revenue. In other words, make the tax system more progressive.

The good news on this front is that the US federal tax system is progressive—barely. Actually the US tax system is especially progressive over the whole distribution—by some measures the most progressive in the world—but the problem is that it’s not nearly progressive enough at the very top, where the real money is. The usual measure based on our Gini coefficient ignores the fact that Warren Buffett pays a lower rate than his secretary. The Gini is based on population, and billionaires are a tiny portion of the population—but they are not a tiny portion of the money. Net wealth of the 400 richest people (the top 0.0001%) adds up to about $2 trillion (13% of our $15 trillion GDP, or about 4% of our $54 trillion net wealth). It also matters of course how you spend your tax revenue; even though Sweden’s tax system is no more progressive than ours and their pre-tax inequality is about the same, their spending is much more targeted at reducing inequality.

Progressive taxation is inherently more fair, because the value of a dollar decreases the more you have. We call this diminishing marginal utility of wealth. There is a debate within the cognitive economics literature about just how quickly the marginal utility of wealth decreases. On the low end, Easterlin argues that it drops off extremely fast, becoming almost negligible as low as $75,000 per year. This paper is on the high end, arguing that marginal utility decreases “only” as the logarithm of how much you have. That’s what I’ll use in this post, because it’s the most conservative reasonable estimate. I actually think the truth is somewhere in between, with marginal utility decreasing about exponentially.

Logarithms are also really easy to work with, once you get used to them. So let’s say that the amount of happiness (utility) U you get from an amount of income I is like this: U = ln(I)

Now let’s suppose the IRS comes along and taxes your money at a rate r. We must have r < 1, or otherwise they’re trying to take money you don’t have. We don’t need to have r > 0; r < 0 would just mean that you receive more in transfers than you lose in taxes. For the poor we should have r < 0.

Now your happiness is U = ln((1-r)I).

By the magic of logarithms, this is U = ln(I) + ln(1-r).

If r is between 0 and 1, ln(1-r) is negative and you’re losing happiness. (If r < 0, you’re gaining happiness.) The amount of happiness you lose, ln(1-r), is independent of your income. So if your goal is to take a fixed amount of happiness, you should tax at a fixed rate of income—a flat tax.

But that really isn’t fair, is it? If I’m getting 100 utilons of happiness from my money and you’re only getting 2 utilons from your money, then taking that 1 utilon, while it hurts the same—that’s the whole point of utility—leaves you an awful lot worse off than I. It actually makes the ratio between us worse, going from 50 to 1, all the way up to 99 to 1.

Notice how if we had a regressive tax, it would be obviously unfair—we’d actually take more utility from poor people than rich people. I have 100 utilons, you have 2 utilons; the taxes take 1.5 of yours but only 0.5 of mine. That seems frankly outrageous; but it’s what all US states have.

Most of the money you have is ultimately dependent on your society. Let’s say you own a business and made your wealth selling products; it seems like you deserve to have that wealth, doesn’t it? (Don’t get me started on people who inherited their wealth!) Well, in order to do that, you need to have strong institutions of civil government; you need security against invasion; you need protection of property rights and control of crime; you need a customer base who can afford your products (that’s our problem in the Second Depression); you need workers who are healthy and skilled; you need a financial system that provides reliable credit (also a problem). I’m having trouble finding any good research on exactly what proportion of individual wealth is dependent upon the surrounding society, but let’s just say Bill Gates wouldn’t be spending billions fighting malaria in villages in Ghana if he had been born in a village in Ghana. It doesn’t matter how brilliant or determined or hard-working you are, if you live in a society that can’t support economic activity.

In other words, society is giving you a lot of happiness you wouldn’t otherwise have. Because of this, it makes sense that in order to pay for all that stuff society is doing for you (and maintain a stable monetary system), they would tax you according to how much happiness they’re giving you. Hence we shouldn’t tax your money at a constant rate; we should tax your utility at a constant rate and then convert back to money. This defines a new sort of “tax rate” which I’ll call p. Like our tax rate r, p needs to be less than 1, but it doesn’t need to be greater than 0.

Of the U = ln(I) utility you get from your money, you will get to keep U = (1-p) ln(I). Say it’s 10%; then if I have 100 utilons, they take 10 utilons and leave me with 90. If you have 2 utilons, they take 0.2 and leave you with 1.8. The ratio between us remains the same: 50 to 1.

What does this mean for the actual tax rate? It has to be progressive. Very progressive, as a matter of fact. And in particular, progressive all the way up—there is no maximum tax bracket.

The amount of money you had before is just I.

The amount of money you have now can be found as the amount of money I’ that gives you the right amount of utility. U = ln(I’) = (1-p) ln(I). Take the exponential of both sides: I’ = I^(1-p).

The units on this are a bit weird, “dollars to the 0.8 power”? Oddly, this rarely seems to bother economists when they use Cobb-Douglas functions which are like K^(1/3) L^(2/3). It bothers me though; to really make this tax system in practice you’d need to fix the units of measurement, probably using some subsistence level. Say that’s set at $10,000; instead of saying you make $2 million, we’d say you make 200 subsistence levels.

The tax rate you pay is then r = 1 – I’/I, which is r = 1 – I^-p. As I increases, I^-p decreases, so r gets closer and closer to 1. It never actually hits 1 (that would be a 100% tax rate, which hardly anyone thinks is fair), but for very large income is does get quite close.

