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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]

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]

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]

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]

[Display omitted] • We present the most comprehensive phylogeny for the crab superfamily Xanthoidea. • Results upend conventional morphology-based classification. • 6 xanthoidean families are recognized including revised subfamilial classification. • Diversification in xanthoid crabs is not associated with habitat depth. Maximum likelihood and Bayesian phylogenies for the brachyuran crab superfamily Xanthoidea were estimated based on three mitochondrial and four nuclear genes to infer phylogenetic relationships and inform taxonomy. Habitat data was then used in conjunction with several diversification rates analyses (BAMM, BiSSE, HiSSE, and FiSSE) to test evolutionary hypotheses regarding the diversification of xanthoid crabs. The phylogenies presented are the most comprehensive to date in terms of global diversity as they include all four constituent families (Xanthidae, Panopeidae, Pseudorhombilidae, and Linnaeoxanthidae) spanning all oceans in which xanthoid crabs occur. Six Xanthoidea families are recognised. Panopeidae and Xanthidae sensu stricto are the two largest family-level clades, which are reciprocally monophyletic. Pseudorhombilidae is nested within and is here treated as a subfamily of Panopeidae. Former subfamilies or tribes of Xanthidae sensu lato are basally positioned clades in Xanthoidea and are here assigned family-level ranks: Garthiellidae, Linnaeoxanthidae, Antrocarcinidae, and Nanocassiopidae. The genera Linnaeoxantho and Melybia were recovered in separate clades with Linnaeoxantho being sister to the family Antrocarcinidae, while Melybia was recovered within the family Panopeidae. The existing subfamily classification of Xanthidae and Panopeidae is drastically restructured with 20 xanthid and four panopeid subfamilies provisionally recognised. Diversification-time analyses inferred the origin of Xanthoidea and Garthiellidae in the Eocene, while the other families originated during the Oligocene. The majority of genus- and species-level diversification took place during the Miocene. Ancestral state reconstruction based on depth of occurrence (shallow vs. deep water) shows some ambiguity for the most recent common ancestor of Xanthoidea and Nanocassiopidae. The most recent common ancestors of Antrocarcinidae and Panopeidae were likely deep-water species, while those of Garthiellidae and Xanthidae were probably shallow-water species. Several shifts in net diversification rates were detected but they were not associated with depth-related habitat transitions. [ABSTRACT FROM AUTHOR]

A morphism g is ambiguous with respect to a word u if there exists a second morphism h ≠ g such that g (u) = h (u). Otherwise g is unambiguous with respect to u. Thus unambiguous morphisms are those for which the structure of the morphism is preserved in the image. Ambiguity has so far been studied for morphisms of free monoids, where several characterisations exist for the set of words u permitting an (injective) unambiguous morphism. In the present paper, we consider ambiguity of morphisms of free groups, and consider possible analogies to the existing characterisations in the free monoid. While a direct generalisation results in a trivial situation where all morphisms are ambiguous, we discuss some natural and well-motivated reformulations, and provide a characterisation of words in a free group that permit a morphism which is "as unambiguous as possible". [ABSTRACT FROM AUTHOR]

Social group identity plays a central role in political polarization and inter-party conflict. Here, we use ambiguously valenced faces to measure bias in the processing of political ingroup and outgroup faces, while also accounting for inter-party differences in judgments of emotion at baseline. Participants identifying as Democrats and Republicans judged happy, angry, and surprised faces as positive or negative. Whereas happy and angry faces convey positive and negative valence respectively, surprised faces are ambiguous in that they readily convey positive and negative valence. Thus, surprise is a useful tool for characterizing valence bias (i.e., the tendency to judge ambiguous stimuli as negative). Face stimuli were assigned to the participants' political ingroup or outgroup, or a third group with an unspecified affiliation (baseline). We found a significant interaction of facial expression and group membership, such that outgroup faces were judged more negatively than ingroup and baseline, but only for surprise. There was also an interaction of facial expression and political affiliation, with Republicans judging surprise more negatively than Democrats across all group conditions. However, we did not find evidence for party differences in outgroup negativity. Our findings demonstrate the utility of judgments of surprised faces as a measure of intergroup bias, and reinforce the importance of outgroup negativity (relative to ingroup positivity) for explaining inter-party biases. • Republicans and Democrats viewed emotional faces of ingroup and outgroup members. • Emotional ambiguity was associated with a bias towards outgroup negativity. • There was no evidence of ingroup positivity. • Parties differed in their overall tendency to judge surprise as negative (R > D). [ABSTRACT FROM AUTHOR]

