Browsing by Subject "Ambiguity"
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Item A computational modeling approach to understanding the psychological and neural mechanisms underlying directional reasoning about ambiguous events(2016-05) Flagan, Taru Maria; Beer, Jennifer S., 1974-; Eastwick, Paul W; Gosling, Samuel D; Schnyer, David MPeople often view the ambiguities of their social world through a subjective, rather than objective lens. For example, people may construe ambiguous social events in ways that are consistent with their current moods or with the goals they wish to achieve (e.g., Blanchette & Richards, 2010; Pauker, Rule, & Ambady, 2010). Although both mood and motivation direct reasoning about ambiguity, little is known about whether similar mechanisms account for the effects of mood or motivation. Furthermore, similar neural profiles have been associated with mood-congruent ambiguity resolution and motivated reasoning (e.g., Bhanji & Beer, 2012; Hughes & Beer, 2013), but the extent to which these regions support the same underlying processes has not been explored. A deep understanding of the underlying mechanisms has been difficult to assess because previous research has utilized self-report and reaction time measures to explore the effects of mood and motivation on ambiguity (e.g., Butler & Mathews, 1983; Ditto et al., 1998). People have little introspective access to the cognitive processes that lead to their decisions (Nisbett & Wilson, 1977), and reaction time analyses cannot disentangle underlying mechanisms. Therefore a deeper understanding requires alternative approaches. Drift-diffusion modeling (DDM) makes it possible to independently estimate parameters related to two mechanisms theorized to be involved ambiguity construal: expectations and preferential evidence accumulation. This dissertation describes five studies that utilize DDM to examine two overarching research questions: (I) What role do expectations and preferential evidence accumulation play in the influence of mood and motivation on the construal of ambiguity (Studies 1a, 1b, 3, 4) and (II) Are these processes supported by neural regions known to be involved in the effects of mood and motivation on the construal of ambiguity (Studies 2, 4)? The findings support a predicted role for expectations in mood-congruent and motivated construals of ambiguity. In addition, VMPFC supported motivated expectations that contribute to ambiguity construal. The role of preferential evidence accumulation, on the other hand, was less robust. Findings contribute to our understanding of mood-congruent and motivated reasoning about ambiguity and suggest fruitful approaches for future work exploring directed reasoning about ambiguous events.Item Abstraction, representation, and entropy(2012-05) Payzant, Marcus Ray, 1982-; Mutchler, Leslie; Petersen, BradleyThe following graduate report is an overview of my artistic endeavors spanning the past three years at the University of Texas at Austin. While at UT, I have concentrated on making paintings that focus on the relationship between abstraction, representation, and entropy. Using banal, often overlooked cultural objects as subject matter, I paint ambiguous scenes that teeter between disintegration and formation. Representations of banal detritus within an ambiguous natural space become a metaphor for memory, culture, and life and death alluding to unseen forces and, ultimately, a lack of control. Using a combination of random and deliberate decisions, I aim to create a commentary about the unpredictable yet conformist aspects of the world in which we participate.Item Ambiguity, power, and gender roles in the young adult dating scene(2013-12) Steidl, Ellyn Arevalo; Raley, R. KellyIt is well established that patterns of relationship formation in young adulthood are becoming increasingly complex. There is a growing heterogeneity in the types of relationships young adults can form, and there is evidence that the processes of relationship formation are marked by substantial ambiguity. This lack of structure in the young adult dating scene may be accompanied by more flexible gender roles in dating behaviors. Historically men’s roles centered on proactive initiation and women’s roles were characterized by reactive passivity; these gender roles structured the commencement and the progression of early relational ties into formalized unions. However, the deinstitutionalization of dating may have allowed women and men to enact new roles in the pre-relationship phase. This research asks if women and men equally exercise control in both the commencement of relationships and in determining their trajectory. Results indicate that men possess a unique controlling role of the ability to define a relationship, while women typically inhabit a role of clearly communicating their interests levels to men while simultaneously attempting to clarify men’s intentions.Item The effects of payoffs and feedback on the disambiguation of relative clauses(2014-12) Chacartegui Quetglas, Luis; Bannard, ColinThis dissertation investigates two facts about language processing. The Good Enough Approach claims that language users do not form a fully detailed representation of the input unless the task at hand requires it. On the other hand it has been shown that language users display internal preferences when they are faced with ambiguous input, as to what direction disambiguation should take. It has been proposed that these preferences are based on previous experience with similar inputs. This thesis investigates these two issues using tools from the fields of decision making and reinforcement learning. Specifically feedback and payoffs associated with sentence interpretations are manipulated to explore reading behavior, understood as a process of information seeking, and disambiguation choices. In four eye-tracking-reading experiments, the experimental stimuli are sentences containing a relative clause attachment ambiguity. Experiment 1 investigates whether the combination of the degree of ambiguity of a sentence and the possible payoffs, affect people’s