The Relationship Between Anxiety And Risk Taking Is Moderated By Ambiguity

By definition, risk taking involves uncertainty surrounding potential outcomes. However, risky decisions can vary in the amount of ambiguity about the likelihood of each outcome occurring. The current study tested the hypothesis that the amount of ambiguity in risky-decisions would moderate the relationship between risk taking and anxiety. In this study, participants completed individual difference measures and then a version of the Balloon Analogue Risk Task (BART) with either high or low ambiguity about the likelihood of a negative outcome. As hypothesized, higher levels of anxiety predicted less risk taking in the high ambiguity version of the BART, but anxiety and risk taking were unrelated to one another in the low ambiguity version. This study demonstrates that in order to understand the relationship between anxiety and risk taking, ambiguity level must be taken into account. Furthermore, this finding provides support for cognitive models of anxiety suggesting that anxious individuals interpret negative outcomes as more likely to occur than less anxious individuals

Adaptation of Upper Airway Muscles to Chronic Endurance Exercise

We tested the hypothesis that chronic endurance exercise is associated with the recruitment of four major upper airway muscles (genioglossus, digastric, sternohyoid, and omohyoid) and results in an increased oxidative capacity and a fast-toward-slow shift in myosin heavy chain (MHC) isoforms of these muscles. Female Sprague–Dawley rats (n = 8; 60 days old) performed treadmill ex- ercises for 12 weeks (4 days/week; 90 minutes/day). Age-matched sedentary female rats (n = 10) served as control animals. Training was associated with an increase (p 0.05) MHC phenotype, oxidative capac- ity, or antioxidant enzyme activity in the omohyoid or genioglossus muscle. These data indicate that endurance exercise training is associated with a fast-to-slow shift in MHC phenotype together with an increase in both oxidative and antioxidant capacity in se- lected upper airway muscles. It seems possible that this exercise- mediated adaptation is related to the recruitment of these mus- cles as stabilizers of the upper airway

Resisting Anchoring Effects: The Roles Of Metric And Mapping Knowledge

The biasing influence of anchors on numerical estimates is well established, but the relationshipbetween knowledge level and the susceptibility to anchoring effects is less clear. In two studies,we addressed the potential mitigating effects of having knowledge in a domain on vulnerability toanchoring effects in that domain. Of critical interest was a distinction between two forms ofknowledge—metric and mapping knowledge. In Study 1, participants who had studiedquestion-relevant information—that is, high-knowledge participants—were less influenced byanchors than were participants who had studied irrelevant information. The results fromknowledge measures suggested that the reduction in anchoring was tied to increases in metricrather than mapping knowledge. In Study 2, participants studied information specificallydesigned to influence different types of knowledge. As we predicted, increases in metricknowledge—and not mapping knowledge—led to reduced anchoring effects. Implicationsfor debiasing anchoring effects are discusse

Sample Size Bias In Judgments Of Perceptual Averages

Previous research has shown that people exhibit a sample size bias when judging the average of a set of stimuli on a single dimension. The more stimuli there are in the set, the greater people judge the average to be. This effect has been demonstrated reliably for judgments of the average likelihood that groups of people will experience negative, positive, and neutral events (Price, 2001; Price, Smith, & Lench, 2006)and also for estimates of the mean of sets of numbers (Smith & Price, 2010). The present research focuses on whether this effect is observed for judgments of average on a perceptual dimension. In 5 experiments we show that people’s judgments of the average size of the squares in a set increase as the number of squares in the set increases. This effect occurs regardless of whether the squares in each set are presentedsimultaneously or sequentially; whether the squares in each set are different sizes or all the same size; and whether the response is a rating of size, an estimate of area, or a comparative judgment. These results are consistent with a priming account of the sample size bias, in which the sample size activates arepresentation of magnitude that directly biases the judgment of average

Trolox Attenuates Mechanical Ventilation–induced Diaphragmatic Dysfunction and Proteolysis

Prolonged mechanical ventilation results in diaphragmatic oxida-tive injury, elevated proteolysis, fiber atrophy, and reduced force-generating capacity. We tested the hypothesis that antioxidant infusion during mechanical ventilation would function as an antioxi-dant to maintain redox balance within diaphragm muscle fibers and therefore prevent oxidative stress and subsequent proteolysis and contractile dysfunction. Sprague-Dawley rats were anesthe-tized, tracheostomized, and mechanically ventilated with 21% O2 for 12 hours. The antioxidant Trolox was intravenously infused in a subset of ventilated animals. Compared with acutely anesthetized, nonventilated control animals, mechanical ventilation resulted in a significant reduction (–17%) in diaphragmatic maximal tetanic force. Importantly, Trolox completely attenuated this mechanical ventilation-induced diaphragmatic contractile deficit. Total dia-phragmatic proteolysis was increased 105% in mechanical ventila-tion animals compared with controls. In contrast, diaphragmatic proteolysis did not differ between controls and mechanical ventila-tion–Trolox animals. Moreover, 20S proteasome activity in the dia-phragm was elevated in the mechanical ventilation animals (+76%); Trolox treatment attenuated this mechanical ventilation-induced rise in protease activity. These results are consistent with the hypothesis that mechanical ventilation-induced oxidative stress is an important factor regulating mechanical ventilation-induced diaphragmatic proteolysis and contractile dysfunction. Our findings suggest that antioxidant therapy could be beneficial during pro-longed mechanical ventilatio