We argue that different formulations of hydrodynamics are related to uncertainties in the definitions of local thermodynamic and hydrodynamic variables. We show that this ambiguity can be resolved by viewing different formulations of hydrodynamics as particular "gauge choices" which lead to the same physical behavior of the system. Using the example of bulk viscosity, we show that Bemfica–Disconzi–Noronha–Kovtun (BDNK) and Israel–Stewart hydrodynamics are particular "gauge choices" of this type, related by a well-defined transformation of thermodynamic and hydrodynamic variables. We argue that this gauge ambiguity is necessary to ascertain the causality of stochastic hydrodynamic evolution and conjecture that it could explain the applicability of hydrodynamics outside its expected regime of validity since far from equilibrium and close to equilibrium may be related through transformations of this type. The paper discusses the role of microscopic statistical mechanics within hydrodynamics with arbitrary frame redefinition. [ABSTRACT FROM AUTHOR]

Our research centers the underexamined perspective of Black Americans regarding allyship behaviors and investigates their perceptions and experience of a White ally who confronts a White perpetrator of prejudice. In two experimental studies (N = 1176), we found that Black participants reported higher levels of self-esteem after a White ally confronted a White perpetrator of racial prejudice compared to no confrontation. Additionally, we found that White ally confrontations that signaled intrinsic motivations (i.e., driven by personal values) were perceived as less suspicious in motive than those that signaled extrinsic motivations (i.e., driven by image concerns), which related to more target self-esteem. We discuss implications for research on allyship and confrontation as well as practical considerations. Our results strongly suggest that advantaged group members cannot allow overt prejudice to stand unchecked and should consider the motivations they convey in their actions. [ABSTRACT FROM AUTHOR]

Cross-situational statistical word learning (CSWL) refers to the process whereby participants learn new words by tracking ambiguous word-object co-occurrences across time. This study used event-related potentials to explore the acquisition of novel word meanings via CSWL in healthy adults. After learning to associate novel auditory words (e.g., 'ket') with familiar objects (e.g., sword), participants performed a semantic judgement task where the learned novel words were paired with a familiar word belonging to either the same (e.g., dagger) or a different (e.g., harp) semantic category. As a comparison, the task also included word pairs comprising two familiar words. The analyses revealed that the unrelated novel word pairs elicited a similar N400 to that of the unrelated familiar word pairs, but with a different hemispheric distribution (left hemisphere for novel words, right hemisphere for familiar words). These findings demonstrate rapid meaning acquisition via CSWL, which is reflected at a neurophysiological level. [ABSTRACT FROM AUTHOR]

Studies on decision-making under uncertainty have mainly focused on understanding preferences for either risk or ambiguity using standard lottery designs. However, people often face uncertainty that directly stems from interacting with other people, which may be processed differently from lottery-based uncertainty. Here, we substantially extend the investigation of uncertainty by examining a fourfold pattern of the sources and the types of uncertainty, assessing behavioral and neural responses to both risk and ambiguity across both social and non-social contexts. A key element in our research design was to control for participants' naturally occurring social beliefs, and taking these a priori beliefs into account allow us to elicit individual preferences in accordance with economic approaches that stress the dynamics of ambiguity preference as a function of underlying likelihoods. Using this design, we find a behavioral main effect of ambiguity aversion, with increasing ambiguity aversion as a function of higher beliefs regarding the likelihood of reciprocity, and related neural activity in the right IPS. This brain region was primarily involved when participants experienced lottery-based uncertainty as opposed to social uncertainty. However, we found that the right IFG was more involved when participants made decisions under social, as compared to non-social, uncertainty. Overall, therefore, the IPS may activate an analytic mindset, which might resonate more with a lottery than a social context, whereas the IFG is engaged when the context requires players to resolve uncertainty, such as unraveling the intentions behind the choice of another person. [ABSTRACT FROM AUTHOR]

