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Protocol analysis, in the form of concurrent verbal ‘thinking aloud’ reports, is a method of collecting and analyzing data about cognitive processes. This approach can help economists in evaluating competing theories of behavior and in categorizing heterogeneity of thinking patterns. As a proof of concept, I tested this method in the context of a guessing game. I found that concurrent think aloud protocols can inform us about individual’s thought processes without affecting decisions. The method allowed me to identify game theoretic thinking and heterogeneous approaches to unravelling the guessing game. The think aloud protocol is inexpensive and scalable, and it is a useful tool for identifying empirical regularities regarding decision processes.

We present data from an incentivized online experiment and responses from a set of validated psychological questionnaires to measure entrepreneurs' risk and time preferences and to identify entrepreneurs' personality characteristics. The analyses of the data suggest that intrinsic motivation positively relates to the likelihood of owning a business (i.e., being an active entrepreneur). We also found that subjects who scored higher on drive were relatively more risk seeking while those who scored higher on pessimism were more patient. The results of our study highlight the importance of studying personality traits to better understand what drives people to own a business.

The way we describe and evaluate ourselves or self-concept has a significant effect on our behaviors. An individual who describes herself as altruistic is more likely to engage in helpful behaviors than someone who does not possess such self-concept. Self-concept, in turn, is influenced by personality. In this paper, we propose that self-concept mediates the effects of personality on volunteering. We tested this idea experimentally with Amazon Mechanical Turk workers. In our experiment, participants answered a series of questionnaires, including the Big Five personality test and attitudinal questions that we used to construct an index representing altruistic self-concept. Participants were also given the option to make and keep a promise to volunteer by donating time and effort to a charity. Our results show that agreeableness has a strong influence on volunteering through its effect on altruistic self-concept.

We study experimentally the effect of personality traits on the willingness to make and keep a promise to volunteer. In our experiment, Amazon Mechanical Turk participants were given the option to volunteer by donating time and effort to a charity. They also answered a series of questionnaires, including the Big Five personality test and attitudinal questions that we used to construct an index representing altruistic self-concept. Self-concept refers to the way we describe and evaluate ourselves. We find that altruistic self-concept mediates how personality affects volunteering decisions. In particular, agreeableness has a strong influence on the probability of making and keeping promises to volunteer through its effect on altruistic self-concept. Our findings have useful implications for non-profit organizations.

We study the effect of time flexibility on volunteering. Using an online experiment, we tested predictions of a model of inter-temporal volunteering. Consistent with our theoretical predictions, we find that flexibility in choosing when to allocate effort donations increases overall donations despite the added incentive to renege on a promise to donate. Furthermore, compared to monetary donations, donation rates are higher when people donate effort. We provide a framework for understanding these results.

a b s t r a c t This paper tests whether strategic uncertainty employs circuits in the brain that encode risk and utility, or circuits that are involved in Theory of Mind (ToM). We compare participants' decisions in a stag-hunt game with an equivalent choice between Bernoulli lotteries where the probabilities are equal to the mixed Nash equilibrium of the stag hunt game. Behavioral data suggests that most participants are more willing to choose the payoff-dominant option in a stag-hunt game than the equivalent lottery. Neuroimaging shows that activations in the regions of the brain commonly associated with ToM are correlated with a participant's propensity to choose payoff dominant. This suggests that individuals who mentalize the other person are more likely to be cooperative than those who do not.