reading times for the potentially ambiguous parts of a sentence, as well as their disambiguation choices. Experiment 2 investigates the role of feedback in such processes, a combination related to expected utility maximization. Experiment 3 studies how participants learn from feedback under risky or non-risky conditions. The last experiment investigates whether participants adjust their responses to evidence provided by feedback even overriding their internal initial bias towards a default response.Item Essays on dynamic contracts : allocation of ambiguity and delegation(2016-05) Bhattacharjee, Swagata; STINCHCOMBE, MAXWELL; STAHL, DALE O; BOYARCHENKO, SVETLANA; THOMAS, CAROLINE; ALMAZAN, ANDRESMy dissertation studies the design of contracts in different contexts. It contains two theoretical investigations about contracting under ambiguity: in the context of research partnerships and venture capital financing; and an experimental study to examine delegation of decision rights within organizations. The first chapter studies contract design for innovation under ambiguity. Outsourcing of research is a large and growing trend in knowledge-intensive industries such as the biotechnology and software industries. I model innovation as an ambiguous stochastic process and assume that the commercial firms and research labs differ in their attitude towards ambiguity. I characterize the optimal sequence of short-term contracts and examine how the features of this contract facilitate ambiguity sharing: the dynamic moral hazard problem is mitigated under ambiguity; experimentation stops earlier than is socially optimal; the project may be liquidated even after being granted a patent. I find that redesigning the patent law can not implement the Policymaker’s desired optimum. The second chapter analyzes venture capital investment under ambiguity. A central feature of venture capital financing is the extensive use of control rights as an instrument. In this chapter, I present a model of venture capital financing where investment is allowed to depend on an intermediate ambiguous signal. I show how the presence of ambiguity explains the allocation of control rights if the investor is more ambiguity averse than the entrepreneur. In the third chapter, I discuss how delegation of decision rights can be used as a signal of trust that can be reciprocated by cooperation. First, I theoretically show that in a principal-agent framework, using delegation as a signal is the only Perfect Bayesian Equilibrium that survives forward induction criterion. Then I use experimental methods to test this theoretical prediction. I find that the players do not use delegation very often, thus the forward induction logic is not supported by the observed data. However, once the players are given information about the past sessions, they choose the forward induction equilibrium more often. This suggests that information affects the formation of beliefs and equilibrium selection in Bayesian games.Item Information structures and their effects on consumption decisions and prices(2013-05) Moreno González, Othón M.; Wiseman, Thomas E., 1974-This work analyzes the effects that different information structures on the demand side of the market have on consumption decisions and the way prices are determined. We develop three theoretical models to address this issue in a systematic way. First, we focus our attention on the consumers' awareness, or lack thereof, of substitute products in the market and the strategic interaction between firms competing in prices and costly advertising in such an environment. We find that prior information held by consumers can drastically change the advertising equilibrium predictions. In particular, we provide sufficient conditions for the existence of three types of equilibria, in addition to one previously found in the literature, and provide a necessary condition for a fourth type of equilibrium. Additionally, we show that the effect of the resulting advertising strategies on the expected transaction price is qualitatively significant, although ambiguous when compared to the case of a newly formed market. We can establish, however, that the transaction price is increasing in the size of the smaller firm's captive market. In the second chapter, we study the optimal timing to buy a durable good with an embedded option to resell it at some point in the future, as well as its reservation price, where the agent faces Knightian uncertainty about the process generating the market prices. The problem is modeled as a stopping problem with multiple priors in continuous time with infinite horizon. We find that the direction of the change in the buyer's reservation price depends on the particular parametrization of the model. Furthermore, the change in the buying threshold due to an increase in ambiguity is greater as the fraction of the market at which the agent can resell the good decreases, and the value of the embedded option is decreasing in the perceived level of ambiguity. Finally, we introduce Knightian uncertainty to a model of price search by letting the consumers be ambiguous regarding the industry's cost of production. We characterize the equilibria of this game for high and low levels of the search cost and show that firms extract abnormal profits for low realizations of the marginal cost. Furthermore, we show that, as the search cost goes to zero, the equilibrium of the game under the low cost regime does not converge to the Bertrand marginal-cost pricing. Instead firms follow a mixed-strategy that includes all prices between the high and low production costs.Item Retrieving information from heterogeneous freight data sources to answer natural language queries(2014-12) Seedah, Dan Paapanyin Kofi; Leite, FernandaThe ability to retrieve accurate information from databases without an extensive knowledge of the contents and organization of each database is extremely beneficial to the dissemination and utilization of freight data. The challenges, however, are: 1) correctly identifying only the relevant information and keywords from questions when dealing with