Econ 522 – Fall 2009 – Lecture 24 Today’s material is not on the final Pretty much everything we’ve done this semester has assumed that people are perfectly rational, and respond to incentives according to what they correctly perceive to be their own best-interest. Property and nuisance law: people can bargain with each other to get entitlements to the owners who value them most Contract law: parties can negotiate efficient contracts, courts can enforce them correctly Tort law: people react rationally to incentives; courts can assign liability and damages correctly Criminal law: even criminals react rationally to incentives, commit crimes when benefit outweighs expected costs These are strong assumptions They are very useful assumptions o they gave us a lot of predictions about how laws would affect behavior, and therefore what laws would lead to efficiency But the question remains whether they’re valid assumptions. Today’s topic: How these assumptions sometimes fail in real life And therefore, why we may want to be skeptical about some of the semester’s conclusions But you’re still being tested on those conclusions come Sunday Think of today is a tangential detour off of the main material -1- In the last decade or two, there’s been huge growth in the field of behavioral economics Behavioral economics studies how peoples’ actual behavior differs from the predictions of the standard model We mentioned a couple examples over the course of the semester o for example, we mentioned that people don’t react to probabilistic risks the way expected-utility theory would suggest. Behavioral economics started out as a fairly ad-hoc discipline someone would pick a prediction of the standard model o for instance, expected-utility-maximizing under uncertainty o or discounting future payoffs by a constant per-period discount rate o or maximizing only one’s own payoff in a multi-player setting then they would do experiments o have a bunch of undergraduates play games in a lab or look for instances in the real world where the prediction was violated. Over time, behavioral economics has generated some fairly robust conclusions systematic ways in which peoples’ behavior differs from the standard model of perfect rationality. What’s important is that the way peoples’ behavior deviates from the standard predictions is not random If it was, we could explain it simply as random errors o people aren’t necessarily infinitely wise, so they sometimes make mistakes in calculating the right behavior o and these mistakes can go in any direction Instead, we find that peoples’ behavior seems to have consistent biases o that is, in many situations, deviations from perfect rationality all seem to go in the same direction At its best, behavioral economics also holds itself to a sort of a “higher standard” than traditional economics Traditional economics makes assumptions (basically, rationality and optimization), derives predictions, and then asks whether the predictions seem to be right, but doesn’t spend that much time questioning the assumptions themselves Behavioral economics tries to justify the assumptions as well. -2- (A couple recent “pop economics” books if you’re interested in behavioral economics in general: “Predictably Irrational,” by Dan Ariely; and “Nudge,” by Richard Thaler.) “Behavioral Law and Economics”, edited by Cass Sunstein. First chapter is the paper on the syllabus, Jolls, Sunstein, and Thaler, “A Behavioral Approach to Law and Economics.” It discusses some of these biases observed by behavioral economists; and proposes how these more complicated (and therefore more accurate) views of human behavior could be incorporated into law and economics. Earlier in the semester, we distinguished between positive and normative economics. Jolls, Sunstein, and Thaler discuss three different “uses” for economics (or law and econ); behavioral economics has implications for each of these. The positive part o “Positive” sometimes means “descriptive”, but here it means “predictive” – making predictions about how people will respond to particular laws o The positive approach also allows us to predict (or explain) the laws that do exist – as outcomes of some process (either the common law “evolving” toward efficiency, as we’ve discussed in class; or as the outcome of a legislative process) o (Positive statements are things like, “an increase in expected punishment will lead to a decrease in crime”) The prescriptive part o Once we know how people react to a given law, we can make prescriptions about how the law should be designed to achieve particular goals o (Prescriptive statements are things like, “to achieve efficiency, the law should specify injunctive relief when transaction costs are low, and damages when transaction costs are high”) o If people behave differently than the standard model, than the law should be designed to take this into account The normative part o The normative question is, what should the goal of the legal system be? o Throughout this class, we’ve mostly assumed that the goal of the law is economic efficiency – we gave a number of arguments to defend this o This gets much trickier when a behavioral approach is used o One of the observations of behavioral economics is that peoples’ preferences are not as well-defined and stable as the standard model assumes o But this makes even measuring efficiency hard, since we don’t know what preferences to use An example: one of the findings of behavioral economics is that people value things more once they have them -3- So if I gave one of you a chocolate bar, you might get all excited about it, and be more hurt by losing it than if you hadn’t