Equality bias impairs collective decision-making across cultures

We tend to think that everyone deserves an equal say in a debate. This seemingly innocuous assumption can be damaging when we make decisions together as part of a group. To make optimal decisions, group members should weight their differing opinions according to how competent they are relative to one another; whenever they differ in competence, an equal weighting is suboptimal. Here, we asked how people deal with individual differences in competence in the context of a collective perceptual decision-making task. We developed a metric for estimating how participants weight their partner’s opinion relative to their own and compared this weighting to an optimal benchmark. Replicated across three countries (Denmark, Iran, and China), we show that participants assigned nearly equal weights to each other’s opinions regardless of true differences in their competence—even when informed by explicit feedback about their competence gap or under monetary incentives to maximize collective accuracy. This equality bias, whereby people behave as if they are as good or as bad as their partner, is particularly costly for a group when a competence gap separates its members.When it comes to making decisions together, we tend to give everyone an equal chance to voice their opinion. This is not just good manners but reflects a long-standing consensus (“two heads are better than one”; Ecclesiastes 4:9–10) on the “wisdom of the crowd” (1–3). However, a question much contested (4, 5) is, once we have heard everyone’s opinion, how should they be combined so as to make the most of them? One recent suggestion is to weight each opinion by the confidence with which it is expressed (6, 7). However, this strategy may fail dramatically (8, 9) when “the fool who thinks he is wise” is paired with “the wise who [thinks] himself to be a fool” (10). In the face of such a competence gap, knowing whose confidence to lean on is critical (11).A wealth of research suggests that people are poor judges of their own competence—not only when judged in isolation but also when judged relative to others. For example, people tend to overestimate their own performance on hard tasks; paradoxically, when given an easy task, they tend to underestimate their own performance (the hard-easy effect) (12, 13). Relatedly, when comparing themselves to others, people with low competence tend to think they are as good as everyone else, whereas people with high competence tend to think they are as bad as everyone else (the Dunning–Kruger effect) (14–16). In addition, when presented with expert advice, people tend to insist on their own opinion, even though they would have benefitted from following the advisor’s recommendation (egocentric advice discounting) (17–19). These findings and similar findings suggest that individual differences in competence may not feature saliently in social interaction. However, it remains unknown whether—and to what extent—people take into account such individual differences in collective decision-making.To address this issue, we developed a computational framework inspired by recent work on how people learn the reliability of social advice (20). We used this framework to (i) quantify how members of a group weight each other’s opinions and (ii) compare this weighting to that of an optimal model in the context of a simple perceptual task. On each trial, two participants (a dyad) viewed two brief intervals, with a target in either the first or the second one (Fig. 1A). They privately indicated which interval they thought contained the target, and how confident they felt about this decision. In the case of disagreement (i.e., they privately selected different intervals), one of the two participants (the arbitrator) was asked to make a joint decision on behalf of the dyad, having access to their own and their partner’s responses. Last, participants received feedback about the accuracy of each decision before continuing to the next trial. Previous work predicts that participants would be able to use the trial-by-trial feedback to track the probability that their own decision is correct and that of their partner (21). We hypothesized that the arbitrator would make a joint decision by scaling these probabilities (p_self, and p_other) by the expressed levels of confidence (p_self × c_self and p_other × c_other), thus making full use of the information available on a given trial, and then combining these scaled probabilities into a decision criterion (DC = p_self × c_self + p_other × c_other). In addition, to capture any bias in how the arbitrator weighted their partner’s opinion, we included a free parameter (γ) that modulated the influence of the partner in the decision process (DC = p_self × c_self + γ × p_other × c_other).Open in a separate windowFig. 1.(A) The schematic shows an example trial. Dyad members observed two consecutive intervals, with a target appearing in either the first or the second one (here indicated by the dotted outline). They then privately decided which interval they thought contained the target and indicated how confident they felt about this decision. Next, their individual decisions were shared, and in the case of disagreement (i.e., they privately selected different intervals), one of the two dyad members (the arbitrator) was randomly prompted to make a joint decision on behalf of the dyad. Feedback about the accuracy of each decision was provided at the end of the trial. (B) We assumed that each participant tracked the probability of being correct given their own decision (thought bubble on the right) and that of their partner (thought bubble on the left). See main text and Methods for details. (C) A psychometric function showing the proportion of trials in which the target was reported to be in the second interval given the contrast difference between the second and the first interval at the target location. Circles, performance of the less sensitive dyad member averaged across dyads; gray squares, performance of the more sensitive dyad member averaged across dyads; and black squares, average performance of the dyad.In four experiments, we tested whether and to what extent advice taking (γ) varied with differences in competence between dyad members. To anticipate our findings, we found that the worse members of each dyad underweighted their partner’s opinion (i.e., assigned less weight to their partner’s opinion than recommended by the optimal model), whereas the better members of each dyad overweighted their partner’s opinion (i.e., assigned more weight to their partner’s opinion than recommended by the optimal model). Remarkably, dyad members exhibited this “equality bias”—behaving as if they were as good as or as bad as their partner—even when they (i) received a running score of their own and their partner’s performance, (ii) differed dramatically in terms of their individual performance, and (iii) had a monetary incentive to assign the appropriate weight to their partner’s opinion.Recently, psychological phenomena previously believed to be universal have been shown to vary across cultures—where culture is understood as a set of behavioral practices specific to a particular population (22)—calling the generalizability of studies based on Western, Educated, Industrialized, Rich, and Democratic (WEIRD) participants into question (23, 24). To test whether the pattern of advice taking observed here was culture specific, we conducted our experiments in Denmark, China, and Iran. Broadly speaking, we take these three countries to represent Northern European (Denmark), East Asian (China), and Middle Eastern (Iran) cultures. According to the latest World Values Survey,^* 71.1% of Northern European respondents (data from Norway and Sweden) and 52.3% of Chinese respondents, but only 10.6% of Iranian respondents, favored the sentence “most people can be trusted” over “you can never be too careful when dealing with people.” Reflecting this pattern of responses, research using public goods games has shown that Danish participants contribute more than Chinese and that Chinese participants in turn contribute more than Middle Eastern (data available from Turkey, Saudi Arabia, and Oman) (25, 26). Our sample should thus be sensitive to any cultural commonalities or differences in advice taking.     