We investigated behavioral and neurobiological mechanisms by which risk-averse advice, provided by an expert, affected risky decisions across three developmental groups [early adolescents (12–14 years), late adolescents (15–17 years), adults (18+ years)]. Using cumulative prospect theory, we modeled choice behavior during a risky-choice task. Results indicate that advice had a significantly greater impact on risky choice in both adolescent groups than in adults. Using functional magnetic resonance imaging, we investigated the neural correlates of this behavioral effect. Developmental effects on correlations between brain activity and valuation parameters were obtained in regions that can be classified into (i) cognitive control regions, such as dorsolateral prefrontal cortex (DLPFC) and ventrolateral PFC; (ii) social cognition regions, such as posterior temporoparietal junction; and (iii) reward-related regions, such as ventromedial PFC (vmPFC) and ventral striatum. Within these regions, differential effects of advice on neural correlates of valuation were observed across development. Specifically, advice increased the correlation strength between brain activity and parameters reflective of safe choice options in adolescent DLPFC and decreased correlation strength between activity and parameters reflective of risky choice options in adult vmPFC. Taken together, results indicate that, across development, distinct brain systems involved in cognitive control and valuation mediate the risk-reducing effect of advice during decision making under risk via specific enhancements and reductions of the correlation strength between brain activity and valuation parameters.

We investigate the effects of mood on decisions in random nth-price auctions. There are two possible ways in which mood can affect behavior: (1) mood can affect the valuation of the object being auctioned or the willingness to pay (WTP), and (2) mood can affect the bidding behavior itself. To identify these two possible effects, we study decisions with induced values and with homegrown values. Our data show that positive mood generates an upward bidding bias in the induced value condition. However, only under certain conditions do we observe weak mood effects on WTP.

The majority of decision-related research has focused on how the brain computes decisions over outcomes that are positive in expectation. However, much less is known about how the brain integrates information when all possible outcomes in a decision are negative. To study decision-making over negative outcomes, we used fMRI along with a task in which participants had to accept or reject 50/50 lotteries that could result in more or fewer electric shocks compared to a reference amount. We hypothesized that behaviorally, participants would treat fewer shocks from the reference amount as a gain, and more shocks from the reference amount as a loss. Furthermore, we hypothesized that this would be reflected by a greater BOLD response to the prospect of fewer shocks in regions typically associated with gain, including the ventral striatum and orbitofrontal cortex (OFC). The behavioral data suggest that participants in our study viewed all outcomes as losses, despite our attempt to induce a status quo. We find that the ventral striatum showed an increase in BOLD response to better potential gambles (i.e. fewer expected shocks). This lends evidence to the idea that the ventral striatum is not solely responsible for reward processing but that it might also signal the relative value of an expected outcome or action, regardless of whether the outcome is entirely appetitive or aversive. We also find a greater response to worse gambles in regions previously associated with aversive valuation, suggesting an opposing but simultaneous valuation signal to that conveyed by the striatum.

We report results of one-shot traveler’s dilemma game experiments to test the predictions of a model of introspection. The model describes a noisy out-of-equilibrium process by which players reach a decision of what to do in one-shot games. To test the robustness of the model and to compare it to other models of introspection without noise, we introduce non-binding advice. Advice has the effect of coordinating all players’ beliefs onto a common strategy. Experimentally, advice is implemented by asking subjects who participated in a repeated traveler’s dilemma game to recommend an action to subjects playing one-shot games with identical parameters. In contrast to observations, models based on best-response dynamics would predict lower claims than the advised. We show that our model’s predictions with and without advice are consistent with the data.

We describe a common pool resource game in which players choose how much of the stock to extract in a sequential manner. There are two choices and one represents taking a larger proportion of the stock than the other. After a player makes a choice, the remaining stock grows at a constant rate. We consider a game with a finite number of alternating moves. It is shown that changes in the larger proportion of the stock that the players are allowed to take and the growth rate affect equilibrium, but have little effect on behavior in the laboratory. In addition to observing more cooperation than predicted, we observe that parameters that are strategically irrelevant affect behavior. The results of this research might help policy makers in developing adequate policies to prevent overexploitation of some natural renewable resources.

This paper considers a duopoly price-choice game in which the unique Nash equilibrium is the Bertrand outcome. Price competition, however, is imperfect in the sense that the market share of the high-price firm is not zero. Economic intuition suggests that price levels should be positively related to the market share of the high-price firm. Although this relationship is not predicted by standard game theory, it is implied by a generalization of the Nash equilibrium that results when players make noisy (logit) best responses to expected payoff differences. This logit equilibrium model was used to design a laboratory experiment with treatments that correspond to changing the market share of the high-price firm. The model predicts the final-period price averages for both treatments with remarkable accuracy. Moreover computer simulations of a naive learning model were used, ex ante, to predict the observed differences in the time paths of average prices.

