Search

Observed individual behavior in the presence of ambiguity shows insufficient responsiveness to changes in subjective likelihoods. Despite being integral to theoretical models and relevant in many domains, evidence on the causes and determining factors of such likelihood insensitive behavior is scarce. This paper investigates the role of beliefs in the form of ambiguity perception – the extent to which a decision-maker has difficulties assigning a single probability to each possible event – as a potential determinant. Using an experiment, I elicit measures of ambiguity perception and likelihood insensitivity and exogenously vary the level of perceived ambiguity. The results provide strong support for a perception-based explanation of likelihood insensitivity. The two measures are highly correlated at the individual level, and exogenously increasing ambiguity perception increases insensitivity, suggesting a causal relationship. In contrast, ambiguity perception is unrelated to ambiguity aversion – the extent to which a decision-maker dislikes the presence of ambiguity. [ABSTRACT FROM AUTHOR]

Although much of the theoretical and applied literature involving decision under ambiguity works under the assumption of uncertainty aversion, experimental evidence suggests that it is not a universal behavioural trait. This paper introduces and axiomatises the family of α -UA (for α -Uncertainty Attitude) preferences: a simple extension of uncertainty averse preferences with a Hurwicz-style mixing coefficient, so as to admit a richer range of uncertainty attitudes. The parameters of the model are uniquely identified in our characterisation. It provides, in the Hurwicz α -maxmin EU special case, a new resolution of a long-standing identification problem. It also yields novel models, including extensions of variational and multiplier preferences. Comparative statics support the interpretation of the mixing coefficient as an index of imprecision aversion. In a standard portfolio problem, the model yields the intuitive relationship between imprecision aversion and investment in an uncertain asset: as the former increases, the latter decreases. [ABSTRACT FROM AUTHOR]

This paper provides a micro-foundation for approximate incentive compatibility using ambiguity aversion. In particular, we propose a novel notion of approximate interim incentive compatibility, approximate local incentive compatibility , and establish an equivalence between approximate local incentive compatibility in a Bayesian environment and exact interim incentive compatibility in the presence of a small degree of ambiguity. We then apply our result to the implementation of efficient allocations. In particular, we identify two economic settings—including ones in which approximately efficient allocations are implementable and ones in which agents are informationally small—in which efficient allocations are approximately locally implementable when agents are Bayesian. Applying our result to those settings, we conclude that efficient allocations are exactly implementable when agents perceive a small degree of ambiguity. [ABSTRACT FROM AUTHOR]

Ambiguous language is ubiquitous and often deliberate. Recent theoretical work (Bose and Renou, 2014 ; Kellner and Le Quement, 2018 ; Beauchêne et al., 2019) has shown how language ambiguation can improve outcomes by mitigating conflict of interest. Our experiment finds a significant effect of language ambiguation on subjects who are proficient at Bayesian updating. For ambiguity averse subjects within this population, a significant part of this effect operates via the channel of subjects' desire to reduce ambiguity. For both ambiguity averse and neutral subjects within this population, an additional behavioral channel is also present. [ABSTRACT FROM AUTHOR]

We consider the computability and complexity of decision questions for Probabilistic Finite Automata (PFA) with sub-exponential ambiguity. We show that the emptiness problem for strict and non-strict cut-points of polynomially ambiguous commutative PFA remains undecidable, implying that the problem is undecidable when inputs are from a letter monotonic language. We show that the problem remains undecidable over a binary input alphabet when the input word is over a bounded language, in the noncommutative case. In doing so, we introduce a new technique based upon the Turakainen construction of a PFA from a Weighted Finite Automaton which can be used to generate PFA of lower dimensions and of sub-exponential ambiguity. We also study freeness/injectivity problems for polynomially ambiguous PFA and study the border of decidability and tractability for various cases. [ABSTRACT FROM AUTHOR]

• The findings highlight the semantic relation and grammatical factor in the brain's representation of lexical ambiguities. • Compared to unambiguous words, homonyms and polysemous activate the inferior frontal gyri and posterior temporal region. • Compared to polysemous words, homonyms elicit increased activity in dorsal prefrontal and posterior parietal cortices. • Meanings of homonyms with different syntactic categories are represented distinctively in frontal and temporal cortices. In human languages, it is a common phenomenon for a single word to have multiple meanings. This study used fMRI to investigate how the brain processed different types of lexical ambiguity, and how it differentiated the meanings of ambiguous words. We focused on homonyms and polysemy that differed in the relatedness among multiple meanings. Participants (N = 35) performed a prime-target semantic relatedness task, where a specific meaning of an ambiguous word was primed. Results showed that homonyms elicited greater activation in bilateral dorsal prefrontal and posterior parietal cortices than polysemous words, suggesting that these regions may be more engaged in cognitive control when the meanings of ambiguous words are unrelated. Multivariate pattern analysis further revealed that meanings of homonyms with different syntactic categories were represented differently in the frontal and temporal cortices. The findings highlighted the importance of semantic relations and grammatical factors in the brain's representation of lexical ambiguities. [ABSTRACT FROM AUTHOR]

Semi-consistent conditional preferences are inconsistent enough for different ambiguity attitudes to manifest themselves in different behavior and consistent enough for information to be generically valuable. To simultaneously achieve these two desiderata I assume exactly one type of dynamic inconsistency: agents do not update their preferences upon learning independent randomization outcomes. [ABSTRACT FROM AUTHOR]