multiple sentence structures, and 2) automatically retrieving, preprocessing, and understanding multiple data sources to determine the best answer to user’s query. Current named entity recognition systems have the ability to identify entities but require an annotated corpus for training which in the field of transportation planning does not currently exist. A hybrid approach which combines multiple models to classify specific named entities was therefore proposed as an alternative. The retrieval and classification of freight related keywords facilitated the process of finding which databases are capable of answering a question. Values in data dictionaries can be queried by mapping keywords to data element fields in various freight databases using ontologies. A number of challenges still arise as a result of different entities sharing the same names, the same entity having multiple names, and differences in classification systems. Dealing with ambiguities is required to accurately determine which database provides the best answer from the list of applicable sources. This dissertation 1) develops an approach to identify and classifying keywords from freight related natural language queries, 2) develops a standardized knowledge representation of freight data sources using an ontology that both computer systems and domain experts can utilize to identify relevant freight data sources, and 3) provides recommendations for addressing ambiguities in freight related named entities. Finally, the use of knowledge base expert systems to intelligently sift through data sources to determine which ones provide the best answer to a user’s question is proposed.Item Risk Perception and Willingness to Pay for Removing Arsenic in Drinking Water(2012-10-19) Chen, SihongThis thesis is concerned with (i) how to estimate the perceived mortality risk, (ii) how to calculate the welfare change of mortality risk reduction and (iii) whether ambiguity aversion influences subjects' treatment decision. This study is an important topic in environmental and resource economics, and the attempt to introduce ambiguity preference into the models might shed light on future research in nonmarket valuation. In this study, I estimate the economic value of reducing mortality risk relating to arsenic in drinking water employing contingent valuation in U.S. arsenic hot spots. Re-cent studies have shown that perceived risk is a more reliable variable than scientific assessments of risk when applied to interpret and predict individual's averting behavior. I am also interested in the confidence level of perceived risk, which was elicited and treated as the degree of risk ambiguity in this paper. I develop a formal parametric model to calculate the mean willingness to pay (WTP) for mortality risk reduction, and find weak evidence of ambiguity aversion.Item Three experiments on decision-making under uncertainty in dynamic environments(2013-05) Rosokha, Yaroslav; Stahl, Dale O.This dissertation consists of three economic experiments that investigate behavioral differences in decision making process under risk (uncertainty with known probabilities) and under ambiguity (uncertainty with unknown probabilities). The first and the second chapters present two experiments with subjects choosing between lotteries involving risky and ambiguous urns. Decisions are made in conjunction with a sequence of random draws with replacement, allowing us to track the beliefs of the agents at different moments in time. In the first chapter, we develop and estimate a model of subjective belief updating allowing for base rate fallacy. We find that when updating under ambiguity subjects significantly underweight the new signal, while when updating under compound risk subjects are essentially Bayesian. In the second chapter, we estimate a popular multiple priors model for decision making under ambiguity in dynamic environments. Our estimates suggest a difference in the confidence with which subjects discard the unlikely priors depending on whether an ambiguous urn was presented first or second. Specifically, when an ambiguous urn is presented first, subjects consider more priors during the learning process as compared to when a compound urn is presented first. We also find significant evidence against the hypothesis that human subjects consider only Dirac priors. In the third chapter, we examine the behavior of security dealers in an environment where the level of asymmetric information is viewed as either risk, compound risk, or ambiguity. Using two measures of market liquidity, resiliency and price, we find that duopoly dealer markets are both more resilient to uncertainty about asymmetric information as well as having higher dealer bids compared with monopoly dealer markets for all three uncertainty scenarios. Additionally, we find differences in dealer bidding behavior in duopoly setting depending on whether the uncertainty about informed trading is presented as risk, compound risk, or ambiguity.Item The von Neumann/Morgenstern approach to ambiguity(2011-08) Dumav, Martin; Ẑitković, Gordan; Sirbu, MihaiAn outcome is ambiguous if it is an incomplete description of the probability distribution over consequences. An `incomplete description' is identified with the set of probabilities that satisfy the incomplete description. A choice problem is uncertain if the decision maker is choosing between distributions, and is ambiguous if the decision maker is choosing between sets of probabilities. The von Neumann/Morgenstern approach to uncertain choice problems uses a continuous linear function on probabilities. This paper develops the theory of ambiguous choice problems as a continuous, linear functions on closed convex sets of probabilities. This delivers: a framework encompassing most of the extant ambiguity averse preferences; a complete separation of attitudes towards risk and attitudes toward ambiguity; and generalizations of rst and second order stochastic dominance rankings to ambiguous decision problem. Quasi-concave preferences on sets that satisfy a restricted betweenness property capture variational preferences.