had it to begin with Suppose I give one of you a chocolate bar, and offer you an opportunity to sell it to someone else Good chance you wouldn’t Even if I offered to subsidize the purchase – I’d throw in 50 cents on top of what they pay you – you might not So we’d conclude you value the chocolate bar more than them. But if we’d started out giving the chocolate bar to them, maybe they wouldn’t have wanted to sell it to you either. o But this muddles the question of who values it more: if I give it to you, you value it more than him; if I give it to him, he values it more than you. But now we have no way to gauge which allocation is efficient!) So that’s the goal of behavioral law and economics – to give a more accurate model of how people actually behave, and use that model to reconsider the positive, prescriptive, and normative conclusions of law and economics. The Jolls, Sunstein and Thaler paper concedes that so far, the results are fairly sparse the paper reads more like a proposal for future research than a bunch of conclusions Still, some of the initial results – basically, taking behavioral biases documented elsewhere and considering their implications for law and economics – are quite interesting. -4- Behavioral biases – the way peoples’ actual behavior deviates from the standard model of perfect self-interested rationality – are generally broken up into three categories: Bounded rationality o People aren’t perfect – we have limited computational abilities, have flawed memory, imperfect powers of perception o This leads us to make “mistakes” o It also leads us to use simple “rules of thumb”, rather than detailed analysis, in many situations Bounded willpower o Even when we know what’s “right”, we don’t always do it we eat too much we don’t go to the gym often enough we have trouble quitting smoking o This means that commitment devices – finding a way to “give up” options – can have value, which doesn’t make sense in the standard model We’ve all seen people turn down leftover cake – “if I have it at home, I’ll eat it, and I don’t want to eat it.” (This explains savings plans that “force” people to save, or gym memberships that reward you for actually going to the gym) Bounded self-interest o People aren’t completely selfish – we all do nice things for other people. o But even in anonymous situations with strangers, people tend to care about others’ outcomes as well as their own – we’ll see examples. -5- On to some examples. We begin with an experiment done at Cornell. The experiment took 44 students in an advanced undergrad Law and Econ class, and gave half of them tokens Each person – both those who got tokens and those who didn’t – was also given a personal value, an amount of money they could exchange a token for at the end of class if they have one Then people were given an opportunity to trade. The market for tokens worked just like the standard model would predict o people with higher token values bought them from people with lower token values But that was with tokens, which had an artificial value that everyone knew objectively So they reran the experiment This time, half the class was chosen at random and given Cornell coffee mugs Then students were allowed to trade. If, like in the standard model, each person knew exactly what a mug was worth to them, we’d predict about half the mugs would trade hands o Since the people who got them were chosen at random, about half the mugs should have gone to people who valued them above the median valuation, and half to people who valued them below that o that latter half should all have been sold, to the people with high valuations who didn’t get mugs Instead, only 15% of the mugs traded hands And on average, people who got mugs asked more than twice as much money for them as the people who didn’t get them were willing to pay And the effect didn’t go away if the experiment was repeated. The conclusion was that having something makes you value it more – this is referred to as an endowment effect In this case, being given a mug made you value a mug more highly -6- The next question: so what? Well, the big “so what” is that this seems to contradict Coase Coase predicted that without transaction costs, the initial allocation should not affect the final allocation – whoever starts out with an object (or an entitlement), it will naturally flow to whoever values it the most But endowment effects mean that the initial allocation does matter, in terms of predicting the final allocation And if preferences really change depending on whether you got the object, it becomes very unclear how to even define efficiency! Recall what we said about injunctive relief in nuisance cases We argued that when transaction costs are small, injunctions would work well, since they clarify the two sides’ threat points so they can bargain to an efficient outcome Endowment effects challenge this result – they say that whoever is allocated the right initially, comes to value it more, and therefore may not be willing to give it away, regardless of who efficiency would have favored ex ante. The existence of this bias is fairly robust One of the chapters in Sunstein’s book, “Behavioral Law and Economics,” documents twelve different studies where peoples’ Willingness to Pay for something they didn’t have was compared to their Willingness to Accept an offer for something they did In every case, the payment required to give up something they had was greater – typically three times greater or more – than their willingness to pay o (example: willingness to pay to preserve natural resources) This also has implications for calculating damages If you asked someone