Virtually all current theories of choice under risk or uncertainty are cognitive and consequentialist. They assume that people assess the desirability and likelihood of possible outcomes of choice alternatives and integrate this information through some type of expectation-based calculus to arrive at a decision. The authors propose an alternative theoretical perspective, the risk-as-feelings hypothesis, that highlights the role of affect experienced at the moment of decision making. Drawing on research from clinical, physiological, and other subfields of psychology, they show that emotional reactions to risky situations often diverge from cognitive assessments of those risks. When such divergence occurs, emotional reactions often drive behavior. The risk-as-feelings hypothesis is shown to explain a wide range of phenomena that have resisted interpretation in cognitive-consequentialist terms.

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Among the most popular models for decision under risk and uncertainty are the rank-dependent models, introduced by Quiggin and Schmeidler. Central concepts in these models are rank-dependence and comonotonicity. It has been suggested in the literature that these concepts are technical tools that have no intuitive or empirical content. This paper describes such contents. As

The 30th anniversary of The Journal of Portfolio Management is a milestone in the rich intellectual history of modern finance, firmly establishing the relevance of quantitative models and scientific inquiry in the practice of financial management. One of the most enduring ideas from this intellectual history is the Efficient Markets Hypothesis (EMH), a deceptively simple notion that has become a lightning rod for its disciples and the proponents of behavioral economics and finance. In its purest form, the EMH obviates active portfolio management, calling into question the very motivation for portfolio research. It is only fitting that we revisit this groundbreaking idea after three very successful decades of this Journal. In this article, I review the current state of the controversy surrounding the EMH and propose a new perspective that reconciles the two opposing schools of thought. The proposed reconciliation, which I call the Adaptive Markets Hypothesis (AMH), is based on an evolutionary approach to economic interactions, as well as some recent research in the cognitive neurosciences that has been transforming and revitalizing the intersection of psychology and economics. Although some of these ideas have not yet been fully articulated within a rigorous quantitative framework, long time students of the EMH and seasoned practitioners will no doubt recognize immediately the possibilities generated by this new perspective. Only time will tell whether its potential will be fulfilled. I begin with a brief review of the classic version of the EMH, and then summarize the most significant criticisms leveled against it by psychologists and behavioral economists. I argue that the sources of this controversy can

This paper develops a new method of estimating risk aversion using data on labor supply behavior. In particular, I show that existing evidence on labor supply behavior places a tight upper bound on risk aversion in the expected utility model. I derive a formula for the coefficient of relative risk aversion ( ) in terms of (1) the ratio of the income elasticity of labor supply to the wage elasticity and (2) the degree of complementarity between consumption and labor. I bound the degree of complementarity using data on consumption choices when labor supply varies randomly across states. Using labor supply elasticity estimates from thirty-three studies, I find a mean estimate of 1: I then show that generating> 2 would require that wage increases cause sharper reductions in labor supply than estimated in any of the studies.

Five descriptive models of risky decision making are tested in this article, including four quantitative models and one heuristic account. Seven studies with 1802 participants were conducted to compare accuracy of predictions to new tests of first order stochastic dominance. Although the heuristic model was a contender in previous studies, it can be rejected by the present data, which show that incidence of violations varies systematically with the probability distribution in the gambles. The majority continues to violate stochastic dominance even when two of three branches have higher consequences in the dominant gamble, and they persist in mixed gambles even when probability to win is higher and probability to lose is lower in the dominant gamble. The transfer of attention exchange model (TAX) was the most accurate model for predicting the results.

The economic conception of human behavior assumes that a person has a single set of well-defined goals, and that the person’s behavior is chosen to best achieve those goals. We develop a model in which a person’s behavior is the outcome of an interaction between two systems: a deliberative system that assesses options with a broad, goal-based perspective, and an affective system that encompasses emotions and motivational drives. Our model provides a framework for understanding many departures from full rationality discussed in the behavioral-economics literature, and captures the familiar feeling of being “of two minds. ” And by focusing on factors that moderate the relative influence of the two systems, our model also generates a variety of novel testable predictions.

Expected utility theory, prospect theory, and most other models of risky choice are based on the fundamental premise that individuals choose among risky prospects by balancing the value of the possible consequences. These models, therefore, require that the value of a risky prospect lie between the value of that prospect’s highest and lowest outcome. Although this requirement seems essential for any theory of risky decision-making, we document a violation of this condition in which individuals value a risky prospect less than its worst possible realization. This demonstration, which we term the uncertainty effect, draws from more than 1000 experimental participants, and includes hypothetical and real pricing and choice tasks, as well as field experiments in real markets with financial incentives. Our results suggest that there are choice situations in which decision-makers discount lotteries for uncertainty in a manner that cannot be accommodated by standard models of risky choice. From the time of Bernoulli on, it has been common to argue that (a) individuals tend to display aversion to the taking of risks, and (b) that risk aversion in turn is an explanation for many observed phenomena in the economic world [Arrow 1971, p. 90]. I.

violate prospect theory. They suggest that prospect theory’s hypothesis of an S-shaped value function, concave for gains and convex for losses, is incorrect. However, all the data of Levy and Levy are perfectly consistent with the predictions of prospect theory, as can be verified by simply applying prospect theory formulas. The mistake of Levy and Levy is that they, incorrectly, thought that probability weighting could be ignored.

People exaggerate the degree to which their future tastes will resemble their current tastes. We present evidence from a variety of domains which demonstrates the prevalence of such projection bias, develop a formal model of it, and use this model to demonstrate its importance in economic environments. Projection bias leads people to overvalue reference-dependent goods and magnifies the endowment e¤ect. It can cause misguided purchases of durable goods. When there is habit formation, projection bias can lead people to consume too much early in life, and to decide, as time passes, to consume more — and save less — than originally planned.