This paper explores multi-stage incomplete information games with common ambiguous information about states or types and ambiguity averse players. We characterize a belief formation process that allows players to take their knowledge about the structure of the game into account. This process leads to subjective rectangular ex-ante belief sets for all players. We show that given these sets of beliefs, players behave dynamically consistent. Therefore, using our belief formation process, we can extend the concept of sequential equilibria to multi-stage ambiguous incomplete information games. Furthermore, we characterize assumption under which sequential rationality implies rectangularity. [ABSTRACT FROM AUTHOR]

In the context of normal-form games with complete information, we introduce a notion of correlated equilibrium that allows partial delegation to a mediator and ambiguity in the correlation device. Without ambiguity, the sets of equilibrium action distributions are equivalent to those for coarse correlated equilibrium (Moulin and Vial, 1978). With correlation devices that incorporate ambiguity, any action distribution that Pareto dominates a coarse correlated equilibrium or a correlated equilibrium (Aumann, 1974), can be approximated with an arbitrary degree of precision using the proposed equilibrium notion. These approximations are attained in one-shot, static strategic interactions, and do not require repeated play. We also analyze such equilibria when the set of feasible posteriors is exogenously constrained, which yields, as a special case, a definition and characterization of an "ambiguous correlated equilibrium" that does not require delegation to the mediator. [ABSTRACT FROM AUTHOR]

Outsourcing of research is commonly observed in knowledge-intensive industries such as biotech. We model innovation as an ambiguous stochastic process with dynamically consistent updating. We assume that the research labs are less ambiguity averse than the commercial firms. We characterize the optimal sequence of short-term contracts governing innovation, and show how it facilitates ambiguity-sharing. This ambiguity sharing agreement mitigates the dynamic moral hazard problem, resulting in monotonically decreasing investment and preventing equilibrium delay. Compared to an ambiguity-neutral policymaker's benchmark, the research alliances stop experimenting too early, and may liquidate the project even after being patented. The problems are structural, redesigned patent laws cannot solve both of these problems. [ABSTRACT FROM AUTHOR]

• The lack of a consensus definition for character strengths creates ambiguity. • Twelve criteria have been proposed for defining character strengths. • Using just one or two of these can define character strengths with 74% precision. • Yet, they fall short in differentiating character strengths from personality. • We recommend using one of our five working definitions for character strengths. Character strengths lack a consensual definition, creating ambiguity in psychological research. This exploratory study tests whether previously discussed ideas about character strengths' shared qualities (e.g., fulfilling, morally valued, traitlike) distinguish them from related concepts, such as the Big Five. Ten laypersons rated 12 of these "criteria" across 80 character strengths adjectives and 170 that pertained to the Big Five, emotions, anatomy, and bodily states. Results indicate that one or two criteria suffice to define character strengths with about 74% accuracy. However, these criteria could not distinguish character strengths from the Big Five, suggesting they may belong to the same conceptual category. We recommend adopting one of five working definitions based on these findings when introducing character strengths in future research. [ABSTRACT FROM AUTHOR]

The global imperative to mitigate carbon emissions for sustainable development has spurred extensive research into economic, social, and energy-related factors. However, prior studies present a complex landscape, yielding mixed conclusions regarding the influence of geopolitical risk, natural resource rents, corrupt governance, and energy intensity. To untangle this ambiguity, we construct a research model grounded in the Environmental Kuznets Curve, employing panel data from 38 countries spanning 2002 to 2020. Employing panel quantile regression models, we directly assess the impact of identified factors. Our findings affirm the alignment between economic growth and carbon emissions, supporting the Environmental Kuznets Curve hypothesis. Notably, increased geopolitical risk and energy intensity correlate with heightened carbon emissions over time, while corruption governance and natural resource rents exhibit a mitigating effect. Additionally, our study explores the indirect impact of these factors using a panel threshold regression model. Results indicate a diminishing influence of economic growth on carbon emissions. Intriguingly, natural resource rents initially curtail, then amplify the connection between economic growth and carbon emissions. Conversely, rising energy intensity magnifies the relationship between economic expansion and carbon emissions. • Linear and nonlinear models were employed to explore the carbon emission influencing factors. • Explored the direct and indirect effects of geopolitical risk, natural resource rents, corruption and energy intensity on carbon emissions. • Natural resource rents, corruption governance in favour of lower carbon emissions, geopolitical risk and energy intensity in contrast. • Natural resource rents, corruption and geopolitical risks affect the relationship between economic growth and carbon emissions. [ABSTRACT FROM AUTHOR]

Ambiguity is an important notion in sociology, denoting situations where social actors and groups carry on without shared meaning. The current article applies this concept to the context of religiosity during people's upbringing, recognizing that multiple factors make family-level religion a complex experience. Indeed, though recent research portrays household religiosity in childhood as a sociocultural exposure with long-term implications for well-being, existing studies have yet to incorporate multiple inputs to consider the cohesiveness of that exposure. Using twin data from a national sample, we investigate whether consistency in recalled household religiosity is associated with mid-life flourishing. Multi-level linear regression models reveal that similarity in twin reports matter, above and beyond the actual level of religiosity individuals report and net of dis/similarity across other childhood recollections. We conclude that coherence in religious upbringing—whether religion was understood to be important or not—is a key ingredient for thriving later in life and then reflect more broadly on manifestations of sociocultural ambiguity in families and in larger social units. [ABSTRACT FROM AUTHOR]

