







A Pigouvian tax is a tax that is imposed to correct an externality, which arises when a person engages in behavior that harms others without their consent. Pigouvian taxes are popular among academics—with prominent economists and legal scholars arguing for their imposition on myriad goods and activities that harm third parties, like carbon emissions and alcohol. Policymakers have recently been receptive to at least some of these arguments as evidenced by taxes imposed on or proposed for a variety of externality-generating goods, including guns, plastic bags, and sugary drinks.The conventional economic rationale for Pigouvian taxes assumes that they affect behavior by increasing the prices of taxed goods and not by altering people’s underlying preferences for them. For example, a carbon tax reduces driving by making gasoline more expensive, but it otherwise leaves people’s desire to drive unchanged. This conclusion follows from the standard assumption in economics that people’s tastes and preferences are fixed and determined exogenously to public policy.Contrary to standard analysis, I argue that Pigouvian taxes can in fact shape preferences and that policymakers should consider using them for that purpose. A carbon tax, for instance, would not only make driving more expensive, it might also modify preferences such that people develop a taste for alternative modes of transportation—making driving less desirable, even if we ignore the increase in gas prices.I make an original contribution to the literature on Pigouvian taxes by explaining in detail the psychological mechanisms through which these taxes can alter preferences. I also argue that once we relax the assumption of fixed preferences, the already strong case for Pigouvian taxes often becomes even more compelling. Specifically, preference endogeneity means that the loss in consumer utility resulting from Pigouvian taxes will often be smaller than standard analysis suggests. Moreover, malleable preferences dramatically expand the potential scope for Pigouvian taxes and enhance their impact on behavior through a social multiplier effect that can make taxes more effective in achieving public policy goals than scholars have traditionally assumed. I illustrate these points in a variety of policy-relevant contexts, including environmental law, gun control, and public health policy.
Carbon Tariffs 101
We evaluate the economic and environmental consequences of taxes on imported goods based on their carbon content. The analysis uses the simplest possible partial equilibrium framework, with one small open economy and a global pollution externality. It relies on graphs of supply and demand, rather than equations or formulas, hoping to reach readers familiar with basic economics. Despite its simplicity, the framework imparts numerous lessons. (1) Absent a domestic price on carbon, a carbon tariff imposes the same costs on domestic consumers as a domestic carbon price, but a carbon tariff also subsidizes domestic pollution. (2) If one small country imposes a carbon tariff, with or without a domestic carbon tax, the economic incidence of the tariff falls on its consumers. (3) If a holdout country joins the rest of the world by enacting its own carbon regulation and consequently imports more from other countries, those increased imports are not “leakage.” They are the cessation of leakage from when the holdout country’s policy was lax. And (4) if other countries do not appropriately regulate emissions, no single small country can use a combination of carbon taxes and carbon tariffs to fully correct the problem caused by its consumers or producers.

Putting nudges in perspective
Conventional economic policy focuses on ‘economic’ solutions (e.g. taxes, incentives, regulation) to problems caused by market-level factors such as externalities, misaligned incentives and information asymmetries. By contrast, ‘nudges’ provide behavioural solutions to problems that have generally been assumed to originate from limitations in human decision making, such as present bias. While policy-makers have good reason for exploiting the power of nudges, we argue that these extremes leave open a large space of policy options that have received less attention in the academic literature. First, there is no reason that solution and problem need have the same theoretical basis: there are promising behavioural solutions to problems that have causes that are well explained by traditional economics, and conventional economic solutions often offer the best line of attack on problems of behavioural origin. Second, there is a wide range of hybrid policy actions with both economic and behavioural components (e.g. framing a tax or incentive in a specific way), and there exist many societal problems – perhaps the majority – that arise from both economic and behavioural factors (e.g. firms’ exploitation of consumers’ behavioural biases). This paper aims to remind policy-makers that behavioural economics can influence policy in a variety of ways, of which nudges are the most prominent but not necessarily the most powerful.

The i-frame and the s-frame: How focusing on individual-level solutions has led behavioral public policy astray
An influential line of thinking in behavioral science, to which the two authors have long subscribed, is that many of society's most pressing problems can be addressed cheaply and effectively at the level of the individual, without modifying the system in which the individual operates. We now believe this was a mistake, along with, we suspect, many colleagues in both the academic and policy communities. Results from such interventions have been disappointingly modest. But more importantly, they have guided many (though by no means all) behavioral scientists to frame policy problems in individual, not systemic, terms: To adopt what we call the “i-frame,” rather than the “s-frame.” The difference may be more consequential than i-frame advocates have realized, by deflecting attention and support away from s-frame policies. Indeed, highlighting the i-frame is a long-established objective of corporate opponents of concerted systemic action such as regulation and taxation. We illustrate our argument briefly for six policy problems, and in depth with the examples of climate change, obesity, retirement savings, and pollution from plastic waste. We argue that the most important way in which behavioral scientists can contribute to public policy is by employing their skills to develop and implement value-creating system-level change.