ahead of time how much money they would accept to lose an arm, the number would be huge If someone lost an arm, and you asked them how much money it would take to make them overall as well-off as before, the number would be smaller. o This may partly be due to the fact that people adapt to new circumstances better than they anticipate o That is, if someone loses their arm, they find ways of dealing with it which make it less bad than they would have guessed ahead of time o Again, though, this calls into question which measure should be used in assessing efficiency o Suppose someone with two arms thinks losing one would be a catastrophe, on the order of a $10,000,000 loss o Someone who lost an arm realizes that life’s still not that bad, and that the damage done was, say, $500,000 o Is it efficient for a construction firm to take precautions that cost $3,000,000 to prevent each lost arm? -7- Another bias in how people evaluate options: context dependence Basically, how you choose between different options may depend on what else you’re considering Example: the attractiveness of a “compromise” solution o Suppose you’re deciding whether to buy a basic, $100 digital camera or keep using the one you’ve got o If there’s another option – a fancier camera for $500 – it makes the $100 camera seem like a better deal, and might make you more likely to buy it! There’s also a well-documented “second-cheapest wine effect” o (see http://www.mentalfloss.com/blogs/archives/18811 for example) Another bias Jolls/Sunstein/Thaler discuss is hindsight bias (mentioned earlier) Once something happens, people have trouble assessing what its likelihood was before the fact Specifically, they overestimate what the ex-ante probability was, once they know that the thing did in fact happen o Think back to one year before the election, and guess what the odds were at the time that Obama would be elected o Since it happened, it seems very likely o But in November 2007, Intrade had Obama as about 7% likely to win Why does this matter? Determining negligence usually requires figuring out what the probability was that something would happen, after it happens A storage company decides the risk of a fire at its warehouse is 1 in 1000, and so it doesn’t install a $10,000 sprinkler system to protect $1,000,000 in stored goods Now a fire occurs, and the jury has to sort out whether the company was negligent Knowing the fire occurred, the jury might decide the probability of a fire was 1 in 50, and find the company liable. o The same thing happens in lawsuits against publicly-owned companies who failed to disclose a particular risk to investors o Was the risk material, so the company was fraudulent in hiding it? o Or was it an extremely small risk that just happened to occur, so the company did its job and got unlucky? -8- The effect of hindsight bias should be clear: juries will find negligence more often than they would if they could perfectly assess ex-ante probabilities after the fact The proposals Jolls/Sunstein/Thaler give for dealing with hindsight bias, though, have problems themselves. o One thing they suggest is in some cases, to keep the jury in the dark about what happened o Obviously, since they were asked to serve on a jury, the jury knows something bad happened o However, in some cases, either action or lack of action would entail risk: treating a patient with a risky drug might cause them to die, but not giving them the drug might also cause them to die o They suggest the jury could be given the facts available at the time, without being told what choice was made, and asked to decide if either action would have constituted negligence o Still, this won’t always work, since in many cases the jury will be able to infer what happened from the fact that there’s a trial at all o and in order to make this work, the jury would have to not read newspapers or know anything about the trial, and not even know which lawyers represented the plaintiff and which ones represented the defendant! The other suggestion they make is to raise the standard of proof for finding negligence – from “preponderance of the evidence,” interpreted as 51% certainty, to, say, the “clear and convincing evidence” standard, generally interpreted as 6070% certainty But this assumes that hindsight bias is of a certain magnitude, not just that it exists; and that the “preponderance of the evidence” standard would be efficient if there were no hindsight bias. -9- Another bias they consider is what they call “self-serving bias”. This can be thought of as relative optimism that exists even when both sides have the same information. In another experiment they cite, students – undergrads and law students – were randomly assigned to the roles of plaintiff and defendant, knowing they would be asked to negotiate a settlement They were all given the same facts – based on an actual case in Texas Prior to negotiations, they were each asked to write down a guess as to the damages the judge actually awarded, as well as what they felt was a “fair” settlement – these answers would not be used in any way during the negotiations. Although they were chosen randomly, the students chosen to represent the plaintiffs guessed $14,500 higher than those representing the defendants as to the judge’s actual award, and answered $17,700 higher when asked for a “fair” settlement. (They give another example where the presidents of teachers unions and the presidents of school boards were asked what other cities were “comparable” to their own, since comparables were often brought up during salary negotiations. Not surprisingly, the union presidents listed cities with higher