Classroom market experiments can complement the theoretical orientation of standard industrial organization courses. This paper describes various experiments designed for such courses, and presents details of a multi-market game with entry and exit. In this experiment incumbents have a cost advantage in their ‘home’ markets, and mobile firms decide which market to enter. After entry decisions are made, firms choose prices and quantities to offer for sale. Predatory pricing is possible with this setup, and the experiment can be used to motivate discussions of monopoly, competition, entry, and efficiency. Other classroom experiments with an industrial organization focus are surveyed.

The notion of a Nash equilibrium has joined supply and demand as one of the two or three techniques that economists instinctively try to use first in the analysis of economic interactions. Moreover, the Nash equilibrium and closely related game-theoretic concepts are being widely applied in other social sciences and even in biology, where evolutionary stability often selects a subset of the Nash equilibria. Many people are uneasy about the stark predictions of the Nash equilibrium in some contexts where the extreme rationality assumptions seem implausible. Kaushik Basu’s (1994) “traveler’s dilemma” is a particularly convincing example of a case where the unrelenting logic of game theory is at odds with intuitive notions about human behavior. The story associated with the dilemma is that two travelers purchase identical antiques while on a tropical vacation. Their luggage is lost on the return trip, and the airline asks them to make independent claims for compensation. In anticipation of excessive claims, the airline representative announces

The current credit rationing heavily influences entrepreneurship and, more dramatically, the viability of innovation projects. In this context, mechanisms to screen successful projects are of paramount importance for both lenders and entrepreneurs. We present an experiment to test the collateral-interest mechanism of credit screening. Our results confirm that incentive-compatible pairs of collateral-interest rate can distinguish between projects of different success probability, even in moral hazard settings.

There are two regularities we have learned from experimental studies of choice under risk. The first is that the majority of people weigh objective probabilities non-linearly. The second regularity, although less commonly acknowledged, is that there is a large amount of heterogeneity in how people distort probabilities. Despite of this, little effort has been made to identify the source of heterogeneity. In this paper, we explore the possibility that the probability distortions are linked to the personality profile of the decision maker. Using four widely utilized personality tests, we classify participants into three distinct personality types and find that these types have different risk characteristics. Particularly, the trait of motivation plays a role in explaining the attraction of gambling, while the trait of impulsiveness affects the discriminability of non-extreme probabilities. Our results suggest heterogeneity in probability distortions may be explained by personality profiles, which can be elicited though standard questionnaires.

There are two regularities we have learned from experimental studies of choice under risk. The first is that the majority of people weigh objective probabilities non-linearly. The second regularity, although less commonly acknowledged, is that there is a large amount of heterogeneity in how people distort probabilities. Despite this, little effort has been made to identify the source of heterogeneity. In this paper, we explore the possibility that the probability distortions are linked to the personality profile of the decision-maker. Using four widely utilized personality tests, we classify participants into three distinct personality types and find that these types have different risk characteristics. Particularly, the trait of motivation plays a role in explaining the attraction of gambling, while the trait of impulsiveness affects the discriminability of non-extreme probabilities. Our results suggest heterogeneity in probability distortions may be explained by personality profiles, which can be elicited though standard questionnaires.

Entrepreneurs are often thought to be risk-taking and patient individuals who, unlike non-entrepreneurs, are willing to forgo their existing resources for a chance of a future larger reward. Entrepreneurs are also thought to more motivated, reward driven, and overconfident than others. How reliable are these assumptions? To establish a correlation between individual characteristics and entrepreneurship, we developed an incentivized online experiment that consisted of three risk decision tasks, a time decision task, and a set of validated psychological questionnaires. We elicited individual risk attitudes and time preferences and found that our sampled entrepreneurs and non-entrepreneurs did not exhibit statistically significant differences in risk and time preferences. We also found that psychological personality traits correlated with both risk attitudes and patience: individuals who scored higher on drive were more risk seeking, and individuals who had higher IQ and those who scored higher on pessimism were more patient; in addition, intrinsic motivation was positively related to the likelihood of being an entrepreneur. Our results suggest that individual personality profiles can play an important role in explaining economic preferences and entrepreneurship.

