8,476 research outputs found

    Value certainty and choice confidence are multidimensional constructs that guide decision-making

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    The degree of certainty that decision-makers have about their evaluations of available choice alternatives and their confidence about selecting the subjectively best alternative are important factors that affect current and future value-based choices. Assessments of the alternatives in a given choice set are rarely unidimensional; their values are usually derived from a combination of multiple distinct attributes. For example, the taste, texture, quantity, and nutritional content of a snack food may all be considered when determining whether to consume it. We examined how certainty about the levels of individual attributes of an option relates to certainty about the overall value of that option as a whole and/or to confidence in having chosen the subjectively best available option. We found that certainty and confidence are derived from unequally weighted combinations of attribute certainties rather than simple, equal combinations of all sources of uncertainty. Attributes that matter more in determining choice outcomes also are weighted more in metacognitive evaluations of certainty or confidence. Moreover, we found that the process of deciding between two alternatives leads to refinements in both attribute estimations and the degree of certainty in those estimates. Attributes that are more important in determining choice outcomes are refined more during the decision process in terms of both estimates and certainty. Although certainty and confidence are typically treated as unidimensional, our results indicate that they, like value estimates, are subjective, multidimensional constructs

    Computerized Response Inhibition Training For Children With Trichotillomania

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    Evidence suggests that trichotillomania is characterized by impairment in response inhibition, which is the ability to suppress pre-potent/dominant but inappropriate responses. This study sought to test the feasibility of computerized response inhibition training for children with trichotillomania. Twenty-two children were randomized to the 8-session response inhibition training (RIT; n = 12) or a waitlisted control (WLT; n = 10). Primary outcomes were assessed by an independent evaluator, using the Clinical Global Impression-Improvement (CGI-I), and the NIMH Trichotillomania Severity (NIMH-TSS) and Impairment scales (NIMH-TIS) at pre, post-training/waiting, and 1-month follow-up. Relative to the WLT group, the RIT group showed a higher response rate (55% vs. 11%) on the CGI-I and a lower level of impairment on the NIMH-TIS, at post-training. Overall symptom reductions rates on the NIMH-TSS were 34% (RIT) vs. 21% (WLT) at post-training. The RIT\u27s therapeutic gains were maintained at 1-month follow-up, as indicated by the CGI-I responder status (= 66%), and a continuing reduction in symptom on the NIMH-TSS. This pattern of findings was also replicated by the 6 waitlisted children who received the same RIT intervention after post-waiting assessment. Results suggest that computerized RIT may be a potentially useful intervention for trichotillomania

    Evidence or Confidence: What Is Really Monitored during a Decision?

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    Assessing our confidence in the choices we make is important to making adaptive decisions, and it is thus no surprise that we excel in this ability. However, standard models of decision-making, such as the drift-diffusion model (DDM), treat confidence assessment as a post hoc or parallel process that does not directly influence the choice, which depends only on accumulated evidence. Here, we pursue the alternative hypothesis that what is monitored during a decision is an evolving sense of confidence (that the to-be-selected option is the best) rather than raw evidence. Monitoring confidence has the appealing consequence that the decision threshold corresponds to a desired level of confidence for the choice, and that confidence improvements can be traded off against the resources required to secure them. We show that most previous findings on perceptual and value-based decisions traditionally interpreted from an evidence-accumulation perspective can be explained more parsimoniously from our novel confidence-driven perspective. Furthermore, we show that our novel confidence-driven DDM (cDDM) naturally generalizes to decisions involving any number of alternative options – which is notoriously not the case with traditional DDM or related models. Finally, we discuss future empirical evidence that could be useful in adjudicating between these alternatives

    Assessment of Natural Stream Sites for Hydroelectric Dams in the Pacific Northwest Region