Knowledge Matters: Anchoring Effects Are Moderated By Knowledge Level

Previous research into the relationship between knowledge level and anchoring effects has led to mixed conclusions. This paper presents four studies that used a diverse set of stimuli and paradigms to further investigate this relationship. In Study 1, greater knowledge was associated with smaller anchoring effects—both when knowledge was measured using subjective self-assessments and when using an objective knowledge measure. In Study 2, participants from the USA and India tended to exhibit smaller anchoring effects when answering questions about their own country as compared with questions about the other country. In Study 3, higher knowledge was associated with smaller anchoring effects when examined at an idiographic level. Finally, in Study 4, providing participants with information designed to increase their knowledge led to a decrease in anchoring effects. The consistency of the results across our four studies provides evidence that anchoring effects are moderated by knowledge level in many situations

Short-Duration Mechanical Ventilation Enhances Diaphragmatic Fatigue Resistance but Impairs Force Production

Study objectives: Mechanical ventilation (MV) is a life-support measure for patients who cannot maintain adequate alveolar ventilation. Following prolonged MV, difficulty in weaning patients from the ventilator canoccur, and it has been postulated that difficult weaning is linked to respiratory muscle dysfunction. We tested thehypothesis that 18 h of controlled MV will diminish diaphragmatic maximal tetanic specific tension (force percross-sectional area of muscle) without impairing diaphragmatic fatigue resistance.Design: To test this postulate, adult Sprague-Dawley rats were randomly classified into one of two experimentalgroups: (1) control group (n = 8), and (2) 18-h MV group (n = 6). MV-treated animals were anesthetized,tracheostomized, and received room air ventilation. Animals in the control group were acutely anesthetized butdid not receive MV. Muscle strips from the mid-costal diaphragm were removed from both experimental groups,and contractile properties were studied in vitro to determine the effects of MV on diaphragmatic endurance andmaximal force production. Diaphragmatic endurance was investigated by measuring tension development duringrepeated contractions throughout a 30-min fatigue protocol.Results: MV resulted in a reduction (p 0.05) in diaphragmatic maximal specific tension (control group, 26.8 ± 0.2Newtons/cm2 vs MV group, 21.3 ± 0.6 Newtons/cm2). Compared to the control group, diaphragms from MVtreatedanimals maintained higher (p 0.05) percentages of the initial force production throughout the fatigueprotocol. The observed improvement in fatigue resistance was associated with an increase in diaphragmaticoxidative and antioxidant capacity as evidenced by increases (p 0.05) in both citrate synthase and superoxidedismutase activities. However, by comparison to the control group, diaphragms from MV-treated animalsgenerated less (p 0.05) absolute specific force throughout the fatigue protocol.Conclusions: These data indicate that 18 h of MV enhances diaphragmatic fatigue resistance but impairsdiaphragmatic specific tension

Are People Excessive Or Judicious In Their Egocentrism? A Modeling Approach To Understanding Bias And Accuracy In People’s Optimism

People are often egocentric when judging their likelihood of success in competitions, leading to overoptimism about winning when circumstances are generally easy and to overpessimism when the circumstances are difficult. Yet, egocentrism might be grounded in a rational tendency to favor highly reliable information (about the self) more so than less reliable information (about others). A generaltheory of probability called extended support theory was used to conceptualize and assess the role of egocentrism and its consequences for the accuracy of people’s optimism in 3 competitions (Studies 1–3,respectively). Also, instructions were manipulated to test whether people who were urged to avoid egocentrism would show improved or worsened accuracy in their likelihood judgments. Egocentrism wasfound to have a potentially helpful effect on one form of accuracy, but people generally showed too much egocentrism. Debias instructions improved one form of accuracy but had no impact on another. The advantages of using the EST framework for studying optimism and other types of judgments (e.g.,comparative ability judgments) are discussed

Mechanical Ventilation–induced Diaphragmatic Atrophy Is Associated with Oxidative Injury and Increased Proteolytic Activity

Prolonged mechanical ventilation (MV) results in reduced diaphrag-matic maximal force production and diaphragmatic atrophy. To investigate the mechanisms responsible for MV-induced diaphrag-matic atrophy, we tested the hypothesis that controlled MV results in oxidation of diaphragmatic proteins and increased diaphrag-matic proteolysis due to elevated protease activity. Further, we postulated that MV would result in atrophy of all diaphragmatic muscle fiber types. Mechanically ventilated animals were anesthe-tized, tracheostomized, and ventilated with 21% O2 for 18 hours. MV resulted in a decrease (p <0.05) in diaphragmatic myofibrillar protein and the cross-sectional area of all muscle fiber types (i.e., I, IIa, IId/x, and IIb). Further, MV promoted an increase (p <.05) in diaphragmatic protein degradation along with elevated (p <0.05) calpain and 20S proteasome activity. Finally, MV was also associated with a rise (p <.05) in both protein oxidation and lipid peroxidation. These data support the hypothesis that MV is associated with atrophy of all diaphragmatic fiber types, increased diaphragmatic protease activity, and augmented diaphragmatic ox-idative stress

Hoping For More: The Influence Of Outcome Desirability On Information Seeking And Predictions About Relative Quantities

People must often engage in sequential sampling in order to make predictions about the relativequantities of two options. We investigated how directional motives influence sampling selections and resulting predictions in such cases. We used a paradigm in which participants had limited time to sample items and make predictions about which side of the screen contained more of a critical item.Sampling selections were biased by monetary desirability manipulations, and participants exhibited a desirability bias for both dichotmous and continuous predictions