The disposition effect is a phenomenon in which investors hold onto losing assets longer than they hold onto gaining assets. In this study, we used functional magnetic resonance imaging (fMRI) to measure the response of valuation regions in the brain during the decision to keep or to sell an asset that followed a random walk in price. The most common explanation for the disposition effect is preference-based: namely, that people are risk-averse over gains and risk-seeking over losses. This explanation would predict correlations between individuals' risk-preferences, the magnitude of their disposition effect, and activation in valuation structures of the brain. We did not observe these correlations. Nor did we find evidence for a realization utility explanation, which would predict differential responses in valuation regions during the decision to sell versus keep an asset that correlated with the magnitude of the disposition effect. Instead, we found an attenuated ventral striatum response to upticks in value below the purchase price in some individuals with a large disposition effect. Given the role of the striatum in signaling prediction error, the blunted striatal response is consistent with the expectation that an asset will rise when it is below the purchase price, thus spurring loss-holding behavior. This suggests that for some individuals, the disposition effect is likely driven by a belief that the asset will eventually return to the purchase price, also known as mean reversion.

Sacred values, such as those associated with religious or ethnic identity, underlie many important individual and group decisions in life, and individuals typically resist attempts to trade off their sacred values in exchange for material benefits. Deontological theory suggests that sacred values are processed based on rights and wrongs irrespective of outcomes, while utilitarian theory suggests that they are processed based on costs and benefits of potential outcomes, but which mode of processing an individual naturally uses is unknown. The study of decisions over sacred values is difficult because outcomes cannot typically be realized in a laboratory, and hence little is known about the neural representation and processing of sacred values. We used an experimental paradigm that used integrity as a proxy for sacredness and which paid real money to induce individuals to sell their personal values. Using functional magnetic resonance imaging (fMRI), we found that values that people refused to sell (sacred values) were associated with increased activity in the left temporoparietal junction and ventrolateral prefrontal cortex, regions previously associated with semantic rule retrieval. This suggests that sacred values affect behaviour through the retrieval and processing of deontic rules and not through a utilitarian evaluation of costs and benefits.

Economics has always prided itself on having a unifying theoretical framework based on rational choice theory. However, data from controlled experiments, which often provide theory the best chance to work, refute many of the rationality assumptions that economists make. The evidence against rational choice, as traditionally defined, has forced economists to rethink their traditional models. However, despite the investment of many brilliant minds in the pursuit of better behavioral models of choice, behavioral economics has so far made little progress in providing an alternative paradigm that would be both parsimonious and accurate. In this chapter, we review the evidence against rational choice and the ways in which behavioral economists have responded. In addition, we put forward the idea that evolutionary psychology can give economics back its overriding paradigm. Evolutionary psychology can place structure on the utility function and provide content to rationality. By doing so, it can explain many of the behavioral anomalies that behavioral economists and psychologists have documented. If economists are willing to use the evolutionary psychology paradigm, then they can regain theoretical consistency of their discipline and have models that are better descriptors and predictors of behavior.

Background: Myelination of white matter in the brain continues throughout adolescence and early adulthood. This cortical immaturity has been suggested as a potential cause of dangerous and impulsive behaviors in adolescence. Methodology/Principal Findings: We tested this hypothesis in a group of healthy adolescents, age 12–18 (N = 91), who underwent diffusion tensor imaging (DTI) to delineate cortical white matter tracts. As a measure of real-world risk taking, participants completed the Adolescent Risk Questionnaire (ARQ) which measures engagement in dangerous activities. After adjusting for age-related changes in both DTI and ARQ, engagement in dangerous behaviors was found to be positively correlated with fractional anisotropy and negatively correlated with transverse diffusivity in frontal white matter tracts, indicative of increased myelination and/or density of fibers (ages 14–18, N = 60). Conclusions/Significance: The direction of correlation suggests that rather than having immature cortices, adolescents who engage in dangerous activities have frontal white matter tracts that are more adult in form than their more conservative peers.