Yeah, We're Going to Have to Tax the Middle Class
Fungibility and Consumer Choice: Evidence from Commodity Price Shocks*
Abstract We formulate a test of the fungibility of money based on parallel shifts in the prices of different quality grades of a commodity. We embed the test in a discrete-choice model of product quality choice and estimate the model using panel microdata on gasoline purchases. We find that when gasoline prices rise, consumers substitute to lower octane gasoline, to an extent that cannot be explained by income effects. Across a wide range of specifications, we consistently reject the null hypothesis that households treat “gas money” as fungible with other income. We compare the empirical fit of three psychological models of decision making. A simple model of category budgeting fits the data well, with models of loss aversion and salience both capturing important features of the time series.

Behavioural economics, consumer behaviour and consumer policy: state of the art
Counter to the traditional assumption of neoclassical economics that individuals are rational Homo oeconomici that always seek to maximize their utility and follow their ‘true’ preferences, research in behavioural economics has demonstrated that people's judgements and decisions are often subject to systematic biases and heuristics, and are strongly dependent on the context of the decision. In this article, we briefly review the transition of research from neoclassical economics to behavioural economics, and discuss how the latter has influenced research in consumer behaviour and consumer policy. In particular, we discuss the impacts of key principles such as status quo bias, the endowment effect, mental accounting and the sunk-cost effect, other heuristics and biases related to availability, salience, the anchoring effect and simplicity rules, as well as the effects of other supposedly irrelevant factors such as music, temperature and physical markers on consumers’ decisions. These principles not only add significantly to research on consumer behaviour – they also offer readily available practical implications for consumer policy to nudge behaviour in beneficial directions in consumption domains including financial decision making, product choice, healthy eating and sustainable consumption.

Characterizing the causes, dynamics, and consequences of choice deferral
The fact that people often avoid making decisions is well known, and past research has helped to identify some of the conditions and reasons for doing so. For instance, people may forgo choices between bad options because they prefer not to end up with one of those options. It is much less clear when and why people avoid choosing in cases where they eventually will have to make a given decision. To study such instances of choice deferral, we presented participants with a series of choices, and for each choice they were allowed to either choose immediately or defer the decision until later in the experiment. Across six experiments and three choice domains (choices among consumer goods, artwork, and political candidates), we find that the strongest predictor of choice deferral is the overall value of a given set of options, with relative value (i.e., how hard it is to identify the best option) counterintuitively playing a smaller role. We show that the influence of overall value on choice deferral can be accounted for by a dynamic decision model according to which participants appraise the option set relative to a criterion before deciding whether to choose or defer, comparing this to a previous model whereby participants make such a decision based on a predetermined decision time limit. We further reveal that the influence of overall value on choice deferral is determined by how congruent options are with a given choice goal (choose-best or choose-worst) rather than simply how bad those options are. Collectively, our findings shed new light on how people decide to put off the inevitable.
Restoring Consumer Sovereignty
For decades, there has been broad consensus within antitrust, intellectual property, and consumer law scholarship that consumers make decisions in their own best interests by consciously weighting the market’s relative prices, quantities, and qualities against each other. That consensus is unraveling in light of novel findings from cognitive and social psychology that explain how individuals’ concepts of what they prefer drive the global economy. At the same time, producers nowadays no longer merely satisfy consumers’ needs but also communicate their values, identities, and aspirations through the sale and marketing of products. As part of the growing interest in observations such as these, a wealth of psychological studies challenge the fundamental teaching of economics that the interplay of demand and supply of goods in a free market economy provides us with material wealth. This book provides a normative defense of that assumption and a theoretical framework for understanding its contradictions. It argues that the erosion of consumer sovereignty through the ability of product manufacturers and sellers to systematically take advantage of individuals’ psychological weaknesses demands a twenty-first-century reconceptualization of the consumer and a modern account of how the law should regulate the digital economy. Such an account is justified to ensure a diverse marketplace in which consumers can influence how our societies are structured and arranged. By examining the role that market manipulation plays, it offers ingredients for a realistic descriptive and normative market regulatory theory that is aware of its political economy, its behavioral suppositions, and its distributional consequences.