This paper studies a multi-state binary choice experiment in which in each state, one alternative has well understood consequences whereas the other alternative has unknown consequences. Subjects repeatedly receive feedback from past choices about the consequences of unfamiliar alternatives but this feedback is aggregated over states. Varying the payoffs attached to the various alternatives in various states allows us to test whether unfamiliar alternatives are discounted and whether subjects' use of feedback is better explained by similarity-based reinforcement learning models (in the spirit of the valuation equilibrium, Jehiel and Samet, 2007) or by some variant of Bayesian learning model. Our experimental data suggest that there is no discount attached to the unfamiliar alternatives and that similarity-based reinforcement learning models have a better explanatory power than their Bayesian counterparts. [ABSTRACT FROM AUTHOR]

The study of consistent individual differences has become an important focus in research on animal behaviour. These behavioural differences are typically measured through standardized testing procedures. One frequently used paradigm is the novel object test, in which animals are exposed to unfamiliar objects and their reaction is quantified. We used meta-analysis to evaluate how reliably novel object trials quantify individual differences. Overall, we found repeatability of responses to novel objects was strong and significant and was larger in short-term than in long-term studies. Average sample size and long-term estimates have both increased over the past three decades. Most short-term studies used different novel objects in repeated presentations, while long-term studies used either the same or different novel objects almost equally often. Novelty, the time interval between trials and their interaction together explained little of the total heterogeneity, while between-study heterogeneity remained large. Overall, novel object trials reliably estimate individual differences in behaviour, but results were very heterogeneous even within the same study species, suggesting susceptibility to unknown details in test conditions. Most studies that use novel object trials in a foraging context label the trait as neophobia, while novel object trials in a neutral context are labelled variously as shyness–boldness, exploration–avoidance or neophilia. To avoid ambiguity, we argue for the use of object–neophobia for trials near resources and object–neophilia for trials in a neutral context as the most specific labels for novel object responses. • We present a meta-analysis for novel object tests and discuss different practices. • Novel object tests efficiently quantify individual differences in behaviour. • Experimental decisions do not significantly affect the repeatability of behaviour. • There was a substantial amount of unexplained heterogeneity. • We also summarize the terminology used to describe responses to novel objects. [ABSTRACT FROM AUTHOR]

The emptiness and containment problems for probabilistic automata are natural quantitative generalisations of the classical language emptiness and inclusion problems for Boolean automata. It is known that both problems are undecidable. We provide a more refined view of these problems in terms of the degree of ambiguity of probabilistic automata. We show that a gap version of the emptiness problem (known to be undecidable in general) becomes decidable for automata of polynomial ambiguity. We complement this positive result by showing that emptiness remains undecidable when restricted to automata of linear ambiguity. We then turn to finitely ambiguous automata and give a conditional decidability proof for containment in case one of the automata is assumed to be unambiguous. Part of our proof relies on the decidability of the theory of real exponentiation, proved, subject to Schanuel's Conjecture, by Macintyre and Wilkie. [ABSTRACT FROM AUTHOR]

We propose a new solution concept, called Context-Dependent Equilibrium Under Ambiguity (CD-EUA), for strategic games where players' beliefs may be influenced by exogenous context-related information. Players' beliefs about the strategic behavior of their opponents are represented by belief functions. The notion of belief functions allows us to combine exogenous context information in the spirit of Schelling (1960) with endogenous equilibrium beliefs about the opponents' behavior in analogy to the standard Nash equilibrium. For any finite strategic game, we prove existence of a CD-EUA for any context information and any degree of confidence in it. Moreover, we show continuity of the equilibrium correspondence. Finally, we illustrate how CD-EUA can be applied to different types of context information in games by explaining some stylized facts from experimental research on coordination. [ABSTRACT FROM AUTHOR]

Neoclassical economic theory assumes that whenever agents tackle dynamic decisions under ambiguity, preferences are represented by the Subjective Expected Utility (SEU) model and prior beliefs are updated according to Bayes rule, upon the arrival of partial information. Nevertheless, when one considers non-neutral ambiguity attitudes, either the axiom of dynamic consistency or of consequentialism should be relaxed. Using data from an economic experiment on dynamic choice under ambiguity, we study which of the two rationality axioms people violate, along with the question of whether this violation is part of a conscious planning strategy or not. The combination of the two, allows us to classify non-SEU subjects to three behavioural types: resolute, naïve and sophisticated. The hypothesis of Bayesian updating is rejected for more than half of the experimental population. For ambiguity non-neutral subjects, we find that the majority are sophisticated, a few are naïve and very few are resolute. [ABSTRACT FROM AUTHOR]

Current non-stationary load models based on the evolutionary power spectral density (EPSD) may lead to overestimation and ambiguity of structural responses. The quasi-stationary harmonizable process with its Wigner-Ville spectrum (WVS) and Loève spectrum, which do not suffer from the deficiencies of EPSD, is suitable for modeling non-stationary loads and analyzing their induced structural responses. In this study, the multi-taper S-transform (MTST) method for estimating WVS and Loève spectrum of multi-variate quasi-stationary harmonizable processes is presented. The analytical biases and variances of the WVS, Loève spectrum, and time-invariant and time-varying coherence estimators from the MTST method are provided under the assumption that the target multi-variate harmonizable process is Gaussian. Using a numerical case of a bivariate harmonizable wind speed process, the superiority and reliability of the MTST method are demonstrated through comparisons with several existing methods for the WVS and Loève spectrum estimations. Finally, the MTST method is applied to two pieces of ground motion acceleration records measured during the Turkey earthquake in 2023. [ABSTRACT FROM AUTHOR]