We introduce an experimental approach to study the effect of institutions on economic growth. In each period, agents produce and trade output in a market, and allocate it to consumption and investment. Productivity is higher if total capital stock is above a threshold. The threshold externality generates two steady states – a suboptimal poverty trap and an optimal steady state. In a baseline treatment, the economies converge to the poverty trap. However, the ability to make public announcements or to vote on competing and binding policies, increases output, welfare and capital stock. Combining these two simple institutions guarantees that the economies escape the poverty trap.

Purpose – We summarize three previous neuroeconomic studies with two features that distinguish them from most others in experimental economics: (1) the use of physical pain to induce incentives and (2) acquisition of data on brain activation levels. By correlating behavior when payoffs are painful with brain activation, we are able to test for the neurobiological relevance of important phenomena previously observed in experimental studies that are at odds with classical economic theories of decision-making. These specific phenomena are (a) negative discounting of future payoffs; (b) nonlinear probability weighting; (c) the experience of regret and rejoice when making a decision under risk. Methodology/approach – The expectation of pain is created through the use of mild electric shocks to the top of the foot. Pain confers disutility, so decisions are made in the domain of losses relative to the status quo. Simultaneous with these decisions, brain activation data is acquired through functional magnetic resonance imaging (fMRI). Findings – We find evidence for negative time discounting of electric shocks. Participants who exhibited the most extreme forms of this discounting were distinguished by early and robust activation of a subset of the cortical pain matrix. We also find evidence for probability weighting in the domain of electric shocks, which is manifest at the neural level. We find evidence both behaviorally and neurally for regret and rejoice functions for painful outcomes. Originality/value of chapter – Previous experimental economic studies in the domain of losses have typically used monetary rewards. Here, we report behavioral effects and neural correlates using pain.

While mainstream economic models assume that individuals treat probabilities objectively, many people tend to overestimate the likelihood of improbable events and underestimate the likelihood of probable events. However, a biological account for why probabilities would be treated this way does not yet exist. While undergoing fMRI, we presented individuals with a series of lotteries, defined by the voltage of an impending cutaneous electric shock and the probability with which the shock would be received. During the prospect phase, neural activity that tracked the probability of the expected outcome was observed in a circumscribed network of brain regions that included the anterior cingulate, visual, parietal, and temporal cortices. Most of these regions displayed responses to probabilities consistent with nonlinear probability weighting. The neural responses to passive lotteries predicted 79% of subsequent decisions when individuals were offered choices between different lotteries, and exceeded that predicted by behavior alone near the indifference point.

In this paper we study whether mood affects: 1) Willingness to pay (WTP); and 2) The effectiveness of the demand revealing mechanism. We study decisions using a random nth price auction with induced values and homegrown values. Our data show no clear support for negative mood effects on WTP and, under some conditions, they show weak support for positive mood effects on WTP. However, mood does affect the effectiveness of the value elicitation mechanism in revealing value. Under a good mood, subjects submit bids that are significantly higher than their induced values.

Nonbinding communication, or cheap talk, has been associated with the resolution of coordination failures and social dilemmas in both laboratory and field experiments (see Cooper, et al., 1992, and Clark, Kay, and Sefton, 2000; Isaac and Walker, 1991; Ostrom and Walker, 1991; Ostrom, Gardner and Walker, 1994; and Cardenas, Ahn, and Ostrom, 2003). In simple coordination games, communication is expected to reduce the uncertainty of what other players are likely to do and hence facilitate coordination in the better equilibrium. In social dilemma games, the reasons why communication works are still unclear. Perhaps communication results in an increased sense of group identity, an enhancement of normative orientations toward cooperation, or a necessity to avoid (seek) verbal reprimand (approval) when promises of cooperation are violated (fulfilled). In this paper we use a simple neoclassical growth model with multiple equilibria to investigate the mechanism by which non-binding communication results in lower equilibrium resource extraction. We use a growth model because it provides an adequate dynamic framework for modeling extraction of a natural resource with threshold externalities.

