Is Underconfidence Favored over Overconfidence? An Experiment on the Perception of a Biased Self-Assessment

This paper reports findings of a laboratory experiment, which explores how elfassessment regarding the own relative performance is perceived by others. In particular, I investigate whether overconfident subjects or underconfident subjects are considered as more likable by others, and who of the two is expected to achieve a higher performance in a real effort task. I observe that underconfidence beats overconfidence in both respects. Underconfident subjects are rewarded significantly more often than overconfident subjects, and are significantly more often expected to win the competitive real-effort task. It seems as if subjects being less convinced of their performance are taken as more congenial and are expected to be more ambitious to improve, whereas overconfident subjects are rather expected to rest on their high beliefs. While subjects do not anticipate the stronger performance signal of underconfidence, they anticipate its higher sympathy value. The comparison to a non-strategic setting shows that men strategically deflate their self-assessment to be rewarded by others. Women, in contrast, either do not deflate their self-assessment or do so even in non-strategic situations, a behavior that might be driven by nonmonetary image concerns of women

Do Women Have More Shame than Men? An Experiment on Self-Assessment and the Shame of Overestimating Oneself

We analyze how subjects’ self-assessment depends on whether its accuracy is observable to others. We find that women downgrade their selfassessment given observability while men do not. Women avoid the shame they may have if others observe that they overestimated themselves. Men, however, do not seem to be similarly shame-averse. This gender difference may be due to different societal expectations: While we find that men are expected to be overconfident, women are not. Shame-aversion may explain recent findings that women shy away from competition, demanding jobs and wage negotiations, as entering these situations is a statement to be confident of one’s ability

Promises and Image Concerns

According to several psychological and economic studies, non-binding communication can be an effective tool to increase trust and enhance cooperation. This paper focuses on reasons why people stick to a given promise and analyzes to what extent image concerns of being perceived as a promise breaker play a role. In a controlled laboratory experiment, we vary the ex post observability of the promising party's action in order to test for social image concerns. We observe that slightly more promises are kept if the action is revealed than if it is not, yet the difference is not significant. However, a variation in the selection of pre-defined messages across treatments delivers another interesting finding. While most of the promises are kept, statements of intent tend to be broken

Competition and Incentives

We report on two experiments that identify non-monetary incentive effects of competition. As the number of competitors increases, monetary incentives to engage in cost reduction tend to decrease. We test the hypothesis that there are non-monetary incentive effects of competition going in the opposite direction. In the experiments we change the number of competitors exogenously keeping the monetary incentives to spend effort constant. The first experiment shows that subjects spend significantly more effort in duopolistic and oligopolistic markets than in a monopoly. The second experiment focuses on social comparisons as one potential mechanism for this effect. It shows that competition turns the effort decisions of competing managers into strategic complements

Ovine Enzootic Abortion (OEA): a comparison of antibody responses in vaccinated and naturally-infected swiss sheep over a two year period

Background Prevention and control of ovine enzootic abortion (OEA) can be achieved by application of a live vaccine. In this study, five sheep flocks with different vaccination and infection status were serologically tested using a competitive enzyme-linked immunosorbent assay (cELISA) specific for Chlamydophila (Cp.) abortus over a two-year time period. Results Sheep in Flock A with recent OEA history had high antibody values after vaccination similar to Flock C with natural Cp. abortus infections. In contrast, OEA serology negative sheep (Flock E) showed individual animal-specific immunoreactions after vaccination. Antibody levels of vaccinated ewes in Flock B ranged from negative to positive two and three years after vaccination, respectively. Positive antibody values in the negative control Flock D (without OEA or vaccination) are probably due to asymptomatic intestinal infections with Cp. abortus. Excretion of the attenuated strain of Cp. abortus used in the live vaccine through the eye was not observed in vaccinated animals of Flock E. Conclusion The findings of our study indicate that, using serology, no distinction can be made between vaccinated and naturally infected sheep. As a result, confirmation of a negative OEA status in vaccinated animals by serology cannot be determined