A growing literature demonstrates reluctant giving: Many people who voluntarily give to charity no longer do so when they have an excuse not to give. The mechanisms of reluctance, however, remain unclear. Consistent with this literature, we found that injecting attributional ambiguity into a real charitable decision significantly reduces donations. Participants in our studies (N = 2147) faced a binary choice between options for distributing money between themselves and a charity, with one option giving more to a charity and the other leaving more for themselves. Borrowing from a classic attributional ambiguity paradigm, we manipulated whether the charity involved was the same for both options or different, giving participants the possible excuse of keeping more money due to preferring one charity over another. Participants indeed kept more for themselves when there were two different charities, regardless of which charity was associated with the more self-beneficial option, ostensibly revealing a hidden preference for selfishness. Using incentive compatible elications, we found no evidence that participants used the excuse of preferring one charity to another to justify their choices. Instead, we find that attributional ambiguity weakened perceptions that there is a norm against keeping more money in the task, both among decision makers and disinterested third parties. We conclude that attributional ambiguity lowers donations by relieving internalized social pressure to give. [ABSTRACT FROM AUTHOR]

A sidereal rotation counting approach is demonstrated by resolving an ambiguity in the synodic rotation period of Koronis family member (3032) Evans, whose rotation lightcurves' features did not easily distinguish between doubly- and quadruply-periodic. It confirms that Evans's spin rate does not exceed the rubble-pile spin barrier and thus presents no inconsistency with being a ∼ 14-km reaccumulated object. The full spin vector solution for Evans is comparable to those for the known prograde low-obliquity comparably-fast rotators in the Koronis family, consistent with having been spun up by YORP thermal radiation torques. • Case study analysis using lightcurve epochs to resolve an ambiguous rotation period. • Sidereal rotation counting identifies the alias period even for symmetric lightcurves. • Spin rate of (3032) Evans does not exceed the rubble-pile spin barrier. • Spin vector of Evans is consistent with spin-up by YORP thermal radiation torques. [ABSTRACT FROM AUTHOR]

Data assimilation can reduce the model-form errors of RANS simulations. A spatially distributed corrective parameter field can be introduced into the closure model, whose optimal values can be efficiently found by an adjoint method and gradient-based optimization. When assimilating experimental data, which in most cases are sparsely distributed or based on a low-resolution grid, the inverse problem is highly underdetermined and thus ambiguous. Therefore, to reduce the ambiguity, regularization is required. Established regularization approaches such as total variation and Sobolev gradient methods can produce smooth and physically meaningful velocity fields in many cases. However, if the measurements are located close to walls, spiky and unphysical wall shear stress profiles can occur. A new regularization strategy based on a piecewise linear approximation of the corrective field is proposed. This method is shown to lead to a very accurate free stream velocity field and smooth wall shear stress profiles. The resulting skin friction drag error for the case of flow over periodic hills was around 1.38% which is seven times lower than the error obtained with the Sobolev gradient and two orders of magnitude lower than that obtained with the other two methods. [ABSTRACT FROM AUTHOR]

We consider the problem of phase retrieval from magnitudes of short-time Fourier transform (STFT) measurements. It is well-known that signals are uniquely determined (up to global phase) by their STFT magnitude when the underlying window has an ambiguity function that is nowhere vanishing. It is less clear, however, what can be said in terms of unique phase-retrievability when the ambiguity function of the underlying window vanishes on some of the time-frequency plane. In this note, we demonstrate that by considering signals in Paley–Wiener spaces, it is possible to prove new uniqueness results for STFT phase retrieval. Among those, we establish a first uniqueness theorem for STFT phase retrieval from magnitude-only samples for real-valued signals. [ABSTRACT FROM AUTHOR]

This paper studies minimax regret traders in a sealed bid double auction. Unlike the expected utility maximizers that populate typical market models, these traders do not determine their actions using a single prior. The analysis proves that, with no restrictions on beliefs about others' types and strategies, minimax regret traders will not converge to price-taking as the size of the market increases, contrary to standard economic intuition. In fact, minimax regret traders' bids and asks are invariant to the number of traders in the market. Thus, the robustness of the sealed bid double auction is sensitive to traders' preferences. [ABSTRACT FROM AUTHOR]

This paper examines the difference between strategic ambiguity as in game theory and ambiguity arising in individual decisions. We identify a new, non-strategic component underlying all strategic ambiguities, called social ambiguity. We recommend controlling for it to better identify strategic causes. Thus, we shed new light on Bohnet and Zeckhauser's betrayal aversion in the trust game. We first show theoretically that, contrary to preceding claims in the literature, ambiguity attitudes can play a role here. We then show experimentally that social ambiguity, rather than betrayal aversion, can explain our empirical findings. Using our new control, we identify the unique effect of strategic ambiguity. Strategic complexity increases ambiguity perception and thus increases people's likelihood insensitivity when making decisions under strategic ambiguity. Our results show the usefulness of controlling for ambiguity attitudes before speculating on strategic factors. [ABSTRACT FROM AUTHOR]

The famous conflict between dynamic consistency and ambiguity purportedly undermines these models' normative credibility, and challenges their use in economic applications. Dynamic consistency concerns preferences over contingent plans: so what counts are the contingencies the decision maker envisages – and plans for – rather than independently fixed contingencies, as implicitly assumed in standard formalisations. An appropriate formulation of dynamic consistency resolves the aforementioned conflict, hence undermining the criticisms of ambiguity models based on it. Moreover, it provides a principled justification for the restriction to certain families of beliefs in applications of these models in dynamic choice problems. Finally, it supports a new analysis of the value of information under ambiguity, showing that decision makers may only turn down information if it has an opportunity cost, in terms of the compromising of information they had otherwise expected to receive. [ABSTRACT FROM AUTHOR]