Psychologists have established that task complexity, gender, and group identity affect conformity rates. We test the effects of these variables in contribution games. Our experiments consist of two parts: a public goods and a dictator game, both are played once. After subjects make their initial choices, they can revise them. Before revising, they are allowed to choose among different payoff irrelevant information regarding choices made by other cohorts that differed in class and gender. Our data are consistent with some of the findings in the psychology literature. We find that complexity matters. We find no gender or group effects on conformity rates. However, gender has weak effects when combined with group identity.

The existence of multiple equilibria is one explanation for why some countries are rich while others are poor. This explanation also allows the possibility that changes in political and economic institutions might help poor countries "jump" from a bad economic equilibrium into a better one, permanently increasing their output and income. Experiments can be used to study complex processes like the effect of institutions on economic growth. The control that experiments afford allows structural parameters to be changed, policies to be added and subtracted, and economic outcomes to be precisely measured. In this paper, we study a simple experimental economy in which agents produce output in each period, and can allocate the output between consumption and investment (the experiment builds on the design of Lei and Noussair, 2002, 2003). Capital productivity is higher if total investment is above a threshold. Because of the threshold externality, there are two equilibria - a suboptimal "poverty trap" and an optimal "rich country" equilibrium - which differ by a factor of approximately three in the agent income they create. In baseline sessions, in which agents make independent decisions in a decentralized economy, the economies typically sink into the poverty trap and the optimal equilibrium is never reached. However, the ability to communicate before investing, or to vote on binding "industrial policy" proposals, improves average earnings. Combining both of these simple institutions enables all of the economies to escape the poverty trap. This experimental environment constitutes a platform onto which many more complex features can be added.

This paper tests the separating role of contracts that involve both interest rates and collateral in credit markets with asymmetric information. To test this prediction data from real credit markets and controlled experiments are used. Using a sample of credits to small and medium-sized firms in Valencia, Spain, we relate two different types of contracts with an objective approximation to each ex ante borrower risk, i. e., the real outcome of each loan and other relevant variables. Moreover, two incentive compatible contracts are designed and decisions analyzed under two different experimental treatments, one with moral hazard. Results confirm that borrowers of lower risk choose contracts with higher collateral and a lower interest rate. However, it is ascertained that moral hazard reduces separation.

We report results of one-shot traveler's dilemma game experiments to test the predictions of a model of introspection. The model describes a noisy out-of-equilibrium process by which players reach a decision of what to do in one-shot strategic interactions. To test the robustness of the model and to compare it to other models of introspection without noise, we introduce non-binding advice. Advice has the effect of coordinating all players' beliefs onto a common strategy. Experimentally, advice is implemented by asking subjects who participated in a repeated traveler's dilemma game to recommend an action to subjects playing one-shot games with identical parameters. In contrast to observations, models based on best-response dynamics would predict lower claims than the advised. We show that our model's predictions with and without advice are consistent with the data.

We report results of single interaction Traveler’s Dilemma game experiments with and without expert advice to test the robustness of a model of noisy introspection. The model describes an out-of-equilibrium process with errors by which players reach a decision of what to do in strategic situations. By tracing the process by which players determine what to do, one can find a prediction for single interaction games. Simulations show that the model’s predictions are consistent with experimental data.

In this paper we test Bester's (1985, 1987) prediction about the separating role of contracts that involve both interest rates and collateral requirements in credit markets. To test this prediction we use data from natural credit markets and controlled experiments. Using a sample of credits to small and medium size firms in Valencia, Spain, we relate two different types of contracts with the ex post risk type of the borrower and other relevant variables. We then design two incentive compatible contracts and analyze decisions under two different experimental treatments, one with moral hazard. Our empirical results confirm that borrowers of ex post lower risk choose contracts with higher collateral and lower interest rate. However, we find evidence that the existence of moral hazard could reduce separation.

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