Epidemiology of occult hepatitis B infection among thalassemic, hemophilia, and hemodialysis patients

Context

Hepatitis B virus (HBV) is the most common disease commuted through blood transfusion. Occult hepatitis B infection (OBI) is a form of the disease which does not present Hepatitis B surface antigens (HBsAg) in the serum of patients; however, HBV-DNA is detectable in the serum and hepatocytes of patients. OBI is an important risk factor to induce post transfusion hepatitis (PTH), cirrhosis, hepatocellular carcinoma (HCC) and reactivation of the HBV. Recently, several reports from various regions of the world have been published regarding PTH among blood recipients as well as HCC, and cirrhosis among patients who require permanent blood transfusion, including diseases such as hemophilia, hemodialysis and thalassemia. This form of the hepatitis also creates problems for individuals that are co-infected with other viruses such as HCV and HIV. To determine the prevalence of OBI among hemophilia, hemodialysis and thalassemia patients is important because it is a high risk factor for PTH, HCC and cirrhosis therefore, its detection is a critical strategy for most health care services. This review addresses recent information regarding prevalence of OBI in relation to the mentioned diseases.

Evidence Acquisition

The data presented here was collected by searching the key words in Pubmed and Scopous databases.

Results

Our searching in the published papers revealed that OBI prevalence is frequent in patients receiving frequent blood transfusions.

Conclusions

it seems that one of the main mechanisms for OBI transmission is most likely through infected blood and its component and evaluation of the prevalence of OBI in donors and patients, especially those with hemophilia and thalassemia should be foul considered.     

Improving respiratory muscle strength and health status in burn patients: a randomized controlled trial

Quality of Life Research - Pulmonary complications are among the major disadvantages of burns. The present study aimed to determine the effect of inspiratory muscle training on respiratory muscle...     

Clinical presentation and outcome of chorioretinitis sclopetaria: A case series study

Purpose

To report the clinical presentation, treatment approach and natural course of a series of chorioretinitis sclopetaria patients.

Methods

Thirteen consecutive patients with clinical diagnosis of chorioretinitis sclopetaria were included in a case series study during 2000-2006. All patients underwent clinical examination, including the best-corrected Snellen visual acuity, slit-lamp examination, applanation tonometry, funduscopy and fundus photography.Three-port standard vitrectomy was performed in two patients due to dense vitreous haemorrhage and suspected retinal detachment in both cases. All patients were followed up at week 4, months 2 and 6 and then every 6 months.

Results

The mean age of the patients was 16 ± 6 (range: 5-27) years and 11 patients (84.6%) were male. The mean follow-up period was 37 ± 18 (range: 17-82) months.Baseline best-corrected visual acuity ranged from no light perception (NLP) to 20/1600, and final visual acuity range was from NLP to 20/1200. Only one patient developed acute retinal detachment, and the retina remained attached in others through follow-up.

Conclusion

In spite of severe retinal and choroidal injuries in chorioretinitis sclopetaria, retinal detachment does not usually occur, probably due to spontaneous retinopexy and scar formation. Whilst dealing with chorioretinitis sclopetaria, it is important to make an accurate diagnosis to prevent unwarranted surgical intervention.     