Economic predictions often hinge on two intuitive premises: agents rule out the possibility of others choosing unreasonable strategies ('strategic reasoning'), and prefer strategies that hedge against unexpected behavior ('cautiousness'). These two premises conflict and this undermines the compatibility of usual economic predictions with reasoning-based foundations. This paper proposes a new take on this classical tension by interpreting cautiousness as robustness to ambiguity. We formalize this via a model of incomplete preferences, where (i) each player's strategic uncertainty is represented by a possibly non-singleton set of beliefs and (i i) a rational player chooses a strategy that is a best-reply to every belief in this set. We show that the interplay between these two features precludes the conflict between strategic reasoning and cautiousness and therefore solves the inclusion-exclusion problem raised by Samuelson (1992). Notably, our approach provides a simple foundation for the iterated elimination of weakly dominated strategies. [ABSTRACT FROM AUTHOR]

Proper scoring rules incentivize truthful probability reports from risk-neutral individuals. For individuals with much more general preferences (including risk and ambiguity aversion) we use duality techniques to characterize the optimal report in any proper scoring rule. We apply this characterization to several well-known families of preferences, and provide several applications. In particular, for the case of CARA and CRRA preferences we (1) can back out true beliefs from optimal reports, (2) show that the quadratic scoring rule minimizes deviations from truthfulness, and (3) provide a two-step procedure in which the agent reports her risk aversion parameter and her belief truthfully. [ABSTRACT FROM AUTHOR]

We ran experiments that gave subjects a straight-forward and simple opportunity to hedge away ambiguity in an Ellsberg-style experiment. Subjects had to make bets on the combined outcomes of a fair coin and a draw from an ambiguous urn. By modifying the timing of the draw, coin flip, and decision, we are able to test the reversal-of-order axiom. Our main result is that the reversal-of-order axiom seems to hold. We also confirm low levels of ambiguity hedging despite the relative obviousness of the opportunity. [ABSTRACT FROM AUTHOR]

We study whether the basic tenets of the theory of zero-sum games are still valid when players are uncertainty averse. We focus on games with one-sided information, in which the uninformed player is uncertain about the state of nature. Uncertainty aversion turns the underlying zero-sum game into a many-player, non-zero-sum game. We show that the uninformed player has a unique equilibrium payoff. We provide conditions under which there is a unique equilibrium payoff vector. [ABSTRACT FROM AUTHOR]

• The ability to switch per se is present from the age of 6 across perceptual tasks. • Perceptual switching rate increases between 6 and 10 years of age across tasks. • Perceptual switching rate across tasks differs in a task specific manner. • Perceptual switching rate is not predicted by executive functions or creativity. • Perceptual switching in children has task specific characteristics. The phenomenon of perceptual bistability provides insights into aspects of perceptual processing not normally accessible to everyday experience. However, most experiments have been conducted in adults, and it is not clear to what extent key aspects of perceptual switching change through development. The current research examined the ability of 6-, 8-, and 10-year-old children (N = 66) to switch between competing percepts of ambiguous visual and auditory stimuli and links between switching rate, executive functions, and creativity. The numbers of switches participants reported in two visual tasks (ambiguous figure and ambiguous structure from motion) and two auditory tasks (verbal transformation and auditory streaming) were measured in three 60-s blocks. In addition, inhibitory control was measured with a Stroop task, set shifting was measured with a verbal fluency task, and creativity was measured with a divergent thinking task. The numbers of perceptual switches increased in all four tasks from 6 to 10 years of age but differed across tasks in that they were higher in the verbal transformation and ambigous structure-from-motion tasks than in the ambigous figure and auditory streaming tasks for all age groups. Although perceptual switching rates differed across tasks, there were predictive relationships between switching rates in some tasks. However, little evidence for the influence of central processes on perceptual switching was found. Overall, the results support the notion that perceptual switching is largely modality and task specific and that this property is already evident when perceptual switching emerges. [ABSTRACT FROM AUTHOR]

The genus Chelonibia , informally referred to as the turtle barnacles, was historically subdivided into four species by both morphological differentiation and host affinity. More recent studies, however, hypothesized that three of these barnacle species – C. testudinaria , C. manati , and C. patula – comprise a single species, C. testudinaria , that exhibits host-specific ecophenotypic plasticity. In this study, we examined both morphological and molecular datasets to assess whether host attachment or genetic differentiation best explains the morphotypes assigned to C. testudinaria and C. manati. For morphology, we compared 11 mensural test and cirral characters from 71 C. testudinaria and 25 C. manati specimens identified by the previously established absence or presence of a ridged external dorsal surface. The two morphotypes overlapped in overall body size, although C. testudinaria averaged significantly larger and C. manati exhibited relatively longer cirri. Discriminant function analyses (DFA) showed strong but incomplete differentiation (92.6% classification success), with one C. manati morphotype collected from a sea turtle classified with high confidence as C. manati. Thus, the morphological data contradict the host-specificity hypothesis. Genetic analyses using three target loci (16s, 28s, COI) from the mitochondrial and nuclear genomes, as well as a single concatenated sequence of >1600 bp, likewise failed to support genetic differentiation between the two morphotypes within the Atlantic sample. With inclusion of a broader sample of Atlantic C. testudinaria and C. manati and Pacific C. testudinaria barnacles, we found strong population distinction between the ocean basins without morphotype separation. Results of the present study suggest that Balanomorph barnacle taxonomy, especially of endosymbiont species, requires further study, as neither phenotypic plasticity nor genetic differentiation accounted for existence of the two distinct morphotypes. • Chelonibia barnacles collected from epibiotic hosts do not fully match the expected phenotype as described in the literature. • Discriminate function analysis identifies turtle-associated barnacles with typical manatee-associated morphology. • Evidence suggests that host-specific phenotypic plasticity for characterization of C. testudinaria requires reevaluation. • Morphological species characterization may have greater importance than molecular divergence for barnacle speciation. [ABSTRACT FROM AUTHOR]