• Patients with TLE and patients with FLE had worse decision-making ability in uncertain situations than healthy controls. • Patients with TLE and patients with FLE had worse results in neuropsychological assessment tests in terms of attention, language functions, memory and learning, frontal axis functions, and visuospatial functions compared with healthy subjects. • A negative correlation was found between impulsivity and decision-making performance in patients with FLE. • Decision-making performance worsened as sleepiness scores increased in patients with TLE. The effect of the frontal lobe on cognitive functions is a subject that has been studied frequently. However, cognitive impairments that can be seen in frontal lobe epilepsy are less addressed. In previous studies on decision-making disorders in patients with epilepsy, patients with temporal lobe epilepsy (TLE) were frequently studied, and it was reported that decision-making disorders could be encountered in this patient group. In this study, we aimed to compare the decision-making performance of patients with cryptogenic frontal lobe epilepsy (FLE) and TLE in ambiguous situations. Twenty patients with TLE (mean age: 34.10 ± 11.71 years) and 20 patients with FLE (mean age: 32.25 ± 11.92 years) were enrolled in the study and their cognitive performance was compared with 20 healthy controls (mean age: 33.15 ± 13.66 years). Neuropsychological tests were performed on the participants for sleep, depression, anxiety, impulsivity, intelligence, attention, language functions, memory and learning, and frontal axis functions. Decision-making performance in ambiguous situations was studied using the Iowa Gambling Task (IGT). Iowa Gambling Task performances of patients with FLE and TLE were found to be worse than in healthy controls (p = 0.049). Although there was no statistically significant difference when the decision-making of patients with TLE and FLE was compared, it was observed that patients with FLE chose higher risk cards compared with those with TLE. The performances of the neuropsychological subgroup tests of patients with TLE and FLE in attention, language functions, memory and learning, and frontal axis functions were found to be significantly worse than in healthy subjects. Decision-making in patients with TLE and FLE in ambiguous situations is similarly impaired compared with healthy controls. [ABSTRACT FROM AUTHOR]

• The blade resonance models under excitation sources are established. • A method of identifying excitation sources from blade vibration phase is proposed. • An unwrapping method addressing phase ambiguity is proposed. • The identification error of excitation source's position is less than ±1°. Wake excitation is the main cause of synchronous vibration of large rotating machines' blades, whose circumferential position reflects the distortion position of flow field. However, little research has been published concerning the identification of excitation source's circumferential position based on blade vibration parameters. A new identification method using vibration phase is proposed in this paper. The excitation force model is established along with the forced vibration response model of blades under excitation sources. A phase unwrapping method is proposed to solve phase ambiguity, and the excitation source's circumferential position is achieved through vibration phase and engine orders of the same rotating blade in adjacent resonance regions. Experimental results verified the effectiveness and accuracy of the proposed method. The identification error of excitation source's circumferential position is less than ±1°. [ABSTRACT FROM AUTHOR]

• Repeated letters make strings perceptually more ambiguous. • Strings with unique letters are more easily processed accurately. • These results held across masked-priming and perceptual identification tasks. • Modelling results are presented from LTRS and Overlap models. Letters are often repeated in words in many languages. The present work explored the mechanisms underlying processing of repeated and unique letters in strings across three experimental paradigms. In a 2AFC perceptual identification task, the insertion but not the deletion of a letter was harder to detect when it was repeated than when it was unique (Exp. 1). In a masked primed same-different task, deletion primes produced the same priming effect regardless of deletion type (repeated, unique; Exp. 2), but insertion primes were more effective when the additional inserted letter created a repetition than when it did not (Exp. 3). In a same-different perceptual identification task, foils created by modifying a repetition, by either repeating the wrong letter or substituting a repeated letter, were harder to reject than foils created by modifying unique letters (Exp. 4). Thus, repetition effects were task-dependent. Since considering representations alone would suggest repetition effects would always occur or never occur, this indicates the importance of modelling task-specific processes. The similarity calculations embedded in the Overlap Model (Gomez et al., 2008) appeared to always predict a repetition effect, but its decision rule for the task of Experiment 1 allowed it to predict the asymmetry between insertions and deletions. In the Letters in Time and Retinotopic Space (LTRS; Adelman, 2011) model, repetition effects arise only from briefly presented stimuli as their perception is incomplete. It was therefore consistent with Experiments 2–4 but required a task-specific response bias to account for the insertion-deletion asymmetry of Experiment 1. [ABSTRACT FROM AUTHOR]

Probabilistic automata are an extension of nondeterministic finite automata in which transitions are annotated with probabilities. Despite its simplicity, this model is very expressive and many algorithmic questions are undecidable. In this work we focus on the emptiness problem (and its variant the value problem), which asks whether a given probabilistic automaton accepts some word with probability greater than a given threshold. We consider finitely ambiguous probabilistic automata. Our main contributions are to construct efficient algorithms for analysing finitely ambiguous probabilistic automata through a reduction to a multi-objective optimisation problem called the stochastic path problem. We obtain a polynomial time algorithm for approximating the value of probabilistic automata of fixed ambiguity and a quasi-polynomial time algorithm for the emptiness problem for 2-ambiguous probabilistic automata. We complement these positive results by an inapproximability result stating that the value of finitely ambiguous probabilistic automata cannot be approximated unless P = NP. [ABSTRACT FROM AUTHOR]

An automaton is unambiguous if for every input it has at most one accepting computation. An automaton is finitely (respectively, countably) ambiguous if for every input it has at most finitely (respectively, countably) many accepting computations. An automaton is boundedly ambiguous if there is k ∈ N , such that for every input it has at most k accepting computations. We consider nondeterministic Büchi automata (NBA) over infinite trees and prove that it is decidable in polynomial time, whether an automaton is unambiguous, boundedly ambiguous, finitely ambiguous, or countably ambiguous. [ABSTRACT FROM AUTHOR]