The Red and the Black: Mental Accounting of Savings and Debt
In the standard economic account of consumer behavior the cost of a purchase takes the form of a reduction in future utility when expenditures that otherwise could have been made are forgone. The reality of consumer hedonics is different. When people make purchases, they often experience an immediate pain of paying, which can undermine the pleasure derived from consumption. The ticking of the taxi meter, for example, reduces one's pleasure from the ride. We propose a “double-entry” mental accounting theory that describes the nature of these reciprocal interactions between the pleasure of consumption and the pain of paying and draws out their implications for consumer behavior and hedonics. A central assumption of the model, which we call prospective accounting, is that consumption that has already been paid for can be enjoyed as if it were free and that the pain associated with payments made prior to consumption (but not after) is buffered by thoughts of the benefits that the payments will finance. Another important concept is coupling, which refers to the degree to which consumption calls to mind thoughts of payment, and vice versa. Some financing methods, such as credit cards, tend to weaken coupling, whereas others, such as cash payment, produce tight coupling. Our model makes a variety of predictions that are at variance with economic formulations. Contrary to the standard prediction that people will finance purchases to minimize the present value of payments, our model predicts strong debt aversion—that they should prefer to prepay for consumption or to get paid for work after it is performed. Such pay-before sequences confer hedonic benefits because consumption can be enjoyed without thinking about the need to pay for it in the future. Likewise, when paying beforehand, the pain of paying is mitigated by thoughts of future consumption benefits. Contrary to the economic prediction that consumers should prefer to pay, at the margin, for what they consume, our model predicts that consumers will find it less painful to pay for, and hence will prefer, flat-rate pricing schemes such as unlimited Internet access at a fixed monthly price, even if it involves paying more for the same usage. Other predictions concern spending patterns with cash, charge, or credit cards, and preferences for the earmarking of purchases. We test these predictions in a series of surveys and in a conjoint-like analysis that pitted our double-entry mental accounting model against a standard discounting formulation and another benchmark that did not incorporate hedonic interactions between consumption and payments. Our model provides a better fit of the data for 60% of the subjects; the discounting formulation provides a better fit for only 29% of the subjects (even when allowing for positive and negative discount rates). The pain of paying, we argue, plays an important role in consumer self-regulation, but is hedonically costly. From a hedonic perspective the ideal situation is one in which payments are tightly coupled to consumption (so that paying evokes thoughts about the benefits being financed) but consumption is decoupled from payments (so that consumption does not evoke thoughts about payment). From an efficiency perspective, however, it is important for consumers to be aware of what they are paying for consumption. This creates a tension between hedonic efficiency and what we call decision efficiency. Various institutional arrangements, such as financing of public parks through taxes or usage fees, play into this tradeoff. A producer developing a pricing structure for their product or service should be aware of these two conflicting objectives, and should try to devise a structure that reconciles them.

Will Canada’s gas tax holiday drive up emissions and help the rich? | The Narwhal
The Carney government is keeping its tax off at gas pumps to help with the cost of living, but critics call it a subsidy for the oil and gas industry that won’t help those who need it most

Opinion | One Senator’s Plea for Tariff Breaks
How protectionism works in practice: Public support, but seeking exemptions in private.
Extractive taxation and the French Revolution
Extractive taxation is considered one of the main causes of the French Revolution. This column exploits regional variations in the French salt tax, which accounted for 22% of royal revenues in 1780, to document that areas of France burdened by a higher tax rate experienced more revolts in the years leading up to the Revolution. These effects were amplified by droughts that increased food prices and activated latent discontent. It suggests that when taxation is imposed without representation, it can become a catalyst for popular unrest, especially after negative economic shocks.

Choice Bracketing
When making many choices, a person can broadly bracket them by assessing the consequences of all of them taken together, or narrowly bracket them by making each choice in isolation. We integrate research conducted in a wide range of decision contexts which shows that choice bracketing is an important determinant of behavior. Because broad bracketing allows people to take into account all the consequences of their actions, it generally leads to choices that yield higher utility. The evidence that we review, however, shows that people often fail to bracket broadly when it would be feasible for them to do so. In addition to documenting the diverse effects of bracketing, we also discuss factors that determine whether people bracket narrowly or broadly. We conclude with a discussion of normative aspects of bracketing and argue that there are some situations in which narrower bracketing results in superior decision making.