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    This pilot study presents a methodology for modeling project characteristics using a development model of a stream obstructing dam. The model is applied to all individual stream reaches in hydrologic region 17, which encompasses nearly all of Idaho, Oregon, and Washington. Project site characteristics produced by the modeling technique include: capacity potential, principal dam dimensions, number of required auxiliary dams, total extent of the constructed impoundment boundary, and the surface area of the resulting reservoir. Aggregated capacity potential values for the region are presented in capacity categories including total, that at existing dams, within federal and environmentally sensitive exclusion zones, and the balance which is consider available for greenfield development within the limits of the study. Distributions of site characteristics for small hydropower sites are presented and discussed. These sites are screened to identify candidate small hydropower sites and distributions of the site characteristics of this site population are presented and discussed. Recommendations are made for upgrading the methodology and extensions to make the results more accessible and available on a larger scale

    Elephants can determine ethnicity, gender, and age from acoustic cues in human voices

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    Animals can accrue direct fitness benefits by accurately classifying predatory threat according to the species of predator and the magnitude of risk associated with an encounter. Human predators present a particularly interesting cognitive challenge, as it is typically the case that different human subgroups pose radically different levels of danger to animals living around them. Although a number of prey species have proved able to discriminate between certain human categories on the basis of visual and olfactory cues, vocalizations potentially provide a much richer source of information. We now use controlled playback experiments to investigate whether family groups of free-ranging African elephants (Loxodonta africana) in Amboseli National Park, Kenya can use acoustic characteristics of speech to make functionally relevant distinctions between human subcategories differing not only in ethnicity but also in sex and age. Our results demonstrate that elephants can reliably discriminate between two different ethnic groups that differ in the level of threat they represent, significantly increasing their probability of defensive bunching and investigative smelling following playbacks of Maasai voices. Moreover, these responses were specific to the sex and age of Maasai presented, with the voices of Maasai women and boys, subcategories that would generally pose little threat, significantly less likely to produce these behavioral responses. Considering the long history and often pervasive predatory threat associated with humans across the globe, it is likely that abilities to precisely identify dangerous subcategories of humans on the basis of subtle voice characteristics could have been selected for in other cognitively advanced animal species

    The role of palliative radiotherapy for haemostasis in unresectable gastric cancer:a single-institution experience

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    Purpose: To evaluate the outcomes of patients with gastric cancer bleeding who had been treated with palliative radiotherapy with haemostatic intent. Methods and materials: Fifty-two gastric cancer patients aged 52–92 years (median 78 years) with active bleeding or anaemia resulting from inoperable gastric cancer were treated with short-course radiotherapy. Responses to radiotherapy treatment were evaluated based on the changes of haemoglobin level, number of transfusions received before and after radiotherapy, and overall median survival. Results: Thirty-nine (75%) patients received single 8 Gy fraction, and 13 (25%) patients received 20 Gy in five daily fractions. The need for transfusion was evaluable in 44 patients, and the response rate was 50%, with less requirement for blood transfusions within four weeks of radiotherapy. There was also an increase in mean haemoglobin level (0.66 ± 1.12 g/dl, p < 0.01) after radiotherapy in 35 evaluable patients. The overall median survival (calculated from last day of treatment to date of death) was 160 days (95% CI of 119–201 days), making actuarial 12-month survival 15%. Conclusion: Palliative short-course radiotherapy is a reasonably effective treatment that can provide durable palliation of bleeding in gastric cancer. Keywords: bleeding, gastric cancer, haemostasis, palliative, radiotherap