• We manipulated lexical cues and the plausibility of structurally ambiguous sentences. • 5-year olds rapidly used lexical cues to resolve ambiguity during comprehension. • 5-year olds made little use of plausibility to resolve ambiguity. • During comprehension, adults relied almost exclusively on plausibility. Both 5-year-old children and adults infer the structure of a sentence as they are hearing it. Prior work, however, has found that children do not always make use of the same information that adults do to guide these inferences. Specifically, when hearing ambiguous sentences like "You can tickle the frog with the feather," children seem to ignore the aspects of the referential context that adults rely on to resolve the ambiguity—e.g., are there two frogs in the scene, one with a feather and one without? Or is there only one frog to be tickled by using a feather? The present study explored two hypotheses about children's failure to use high-level, top-down context cues to infer the structure of these ambiguous sentences: First, children may be less likely to use any top-down cue during comprehension. Second, children may only have difficulties with top-down cues that are unreliable predictors of which syntactic structure is being used. Thus, to disentangle these hypotheses, we conducted a visual world study of adults' and children's ambiguity resolution, manipulating a more reliable top-down cue (the plausibility of the interpretation) and pitting it against a robust bottom-up cue (lexical biases). We find that adults' and children's final interpretations are influenced by both sources of information: adults, however, give greater weight to the top-down cue, whereas children primarily rely on the bottom-up cue. Thus, children's tendency to make minimal use of top-down information persists even when this information is highly valid and dominates adult comprehension. We propose that children have a systematic propensity to rely on bottom-up processing to a greater degree than adults, which could reflect differences in the architecture of the adult and child language comprehension systems or differences in processing speed. [ABSTRACT FROM AUTHOR]

• Risk-taking is a multifactorial construct that can be dissociated into economic risk and economic ambiguity, each supported by distinct neural mechanisms. • How ambiguity aversion develops over adolescence remains largely unknown. • Ambiguity aversion and risk aversion relate to everyday risk-taking in different ways. • We propose a renewed focus on ambiguity in research on adolescent risk-taking. Popular culture often portrays adolescence as a period of peak risk-taking, but that developmental trend is not consistently found across laboratory studies. Instead, meta -analytic evidence shows that while adolescents take more risks compared to adults, children and adolescents actually take similar levels of risk. Furthermore, developmental trajectories vary across different measures of laboratory decision making and everyday risky behavior. Indeed, the psychological concept of "risk" is multifactorial, such that its different factors exhibit different developmental trajectories. Here, we examine how economic risk preference, or the propensity to gamble on uncertain outcomes with known probabilities, is distinct from economic ambiguity preference, or the propensity to gamble on uncertain outcomes with unknown probabilities -- and how economic risk and ambiguity may differentially influence adolescent decision making. Economic ambiguity engages distinct neural mechanisms from economic risk – both in adults and adolescents – and differentially relates to everyday risk-taking. However, to date, it remains elusive how economic ambiguity aversion develops across adolescence, as the relative paucity of such work limits the conclusions that can be drawn. We propose that developmental research into adolescent decision making should consider economic ambiguity as a distinct component within the multifactorial construct of adolescent risk-taking. This will set the stage for future work on economic ambiguity preferences as an explanatory mechanism for behaviors beyond risk taking, such as learning and prosocial behavior. [ABSTRACT FROM AUTHOR]

Risk and ambiguity are inherent in virtually all human decision-making. Risk refers to a situation in which we know the precise probability of potential outcomes of each option, whereas ambiguity refers to a situation in which outcome probabilities are not known. A large body of research has shown that individuals prefer known risks to ambiguity, a phenomenon known as ambiguity aversion. One heated debate concerns whether risky and ambiguous decisions rely on the same or distinct neural circuits. In the current meta-analyses, we integrated the results of neuroimaging research on decision-making under risk (n = 69) and ambiguity (n = 31). Our results showed that both processing of risk and ambiguity showed convergence in anterior insula, indicating a key role of anterior insula in encoding uncertainty. Risk additionally engaged dorsomedial prefrontal cortex (dmPFC) and ventral striatum, whereas ambiguity specifically recruited the dorsolateral prefrontal cortex (dlPFC), inferior parietal lobe (IPL) and right anterior insula. Our findings demonstrate overlapping and distinct neural substrates underlying different types of uncertainty, guiding future neuroimaging research on risk-taking and ambiguity aversion. [ABSTRACT FROM AUTHOR]