Integrative experiments identify how punishment affects welfare in public goods games
Despite decades of research, the conditions under which punishment promotes cooperation remain unclear. Through an integrative experiment varying 14 design parameters of public goods games across 360 experimental conditions (147,618 decisions from 7100 participants), we reveal substantial heterogeneity in punishment effectiveness: Its impact on welfare ranges from 43% improvement to 44% reduction depending on the game parameters. To characterize these patterns, we developed models that outperformed human forecasters in predicting punishment effectiveness in new experiments. Communication emerges as the most important factor, followed by contribution framing (opt out versus opt in), contribution type (variable versus all-or-nothing), game length, and outcome visibility, though these factors often interact. The results reframe the debate from whether punishment works to when it does, demonstrating how integrative experiments enable discovery of generalizable patterns in social phenomena. , Editor’s summary People face conflicts between maximizing personal gain versus supporting collective interests. If we cooperatively recycle or donate to charities, it benefits society, but it also costs us time and resources that could be selfishly preserved for ourselves. We impose penalties to deter those undesirable or selfish behaviors, but under what conditions do punishments or penalties effectively modify behavior to benefit group welfare? Alsobay et al . systematically and simultaneously varied 14 factors together instead of in isolation. Punishment was unequivocally most effective when paired with consistent communication, particularly over time. Another effective factor was “opting out” or withdrawing some, but not all, endowments already in the public fund. These methodological advances revealed when, rather than whether, punishment works. —Ekeoma Uzogara , INTRODUCTION Human societies face many situations where individual and collective interests conflict, often referred to as social dilemmas. Costly peer punishment has been studied for more than 25 years in public goods games (stylized behavioral experiments in which individuals decide how much to contribute to a shared pool that benefits everyone) as a mechanism to promote cooperation. Prior research has identified many contextual factors that moderate punishment’s effectiveness, including game length, communication, group size, punishment cost, and so on. However, the specific conditions under which punishment improves group welfare remain unclear. RATIONALE We argue that this lack of clarity derives from the dominant experimental paradigm, in which any given study manipulates only one or a few theoretically informed factors. Because such studies differ in many ways (different experimental procedures, populations), their results are often difficult to compare or integrate. Consequently, one can list many factors that have some effect, but cannot say how much each matters relative to the others, or how they work together, and as a result, cannot predict when punishment will help or harm welfare in new settings. To address this fundamental knowledge gap, we use an integrative experimental design and systematically vary 14 parameters across 360 conditions (147,618 decisions from 7100 participants) to elucidate when punishment improves versus undermines welfare in public goods games, which factors matter most, and how they interact. RESULTS The effect of punishment on welfare ranged from 43% improvement to 44% reduction depending on the specific combination of game parameters. To characterize this heterogeneity, we trained a model that outperformed all 553 human forecasters (laypeople and experts) in predicting whether punishment would help or harm welfare in new experiments. Communication emerged as roughly three times more important than any other factor, followed by contribution framing (opt in versus opt out), contribution type (variable versus all-or-nothing), game length, and peer outcome visibility (whether participants can see others’ earnings). These factors often interact. For example, longer games enhance punishment’s effectiveness only when communication is available, and contribution framing effects depend on both contribution type and outcome visibility. CONCLUSION Many phenomena in social science are shaped by many factors whose interactions are consequential, yet the dominant experimental paradigm often limits its inquiry to “does a given effect exist?” and examines hypothesized factors in isolation. As a result, research programs can accumulate many partial explanations without a clear picture of how they combine to determine outcomes across settings. Knowing that factors matter individually is fundamentally different from knowing how much each matters and how they interact. The integrative approach implemented here offers one way forward. It varies many factors simultaneously within a shared design space, evaluates models by their predictive accuracy on new experiments, and probes those models to constrain and develop theory. Our hope is that integrative experiment designs, combined with models that integrate prediction and explanation, represent a path toward more cumulative social science. Integrative experiment reveals when punishment helps versus harms. We systematically varied 14 design parameters across 360 experimental conditions. The effect of punishment on cooperation efficiency ranged from −44% to +43% depending on the specific game parameters. Communication emerged as three times more important than any other factor, followed by contribution framing, contribution type, and game length.

Social Norms
Social norms, the informal rules that govern behavior in groups andsocieties, have been extensively studied in the social sciences.Anthropologists have described how social norms function in differentcultures (Geertz 1973), sociologists have focused on their socialfunctions and how they motivate people to act (Durkheim 1895 [1982],1950 [1957]; Parsons 1937; Parsons & Shils 1951; James Coleman1990; Hechter & Opp 2001), and economists have explored howadherence to norms influences market behavior (Akerlof 1976; Young1998a). More recently, also legal scholars have touted social norms asefficient alternatives to legal rules, as they may internalizenegative externalities and provide signaling mechanisms at little orno cost (Ellickson 1991; Posner 2000).