average salaries than those listed by school board presidents.) What does self-serving bias suggest? That pre-trial settlements may not happen as often as the standard model would predict And that sharing information won’t necessarily solve the problem That is, even if both sides have access to all the same information, they may still be relatively optimistic about their chances at trial, and therefore unable to reach a settlement (It also has implications for wage negotiations and strikes.) (Another example of self-serving bias is the old cliché that 80% of people think they’re above-average drivers. The authors mention that this sort of bias can be helpful in designing public campaigns that are more effective. In promoting safe driving, the move from “drive carefully or you’ll cause an accident” to “drive carefully, there are bad drivers out there you have to avoid!”) - 10 - There’s another bias, similar to hindsight bias, in how people perceive the probabilities of events. People tend to overestimate the probability of a certain type of accident happening in the future if they’ve recently observed a similar accident. Jolls/Sunstein/Thaler refer to this as availability – a memory of a recent accident is available in your mind, and colors your perception Adding to this is salience – basically, how vivid the memory is. So if you recently passed a car accident while driving, you tend to overestimate the likelihood of car accidents. If you just saw a news item about lead in toys, or asbestos in ceilings, you overestimate that risk. Jolls/Sunstein/Thaler use this to explain environmental and safety regulations covering whatever that year’s “hot topic” is, without regard for thoughtful costbenefit analysis (Recall that we say the “cost per life saved” of safety regulations varying from $200,000 to over a hundred million or even billions of dollars.) The problem of perception is made worse, they point out, by the fact that some people – politicians, or regulators, or concerned citizens who are worried about a problem – may deliberately try to keep the accident available, in order to gain from it They use the term “availability entrepreneurs” for people who try to whip everyone into a panic about a particular risk, presumably for private gain. (Think of most politicians in this country after 9/11.) They use Superfund – the EPA project for dealing with abandoned toxic waste dumps, passed after the Love Canal scare despite the actual risk being very small. But a recent example was available, and very salient, so there was no opposition) - 11 - Another example of bounded rationality, which may explain bounded willpower, is how people discount the future Peoples’ choices (both in the “real world” and in experiments) do reflect discounting of future events But the way they discount them is different from the theory The dropoff between “now” and “later” is much more severe than the dropoff between “some future time” and “some later future time” That is, the difference in value between something happening now versus a year from now is much greater than the difference between something happening in five years versus ten years. One implication is something we’ve already seen: that the last few years of a prison sentence offer much less deterrence than the first year Studies with criminals found that a five-year prison term was viewed as only being about twice as severe as a one-year term – the first year mattered far more, since it starts now (Also suggests people won’t save enough for retirement, etc.) The final bias they talk about is bounded self-interest. A standard example of this is the ultimatum game Player 1 is given the opportunity to propose a way to divide up $10 between himself and player 2 They player 2 says yes or no If he says yes, they each get their share; if he says no, they both get nothing. If player 2 is fully rational, he should say yes to any share of the money – even a penny is better than nothing Experiments find that people reject small offers – offers of less than a third of the total are often rejected This, and other evidence, brings Jolls/Sunstein/Thaler to the following conclusions, which are shocking to economists and completely obvious to everyone else: o people are willing to sacrifice their own material well-being to help those who are being kind o people are willing to sacrifice their own material well-being to punish those who are being unkind (The same observations occur in experimental Prisoner’s Dilemma-type games, and in lots of other settings.) - 12 - One interpretation is that people care not only about their outcome, but on whether it’s fair. o However, “fairness” is not defined objectively – that is, people don’t reject every offer below 50% They say that this preference for fairness may help explain lots of rules we see empirically: o rules against scalping tickets in many states o rules against predatory pricing during emergencies o rules against usury (unreasonably high interest rates) Standard economics would suggest these rules are inefficient o any voluntary transaction should be Pareto-improving, and these rules prohibit such transactions However, in each of these cases, prices appear to be “unfair” relative to an available market benchmark. We discussed earlier that the law may evolve toward greater efficiency Another common model (one that we did not consider) is that the law will evolve to favor certain wealthy or politically-connected individuals, since they can influence the political process and impose their own interests on the system. Jolls/Sunstein/Thaler suggest a third possibility: the law may evolve toward agreeing with peoples’ notion of “fairness” (either because legislators themselves share this preference, or because they think it will help them win re-election.) (This also explains why ticket prices are kept at a level low enough for there to be excess demand o one New York theater owner explained, “Even though we could sell tickets at $100, we’d be cutting our own throats because it would be a P.R. disaster for Broadway.” o Similarly, why stores don’t raise prices on popular toys that are likely to sell out during the Christmas rush. o Also: failed personalized pricing program on Amazon; failed weathersensitive Coke machines.) Most of the interesting work in the paper has been on the positive questions – how to more accurately describe peoples’ behavior They’re weaker on the prescriptive part – how to design the law to deal with it – presumably because when behavior is different in different situations, it’s hard to come up with general rules that always work. - 13 - One thing they point out is that how people respond to information depends very much on how it’s presented. They give an example: university staff choosing whether to invest their retirement money in a safe fund (bonds) or a risky one (stocks) Those who were shown a distribution of one-year returns of the stock fund focused on the volatility, and put most of their money in bonds Others were shown a simulated distribution of thirty-year returns, based on the same data; they focused more on the compounding effect of time, and put most of their money in stocks. The authors’ takeaway seems to be that when the government is putting out information – either to help people make informed choices, or to encourage or discourage particular behavior – it should think about how the “framing” matters Particularly in the second case – trying to push people to behave in a certain way – they can control the effect of the message by manipulating how it’s presented. o We saw earlier the example of safe-driving ads focusing on other drivers being bad, not you o They give other examples – particularly graphic warnings about cigarette dangers, phrasing things as losses instead of gains (“if you fail to do a breast self-examination, you will have a decreased chance of finding a tumor at an early stage”) instead of positives, etc They do a little bit on criminal stuff, but nothing we haven’t already seen. They wrap up with an argument for “anti-antipaternalism” Antipaternalism is the notion that the government shouldn’t tell people to do, since people know what makes them better off and can do it on their own They stop short of actually being pro-paternalism, for several reasons – among them, any behavioral bias that leads individuals to make mistakes, might also lead government bureaucrats to make the same mistakes when telling people what to do but they argue that we at least shouldn’t automatically reject paternalism, as it may have a role in some instances. If you’re interested, the article is on the syllabus, and cites tons of papers addressing particular biases in particular instances. The book by Sunstein, “Behavioral Law and Economics,” is a collection of some of these articles; I have it, if anyone wants a look. - 14 - There’s one other thing I thought I’d talk about today We saw on Tuesday that the optimal criminal system will not detect and punish every single crime This is for two reasons First, some crimes may actually be efficient, although this may be pretty rare And second, when the cost of deterrence is positive, it’s simply not worth paying enough to deter every crime However, we still assumed that most crimes are inefficient, and the only reason not to punish them is the practical – it would be too costly However, there are actually a lot of old laws still on the books in many states that seem pretty inefficient, or, you know, stupid One example: I grew up in Massachusetts, where you can’t buy booze on Sundays (Bars are open, but liquor stores are closed, and the beer cases at supermarkets is locked from 11 Saturday night until Monday morning) In many cases, laws were passed a long time ago, when times were different, and for whatever reason, they’re still on the books In that case, the law is enforced, and we just had to find a way around it – by planning ahead and buying more beer on Saturdays But there’s a great article I found on Slate last fall by Tim Wu, about a number of laws that are on the books but that we, as a society, have basically decided not to enforce at all The article is titled “American Lawbreaking” http://www.slate.com/id/2175730/entry/2175733/ - 15 - Wu starts off with a story of New York prosecutors sitting around the office, picking a celebrity – say, Mother Theresa – and trying to come up with a crime they could have charged her with Wu points out: “Full enforcement of every last law on the books would put all of us in prison for crimes such as “injuring a mail bag.” No enforcement of our laws, on the other hand, would mean anarchy. Somehow, officials must choose what laws really matter.” He continues: Tolerated lawbreaking is almost always a response to a political failure – the inability of our political institutions to adapt to social change or reach a rational compromise that reflects the interests of the nation and all concerned parties. That’s why the American statutes are full of laws that no one wants to see fully enforced – or even enforced at all. The rest of the article gives examples. The first example doesn’t exactly fit his premise, but it’s interesting anyway His claim: “over the last two decades, the pharmaceutical industry has developed a full set of substitutes for just about every illegal narcotic