Here, let’s use some actual numbers. Suppose as I said we make the subsistence level $10,000. Let’s also set p = 0.1, meaning we tax 10% of your utility. Then, if you make the US median individual income, that’s about $30,000 which would be I = 3. US per-capita GDP of $55,000 would be I = 5.5, and so on. I’ll ignore incomes below the subsistence level for now—basically what you want to do there is establish a basic income so that nobody is below the subsistence level.

I made a table of tax rates and after-tax incomes that would result:

Pre-tax income Tax rate After-tax income
$10,000 0.0% $10,000
$20,000 6.7% $18,661
$30,000 10.4% $26,879
$40,000 12.9% $34,822
$50,000 14.9% $42,567
$60,000 16.4% $50,158
$70,000 17.7% $57,622
$80,000 18.8% $64,980
$90,000 19.7% $72,247
$100,000 20.6% $79,433
$1,000,000 36.9% $630,957
$10,000,000 49.9% $5,011,872
$100,000,000 60.2% $39,810,717
$1,000,000,000 68.4% $316,227,766

What if that’s not enough revenue? We could raise to p = 0.2:

Pre-tax income Tax rate After-tax income
$10,000 0.0% $10,000
$20,000 12.9% $17,411
$30,000 19.7% $24,082
$40,000 24.2% $30,314
$50,000 27.5% $36,239
$60,000 30.1% $41,930
$70,000 32.2% $47,433
$80,000 34.0% $52,780
$90,000 35.6% $57,995
$100,000 36.9% $63,096
$1,000,000 60.2% $398,107
$10,000,000 74.9% $2,511,886
$100,000,000 84.2% $15,848,932
$1,000,000,000 90.0% $100,000,000

The richest 400 people in the US have a combined net wealth of about $2.2 trillion. If we assume that billionaires make about a 10% return on their net wealth, this 90% rate would raise over $200 billion just from those 400 billionaires alone, enough to pay all interest on the national debt. Let me say that again: This tax system would raise enough money from a group of people who could fit in a large lecture hall to provide for servicing the national debt. And it could do so indefinitely, because we are only taxing the interest, not the principal.

And what if that’s still not enough? We could raise it even further, to p = 0.3. Now the tax rates look a bit high for most people, but not absurdly so—and notice how the person at the poverty line is still paying nothing, as it should be. The millionaire is unhappy with 75%, but the billionaire is really unhappy with his 97% rate. But the government now has plenty of money.

Pre-tax income Tax rate After-tax income
$10,000 0.0% $10,000
$20,000 18.8% $16,245
$30,000 28.1% $21,577
$40,000 34.0% $26,390
$50,000 38.3% $30,852
$60,000 41.6% $35,051
$70,000 44.2% $39,045
$80,000 46.4% $42,871
$90,000 48.3% $46,555
$100,000 49.9% $50,119
$1,000,000 74.9% $251,189
$10,000,000 87.4% $1,258,925
$100,000,000 93.7% $6,309,573
$1,000,000,000 96.8% $31,622,777

Is it fair to tax the super-rich at such extreme rates? Well, why wouldn’t it be? They are living fabulously well, and most of their opportunity to do so is dependent upon living in our society. It’s actually not at all unreasonable to think that over 97% of the wealth a billionaire has is dependent upon society in this way—indeed, I think it’s unreasonable to imagine that it’s any less than 99.9%. If you say that the portion a billionaire receives from society is less than 99.9%, you are claiming that it is possible to become a millionaire while living on a desert island. (Remember, 0.1% of $1 billion is $1 million.) Forget the money system; do you really think that anything remotely like a millionaire standard of living is possible from catching your own fish and cutting down your own trees?Another fun fact is that this tax system will not change the ordering of income at all. If you were the 37,824th richest person yesterday, you will be the 37,824th richest person today; you’ll just have a lot less money while you do so. And if you were the 300,120,916th richest person, you’ll still be the 300,120,916th person, and probably still have the same amount of money you did before (or even more, if the basic income is doled out on tax day).

And these figures, remember, are based on a conservative estimate of how quickly the marginal utility of wealth decreases. I’m actually pretty well convinced that it’s much faster than that, in which case even these tax rates may not be progressive enough.

Many economists worry that taxes reduce the incentive to work. If you are taxed at 30%, that’s like having a wage that’s 30% lower. It’s not hard to imagine why someone might not work as much if they were being paid 30% less.

But there are actually two effects here. One is the substitution effect: a higher wage gives you more reason to work. The other is the income effect: having more money means that you can meet your needs without working as much.

For low incomes, the substitution effect dominates; if your pay rises from $12,000 a year to $15,000, you’re probably going to work more, because you get paid more to work and you’re still hardly wealthy enough to rest on your laurels.

For moderate incomes, the effects actually balance quite well; people who make $40,000 work about the same number of hours as people who make $50,000.

For high incomes, the income effect dominates; if your pay rises from $300,000 to $400,000, you’re probably going to work less, because you can pay all your bills while putting in less work.

So if you want to maximize work incentives, what should you do? You want to raise the wages of poor people and lower the wages of rich people. In other words, you want very low—or negative—taxes on the lower brackets, and very high taxes on the upper brackets. If you’re genuinely worried about taxes distorting incentives to work, you should be absolutely in favor of progressive taxation.

In conclusion: Because money is worth less to you the more of it you have, in order to take a fixed proportion of the happiness, we should be taking an increasing proportion of the money. In order to be fair in terms of real utility, taxes should be progressive. And this would actually increase work incentives.