• Young adults are sensitive to the reducibility of uncertainty during belief updating. • Updating processes are quasi-optimal and valence-dependent. • Neural responses in frontoparietal regions show valence-dependent recruitments. • Valence asymmetry at behavioral and neural levels is correlated. Selective use of new information is crucial for adaptive decision-making. Combining a gamble bidding task with assessing cortical responses using functional near-infrared spectroscopy (fNIRS), we investigated potential effects of information valence on behavioral and neural processes of belief and value updating during uncertainty reduction in young adults. By modeling changes in the participants' expressed subjective values using a Bayesian model, we dissociated processes of (i) updating beliefs about statistical properties of the gamble, (ii) updating values of a gamble based on new information about its winning probabilities, as well as (iii) expectancy violation. The results showed that participants used new information to update their beliefs and values about the gambles in a quasi-optimal manner, as reflected in the selective updating only in situations with reducible uncertainty. Furthermore, their updating was valence-dependent: information indicating an increase in winning probability was underweighted, whereas information about a decrease in winning probability was updated in good agreement with predictions of the Bayesian decision theory. Results of model-based and moderation analyses showed that this valence-dependent asymmetry was associated with a distinct contribution of expectancy violation, besides belief updating, to value updating after experiencing new positive information regarding winning probabilities. In line with the behavioral results, we replicated previous findings showing involvements of frontoparietal brain regions in the different components of updating. Furthermore, this study provided novel results suggesting a valence-dependent recruitment of brain regions. Individuals with stronger oxyhemoglobin responses during value updating was more in line with predictions of the Bayesian model while integrating new information that indicates an increase in winning probability. Taken together, this study provides first results showing expectancy violation as a contributing factor to sub-optimal valence-dependent updating during uncertainty reduction and suggests limitations of normative Bayesian decision theory. [ABSTRACT FROM AUTHOR]

• Positive judgments of ambiguous faces had strong fMRI activation in the CO network. • Accompanied by a second, late peak following final decision on emotional valence. • Supports the initial negativity hypothesis, showing positivity is a controlled process. • CO network activation reflects reporting of valence decision late in the trial. Cortical task control networks, including the cingulo-opercular (CO) network play a key role in decision-making across a variety of functional domains. In particular, the CO network functions in a performance reporting capacity that supports successful task performance, especially in response to errors and ambiguity. In two studies testing the contribution of the CO network to ambiguity processing, we presented a valence bias task in which masked clearly and ambiguously valenced emotional expressions were slowly revealed over several seconds. This slow reveal task design provides a window into the decision-making mechanisms as they unfold over the course of a trial. In the main study, the slow reveal task was administered to 32 young adults in the fMRI environment and BOLD time courses were extracted from regions of interest in three control networks. In a follow-up study, the task was administered to a larger, online sample (n = 81) using a more extended slow reveal design with additional unmasking frames. Positive judgments of surprised faces were uniquely accompanied by slower response times and strong, late activation in the CO network. These results support the initial negativity hypothesis, which posits that the default response to ambiguity is negative and positive judgments are associated with a more effortful controlled process, and additionally suggest that this controlled process is mediated by the CO network. Moreover, ambiguous trials were characterized by a second CO response at the end of the trial, firmly placing CO function late in the decision-making process. [ABSTRACT FROM AUTHOR]

• We examined the relationship between conceptual and lexical representations. • Participants viewed a sequence of 2 pictures and decided if they were related. • Some of the object names were ambiguous in orthography, phonology, or both. • N400 revealed that the lexical status of the self generated object names affected semantic decisions. • N230 revealed that conceptual access occurred 200 ms before lexical effects. We examined whether meanings automatically activate linguistic forms, and whether these forms affect semantic decisions. Participants were presented sequentially with pairs of pictures and decided whether the objects in the pictures were related. At no point did they name the pictures. The object names of the experimental stimuli were ambiguous either in orthography (homographs), phonology (homophones), or both (homonyms), or unambiguous. We show that the lexical characteristics of the name of the objects affect a semantic decision about real world relations, in an online measure (N400), in addition to offline behavioral measures. We show a dissociation between conceptual and lexical recognition, where an earlier component (N230), was affected by relatedness, but was not sensitive to the lexical characteristics. We interpret this as supporting the hypothesis that semantic recognition occurs before the automatic lexical activation of the object name, but that once linguistic representations are activated, they affect semantic integration. [ABSTRACT FROM AUTHOR]