Reference values for body composition and associations with blood pressure in Kenyan adults aged ≥50 years old

Objectives: To develop age and sex-specific centile reference curves for fat free mass (FFM) and fat mass (FM) adjusted for height in an adult Kenyan population and to investigate the association between FM, FFM and blood pressure (BP). Methods: Measures of body composition from bioimpedance analyses and BP were collected in 1,995 participants aged ≥50y in Nakuru County, Kenya. Reference curves were produced using the LMS method. Multivariable linear regression models were used to test the cross-sectional association between body composition indexes and BP. Results: The age and sex-specific reference curves for body composition (FMI and FFMI) confirm that FFMI is lower in both men and women with increasing age. FMI declines with age in women while among men the decline starts after 70 years. FFM was higher in men (47.4 ± 7.2 kg) than in women (38.8 ± 5.5 kg), while FM was lower in men (17.3 ± 8.1 kg) than in women (24.4 ± 10.2 kg). FMI, FFMI and BMI were all positively associated with systolic and diastolic BP, and after adjusting for body weight, FFMI remained positively associated with systolic BP and the FMI remained positively associated with diastolic BP. There was no evidence to suggest that FMI and FFMI were superior to measurement of BMI alone. Conclusion: These body composition reference curves provide normative data on body composition for older adults in Kenya. Further research should consider the prospective associations with health, including frailty-related outcomes

Comprehensive dissection of prevalence rates, sex differences, and blood level-dependencies of clozapine-associated adverse drug reactions

Clozapine is often underused due to concerns about adverse drug reactions (ADRs) but studies into their prevalences are inconclusive. We therefore comprehensively examined prevalences of clozapineassociated ADRs in individuals with schizophrenia and demographic and clinical factors associated with their occurrence. Data from a multi-center study (n=698 participants) were collected. The mean number of ADRs during clozapine treatment was 4.8, with 2.4% of participants reporting no ADRs. The most common ADRs were hypersalivation (74.6%), weight gain (69.3%), and increased sleep necessity (65.9%), all of which were more common in younger participants. Participants with lower BMI prior to treatment were more likely to experience significant weight gain (>10%). Constipation occurred more frequently with higher clozapine blood levels and doses. There were no differences in ADR prevalence rates between participants receiving clozapine monotherapy and polytherapy. These findings emphasize the high prevalence of clozapine-associated ADRs and highlight several demographic and clinical factors contributing to their occurrence. By understanding these factors, clinicians can better anticipate and manage clozapine-associated ADRs, leading to improved treatment outcomes and patient well-being

Reproducibility in the absence of selective reporting : An illustration from large-scale brain asymmetry research

Altres ajuts: Max Planck Society (Germany).The problem of poor reproducibility of scientific findings has received much attention over recent years, in a variety of fields including psychology and neuroscience. The problem has been partly attributed to publication bias and unwanted practices such as p-hacking. Low statistical power in individual studies is also understood to be an important factor. In a recent multisite collaborative study, we mapped brain anatomical left-right asymmetries for regional measures of surface area and cortical thickness, in 99 MRI datasets from around the world, for a total of over 17,000 participants. In the present study, we revisited these hemispheric effects from the perspective of reproducibility. Within each dataset, we considered that an effect had been reproduced when it matched the meta-analytic effect from the 98 other datasets, in terms of effect direction and significance threshold. In this sense, the results within each dataset were viewed as coming from separate studies in an "ideal publishing environment," that is, free from selective reporting and p hacking. We found an average reproducibility rate of 63.2% (SD = 22.9%, min = 22.2%, max = 97.0%). As expected, reproducibility was higher for larger effects and in larger datasets. Reproducibility was not obviously related to the age of participants, scanner field strength, FreeSurfer software version, cortical regional measurement reliability, or regional size. These findings constitute an empirical illustration of reproducibility in the absence of publication bias or p hacking, when assessing realistic biological effects in heterogeneous neuroscience data, and given typically-used sample sizes