    Polar Bear Conservation in Canada: Defining the Policy Problems

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    Conservation of polar bears (Ursus maritimus) in Canada is based on the goals and principles of the 1973 International Agreement on the Conservation of Polar Bears and Their Habitat, and has long been considered an exemplar of science-based wildlife management. However, accelerating social and ecological changes in the Arctic raise questions about the polar bear management regime’s ability to adapt successfully to new challenges. We apply the analytic framework of the policy sciences to develop a comprehensive orientation to this evolving situation, and we suggest possible ways to define and advance shared goals of stakeholders and other participants. We conclude that the decision process in polar bear management does not sufficiently foster identification and securing of common interests among participants who express multiple, competing perspectives in an arena that has been increasingly fragmented and symbolically charged by issues such as the recent listing of polar bears under the U.S. Endangered Species Act. The fundamental challenge for polar bear conservation in Canada is to design a better decision process so that it can constructively reconcile the various perspectives, demands, and expectations of stakeholders.Au Canada, la conservation des ours polaires (Ursus maritimus) respecte les objectifs et les principes de l’Accord international sur la conservation des ours blancs et leur habitat de 1973, qui est considéré depuis longtemps comme un modèle de gestion de la faune fondée sur la science. Cependant, l’évolution de plus en plus rapide des changements d’ordre social et écologique dans l’Arctique a pour effet de soulever des questions sur l’aptitude du régime de gestion de l’ours polaire à bien s’adapter aux nouveaux défis. Nous utilisons le cadre de référence analytique de la science des politiques pour aboutir à une orientation exhaustive de cette situation en pleine évolution, et nous suggérons des manières possibles de définir et de formuler des objectifs partagés par les parties prenantes et d’autres participants. Nous concluons que le processus de décision en matière de gestion de l’ours polaire n’encourage pas suffisamment l’identification et l’engagement d’intérêts communs entre les participants qui expriment des perspectives multiples et concurrentes dans un domaine de plus en plus fragmenté et symboliquement caractérisé par des enjeux tels que la liste récente d’ours polaires en vertu de la loi américaine sur les espèces en voie de disparition (U.S. Endangered Species Act). Le défi fondamental en ce qui a trait à la conservation des ours polaires au Canada consiste à concevoir un meilleur processus de décision pouvant réconcilier, de manière constructive, les diverses perspectives, exigences et attentes des parties prenantes

    Lower Levels of Glutathione (GSH) in the Brains of Secondary Progressive Multiple Sclerosis Patients Measured by 1H Magnetic Resonance Chemical Shift Imaging at 3 T

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    BACKGROUND: Disability levels for patients with secondary progressive multiple sclerosis (SPMS) often worsen despite a stable MRI T2 lesion burden. The presence of oxidative stress in the absence of measurable inflammation could help explain this phenomenon. In this study, the assessment of an in vivo marker of oxidative stress, cerebral glutathione (GSH), using magnetic resonance chemical shift imaging (CSI) is described, and GSH levels were compared in patients with SPMS and healthy controls. OBJECTIVE: To assess whether GSH, a key antioxidant in the brain, is lower in the SPMS patients compared to matched controls. METHODS: Seventeen patients with SPMS (Expanded Disability Status Scale = 4.0–7.0; length of MS diagnosis = 19.4±7 years) and 17 age- and gender-matched healthy controls were studied. GSH levels were measured in the fronto-parietal regions of the brain using a specially designed magnetic resonance spectroscopy technique, CSI of GSH, at 3T. RESULTS: The levels of GSH were lower for SPMS patients than for controls, the largest reduction (18.5%) being in the frontal region (p=0.001). CONCLUSION: The lower GSH levels in these patients indicate the presence of oxidative stress in SPMS. This process could be at least partially responsible for ongoing functional decline in SPMS

    The Role of the IMF in Future Sovereign Debt Restructurings: Report of the Annenberg House Expert Group

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    A meeting of international finance and insolvency experts was held on November 2, 2013 at the Annenberg House in Santa Monica, California. The meeting was co-hosted by the USC Law School and the Annenberg Retreat at Sunnylands. The goal was to solicit the views of experts on the implications of the IMF’s April 26, 2013 paper captioned “Sovereign Debt Restructuring -- Recent Developments and Implications for the Fund’s Legal and Policy Framework”. The April 26 paper may signal a shift in IMF policies in the area of sovereign debt workouts. Although the Expert Group discussed a number of the ideas contained in the April 26 paper, attention focused on paragraph 32 of that paper. That paragraph states in relevant part: “There may be a case for exploring additional ways to limit the risk that Fund resources will simply be used to bail out private creditors. For example, a presumption could be established that some form of a creditor bail-in measure would be implemented as a condition for Fund lending in cases where, although no clear-cut determination has been made that the debt is unsustainable, the member has lost market access and prospects for regaining market access are uncertain.” This Report summarizes the consensus views of the Expert Group on the practical implications of the suggestions contained in paragraph 32 of the April 26 paper
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