Word-class ambiguous words engender greater processing time and fMRI (BOLD signal) activation than unambiguous ones. Theoretical accounts of this phenomenon suggest that words with multiple meanings (1) are associated with multiple lexical entries and thus require greater selection demands, or (2) undergo computationally expensive grammatical processes that convert words from one word-class to another. Using an fMRI grammaticality judgment task, we tested these accounts by examining word-class ambiguous polysemic (e.g., brush) and homonymic (e.g., bear) verbs, and unambiguous verbs (e.g., bake). Results showed that ambiguous verbs evoked longer response times and greater neural activation in the left inferior frontal and parietal gyri. However, homonymic verbs also showed increased left inferior frontal and temporal neural activations compared to polysemic verbs. This indicates that rather than having multiple lexical representations like homonyms, polysemic verbs may share a core representation with their noun counterparts. [ABSTRACT FROM AUTHOR]

The term "belief function" is generally used to refer to a class of capacities that can be viewed as representing ambiguity averse preferences. This paper introduces a definition of equilibrium for normal-form games with ambiguous beliefs, where belief functions are used to describe strategic uncertainty. To capture independence of strategies and beliefs, a novel notion of a "strategic product integral" is introduced for belief functions, based on their Möbius transforms, and shown to be different from the Choquet integral of an appropriate product capacity. A characterization of the integral in terms of maxmin expected utility expressed relative to elements of the cores of the respective belief functions, is also presented. The resulting equilibrium notion relies on Möbius transforms to embed objectively chosen probabilistic mixed strategies into ambiguous beliefs of opponents about these strategies, while incorporating stronger consistency requirements than those imposed by previous definitions of equilibria under ambiguity. [ABSTRACT FROM AUTHOR]

We consider a game in extensive form recurrently played by agents who are randomly drawn from large populations and matched. We assume that preferences over actions at any information set admit a smooth-ambiguity representation in the sense of Klibanoff et al. (2005) , which may induce dynamic inconsistencies. We take this into account in our analysis of self-confirming equilibrium (SCE) given players' feedback about the path of play. Battigalli et al. (2015) show that the set of SCE's of a simultaneous-move game with feedback expands as ambiguity aversion increases. We show by example that SCE in a sequential game is not equivalent to SCE applied to the strategic form of such game, and that the previous monotonicity result does not extend to general sequential games. Still, we provide sufficient conditions under which the monotonicity result holds for SCE. [ABSTRACT FROM AUTHOR]

Highlights • We assessed how ambiguity tolerance (AT) relates to Big 5 personality traits. • AT related positively to O and E, and negatively to N. • O predicted ambiguity tolerance controlling for intelligence. • Behavioral AT didn't correlate with self-reported AT or Big 5 measures. • These results support predictions of psychological entropy theories of personality. Abstract The present study investigated whether ambiguity tolerance relates to personality traits that are theoretically grounded in fear (neuroticism) or attraction (openness to experience; extraversion) for the unknown. Our hypotheses were supported for self-report measures (and openness to experience predicted ambiguity tolerance controlling for intelligence), but behavioral choice measures of ambiguity tolerance demonstrated poor reliability and were unrelated to self-reported ambiguity tolerance and basic personality traits. An exploratory network analysis revealed that ambiguity tolerance was more strongly related to the intellectual curiosity (vs. aesthetic appreciation) facet of openness to experience, and the assertiveness (vs. energy or sociability) facet of extraversion. Our findings reinforce the fragmented literature in this area, and support predictions derived from psychological entropy theories of personality. [ABSTRACT FROM AUTHOR]

Abstract I study how risk preferences and the level of ambiguity influence ambiguity attitudes in Uzi Segal's recursive second-order non-expected utility model. It is shown that the negative certainty independence axiom for risk preferences is equivalent to a global form of ambiguity aversion that entails ambiguity averse behavior irrespective of the state space and the decision maker's second-order belief. Thus, the second-order version of the cautious expected utility model is the only subclass of Segal's theory that robustly predicts ambiguity aversion. Moreover, a mean-preserving spread operation over second-order beliefs, which corresponds to a particular way of increasing the level of ambiguity, is equivalent to increasing the relative strength of ambiguity aversion for each possible specification of risk preferences within the cautious expected utility model. An application of the latter result establishes a negative relation between participation rates in an asset market and the level of ambiguity concerning the distribution of returns. [ABSTRACT FROM AUTHOR]

Abstract We are often presented with choices that differ in their more immediate versus future consequences. Interestingly, in everyday-life, ambiguity about the exact timing of such consequences frequently occurs, yet it remains unknown whether and how time-ambiguity influences decisions and their underlying neural correlates. We developed a novel intertemporal fMRI choice task in which participants make choices between sooner-smaller (SS) versus later-larger (LL) monetary rewards with systematically varying levels of time-ambiguity. Across trials, delay information of the SS, the LL, or both rewards was either exact (e.g., in 5 weeks), of low ambiguity (4 week range: e.g., in 3–7 weeks), or of high ambiguity (8 week range: e.g., in 1–9 weeks). Choice behavior showed that the majority of participants preferred options with exact delays over those with ambiguous delays, indicating time-ambiguity aversion. Consistent with these results, the ventromedial prefrontal cortex showed decreased activation during ambiguous versus exact trials. In contrast, intraparietal sulcus activation increased during ambiguous versus exact trials. Furthermore, exploratory analyses suggest that more time-ambiguity averse participants show more insula and dorsolateral prefrontal cortex activation during subjective value (SV)-coding of ambiguous versus exact trials. Lastly, the best-fitting computational choice models indicate that ambiguity impacts the SV of options via time perception or via an additive ambiguity-related penalty term. Together, these results provide the first behavioral and neural signatures of time-ambiguity, pointing towards a unique profile that is distinct from impatience. Since time-ambiguity is ubiquitous in real-life, it likely contributes to shortsighted decisions above and beyond delay-discounting. Highlights • We investigate time-ambiguity: uncertainty about when an outcome will occur. • Time-ambiguity is aversive, impacting choice behavior and reducing subjective value. • Time-ambiguity shows a neurobehavioral signature distinct from that of impatience. • Time-ambiguity is associated with increased IPS and decreased vmPFC activation. • Individual time-ambiguity preferences appear to modulate dlPFC and insula activity. [ABSTRACT FROM AUTHOR]