we have.” That is, rather than trying to legalize street drugs – which some people argue for, but which isn’t politically very popular – our society has developed drugs like Ritalin, vicodin, oxycontin, and clonazepam, which may serve a “legitimate” medical purpose in some instances, but also mimic the highs of cocaine or others (In the case of marijuana, there have also been a number of cities whose police chiefs, or district attorneys, have basically announced they won’t prosecute simple possession because it’s “not a priority”) - 16 - The second example Wu gives is pornography. Apparently, there’s porn online And pretty much all of it is illegal. Federal law prohibits using a “computer service” to transport over state lines “any obscene, lewd, lascivious, or filthy book, pamphlet, picture, motion-picture film, paper, letter, writing, print, or other matter of indecent character.” Wu discusses some of the history of pornography prosecution In 1968, Congress set up a commission to look into the “shocking” problem The commission came back with the recommendation that we repeal all obscenity laws, and replace them with laws to protect children and control public display (Basically, they felt, porn wasn’t a problem, as long as it was kept at home and away from kids) But when the report came out, President Nixon and other politicians condemned it as “morally bankrupt” and insisted they would continue the war on smut In the 1970s and 1980s, there were some well-publicized pornography prosecutions But they basically halted in the 1990s, and haven’t come back In 2005, new Attorney General Alberto Gonzalez tried to pressure local prosecutors to crack down on pornography. Basically, nothing happened – a few cases were brought which involved “extreme” content, but no prosecutions of mainstream pornography at all. Quoting a Miami attorney: “compared to terrorism, public corruption, and narcotics, [pornography] is no worse than dropping gum on the sidewalk.” Even though it’s still technically illegal, what’s actually developed is a sort of unofficial zoning system Rather than prohibiting the behavior, it’s regulated Not literally regulated; but it’s prosecuted when it crosses certain lines, and ignored otherwise Recall the Super Bowl wardrobe malfunction – just because everyone accepts that pornography is pseudo-legal, doesn’t mean they don’t freak out when it happens on prime-time network TV Prosecutors still chase down child pornographers and a few other extreme cases that cross certain lines. But “mainstream” porn is never prosecuted, and is therefore functionally legal - 17 - What’s interesting is not that modern society has basically legalized pornography, but the way it’s happened: o not through legislation or the court system, but through a general consensus – among prosecutors, the FCC, the FBI, and local police – to do nothing about it. o (The ironic part of this, of course, is that since it’s still illegal, it’s not regulated at all.) o (Also, I believe that at least up till a few years ago, oral sex was still illegal in about half of U.S. states. Again, not much enforcement.) Wu also discusses copyright law and illegal immigration, but the other one I found interesting was how the Amish and Mormons basically became exempt from many laws. The Amish refuse to pay Social Security taxes, and do not accept Social Security benefits; they will not educate their children beyond eighth grade To some degree, polygamy is still practiced among some Mormons Wu gives some history of the legal treatment of these groups: occasional prosecutions, then backlash, and how we seem to have reached a sort of truce: the Amish (and some Mormons) keep to themselves and keep quiet about what they’re doing, and the rest of society pretty much lets them be, not worrying about the fact that they’re breaking certain laws Again, there is a de facto zoning system. When a Mormon polygamist went on Sally Jessy Raphael and Jerry Springer to discuss and defend his lifestyle, he was tried and convicted. When it’s done quietly, in scattered communities outside of big cities, polygamy apparently still goes on, and is tolerated. (The Amish are quite open about how they live, but mostly keep to themselves, and nobody seems to worry much about it) - 18 - These all don’t fit that neatly into our usual framework of criminal law That is, we assume that crimes are crimes because society wants them to be crimes In these cases, society seems not to care whether certain things are crimes, but also not care enough to make them legal Or, you could argue, the political system is “broken” enough that certain things can’t be fixed, and so we adapt to that by ignoring certain laws that everyone agrees are silly An even more obvious example: speeding Most freeways in California have speed limits of 65 Most drivers go 80 I once got pulled over going 85, and the policeman told me, “Keep it around 80 and everyone’s happy” Roads are better than they used to be, cars are better than they used to be o maybe 65 used to be the optimal speed limit, but isn’t anymore o but it’s easier to just not enforce it that tightly than to actually change it So what was my point today? Throughout the semester, we’ve assumed rationality – of individuals, of businesses, etc. And with that assumption, reached a number of conclusions (which I tried to recap on Thursday) Today’s point: Like with all economics, our conclusions are only as strong as our faith in our assumptions If we want to apply these conclusions to the real world, we need to be aware of how they depend on our assumptions, and how robust they are when these assumptions are violated - 19 -