Homophones pose serious issues for automatic speech recognition (ASR) as they have the same pronunciation but different meanings or spellings. Homophone disambiguation is usually done within a stochastic language model or by an analysis of the homophonous word’s context, similarly to word sense disambiguation. Whereas this method reaches good results in read speech, it fails in conversational, spontaneous speech, where utterances are often short, contain disfluencies and/or are realized syntactically incomplete. Phonetic studies, however, have shown that words that are homophonous in read speech often differ in their phonetic detail in spontaneous speech. Whereas humans use phonetic detail to disambiguate homophones, this linguistic information is usually not explicitly incorporated into ASR systems. In this paper, we show that phonetic detail can be used to automatically disambiguate homophones using the example of German pronouns. Using 3179 homophonous tokens from a corpus of spontaneous German and a set of acoustic features, we trained a random forest model. Our results show that homophones can be disambiguated reasonably well using acoustic features (74% F 1 , 92% accuracy). In particular, this model is able to outperform a model based on lexical context (48% F 1 , 89% accuracy). This paper is of relevance for speech technologists and linguists: amodule using phonetic detail similar to the presented model is suitable to be integrated in ASR systems in order to improve recognition. An approach similar to the work here that combines the automatic extraction of acoustic features with statistical analysis is suitable to be integrated in phonetic analysis aiming at finding out more about the contribution and interplay of acoustic features for functional categories. [ABSTRACT FROM AUTHOR]

Abstract I consider static, incomplete information games where players may not be ambiguity neutral. Every player is one of a finite set of types, and each knows her own type but not that of the other players. Ex ante, players differ only in their taste for outcomes. If every player is dynamically consistent with respect to her own information structure and respects Consequentialism, then players act as if expected utility for uncertainty about types. [ABSTRACT FROM AUTHOR]

In this work, we exploit the power of finite ambiguity for the complementation problem of Büchi automata by using reduced run directed acyclic graphs (DAGs) over infinite words, in which each vertex has at most one predecessor; these reduced run DAGs have only a finite number of infinite runs, thus obtaining the finite ambiguity in Büchi complementation. We show how to use this type of reduced run DAGs as a unified tool to optimize both rank-based and slice-based complementation constructions for Büchi automata with a finite degree of ambiguity. As a result, given a Büchi automaton with n states and a finite degree of ambiguity, the number of states in the complementary Büchi automaton constructed by the classical rank-based and slice-based complementation constructions can be improved from 2 O (n log ⁡ n) and O ((3 n) n) to O (6 n) ⊆ 2 O (n) and O (4 n) , respectively. We further show how to construct such reduced run DAGs for limit deterministic Büchi automata and obtain a specialized complementation algorithm, thus demonstrating the generality of the power of finite ambiguity. [ABSTRACT FROM AUTHOR]

The paper demonstrates the non-closure of the family of unambiguous linear languages (that is, those defined by unambiguous linear context-free grammars) under complementation. To be precise, a particular unambiguous linear grammar is presented, and it is proved that the complement of this language is not defined by any context-free grammar. This also constitutes an alternative proof for the result of Hibbard and Ullian ("The independence of inherent ambiguity from complementedness among context-free languages", JACM , 1966) on the non-closure of the unambiguous languages under complementation. [ABSTRACT FROM AUTHOR]

• Patients who have gone through FLR show difficulties with decision-making under ambiguity. • They fail to learn from feedback throughout the Iowa Gambling Task. • Decision-making under ambiguity was not correlated to results in executive tasks. Decision-making is crucial to daily life and can impact our society as well as economic conditions. Although the frontal lobes have been identified as important for decision-making, this capacity has only been studied to a limited extent in frontal lobe epilepsy and not at all after frontal lobe resection (FLR) for epilepsy. This study aimed to explore decision-making under ambiguity after FLR for epilepsy. Fourteen patients having undergone FLR for epilepsy completed the Iowa Gambling Task (IGT) which is a widely used tool to measure decision-making under ambiguity. Iowa Gambling Task scores included in the analysis were: total net score, separate scores from five blocks across the test, and a change score (last block of IGT minus first block). A group of healthy controls (n = 30) was used as a comparison. Associations between IGT and standardized neuropsychological methods for assessment of executive functions, self-rating questionnaires of mental health, fatigue, and behavior linked to frontal lobe dysfunction were also investigated. The patient group performed inferior to controls at the final block of the IGT (p =.001). A group difference in IGT change scores was found (p =.005), reflecting the absence of a positive change in performance over time for the FLR group compared to the control group. Correlations with tests of executive functions as well as self-rating scales were mainly statistically nonsignificant. This study shows that patients having undergone FLR for epilepsy have difficulties with decision-making under ambiguity. The performance illustrated a failure to learn throughout the task. Executive as well as emotional deficits may impact decision-making processes in this patient group and need to be considered in further studies. Prospective studies with larger cohorts are needed. [ABSTRACT FROM AUTHOR]