Is Interval Appendectomy Necessary for Appendicular Phlegmon? A Prospective Study

Appendectomy is accepted as the standard treatment of acute appendicitis, but in complicated cases, the treatment of choice is not straightforward. In this prospective study, we compared failure rate, complications, and recurrence rate of three different approaches to complicated appendicitis. In a 5-year prospective cohort study, patients with appendicular phlegmon were studied in three groups based on the treatment protocols. Group A included patients who underwent an appendectomy; patients of group B were treated by interval appendectomy; and in group C, conservative management was performed without interval appendectomy. Data analysis was performed using SPSS version 11.5. In total, 3896 patients with acute appendicitis were admitted, and 127 patients with complicated appendicitis were treated. Fifty-four patients were excluded from the study. Differences in age, gender, weight, and duration of symptoms were not statistically significant in the three groups. In group A (N = 23), appendectomy was impossible in 4 patients and 5 patients experienced complications. In group B (N = 24), two patients underwent exploration and appendectomy. In another two patients, a recurrent episode of acute appendicitis with mild signs and symptoms occurred after discharge from the hospital. In group C (N = 25), three patients experienced a recurrent appendicitis. Interval appendectomy is not indicated in all patients and continuous non-operative management may be appropriate in some patients. As the epidemiology of colorectal cancer and inflammatory bowel diseases is different in Iran, we recommend other researchers to perform a cost-effectiveness analysis on colon and appendicular neoplasms workup after non-operative management of complicated appendicitis.     

Clinical presentation and outcome of perforating ocular injuries due to BB guns: a case series

Purpose

To describe the clinical presentations and treatment modalities of a series of BB gun-related perforating ocular injuries.

Methods

Clinical records of all consecutive cases of perforating BB gun injuries to the globe seen between September 2004 and September 2008 were reviewed retrospectively. At the time of the trauma and after final treatment, all patients underwent a complete ocular examination, including visual acuity, applanation tonometry for intraocular pressure, slit lamp biomicroscopy, indirect ophthalmoscopy and fundus photography, if possible. In all cases, primary globe repair was performed in the first session, and then appropriate surgery took place based on the individual situation.

Results

In this study, 13 patients (11 males and 2 females) with a mean age of 20.8 years (range 9-50 years) were enrolled. The mean follow-up period was 7.2 ± 4.3 months (range 1-25 months). Initial visual acuity (VA) ranged from no-light perception (NLP) to finger counting (CF). Vitreous haemorrhage and retinal detachment were present in all involved eyes. Hyphema (30.76%), uveal and retinal prolapse (30.8%), retinal incarceration (30.8%) and retinal haemorrhage (53.8%) were other ocular findings. VA remained stable in 46.2% of the patients (6 cases). The best achieved final VA was CF at 2 m in one case after 6 months follow-up. After several surgical procedures, enucleation was necessary in only 2/13 (15.4%) cases.

Conclusion

Despite several surgical procedures which decreased the number of enucleations, BB gun-perforating ocular injuries still lead to a grim visual outcome. This implies the importance of political strategies targeting on education of parents and restriction for children to access to these guns.     

The effect of clofibrate on hyperbilirubinemia of term neonates

Clofibrate is a glucuronosyl transferase inducer that has been proposed to increase the elimination of bilirubin in neonates with hyperbilirubinemia. This study was conducted to determine the therapeutic effect of clofibrate in term neonates with non-hemolytic jaundice. This study was conducted on 52 newborns with pathologic unconjugated jaundice in Qazvin children hospital. Newborns divided randomly in two groups. Case group treated with clofibrate and intensive phototherapy, while control group treated only with intensive phototherapy. Serum bilirubin level was measured before and 6, 12, 24 and 48 hours after treatment. Results were compared and analyzed. The mean serum level of bilirubin before treatment in the case and control groups were 20.78 ± 2.38 and 20.52 ± 2.44 mg/dl, respectively (P=0.69). The mean serum level of bilirubin in 6, 12, 24 and 48 hours after treatment in the case group were 18.20 ± 2.20, 14.70 ± 2.06, 10.72 ± 2.40 and 8.90 ± 0.83 mg/dl , respectively. These values in control group were 18.26 ± 2.42, 15.36 ± 2.59, 12.29 ± 2.28 and 10.23 ± 1.50 mg/dl, respectively. There was significant difference between two groups regarding mean serum level of bilirubin 24 hours (P=0.019) and 48 hours after treatment (P=0.005). In conclusion, clofibrate was effective in reducing neonatal jaundice and its effect appeared 24 hours after treatment.     

Seminal Levels of IL-10, IL-12, and IL-17 in Men with Asymptomatic Chlamydia Infection

Chlamydia trachomatis, as an obligate intracellular parasite, usually causes asymptomatic genital tract infections in both men and women with several complications. The role of C. trachomatis infection in the secretion of a number of interleukins (ILs) from epithelial cells has been established by in vitro studies performed on various cell lines. The aim of this study was to detect the seminal levels of IL-10, IL-12, and IL-17 in men with asymptomatic chlamydia infection. Our case group study included 50 semen samples being PCR-positive for C. trachomatis from 585 semen samples and the ELISA method was applied for detection of IL-10, IL-12, and IL-17. Our results demonstrated that the semen levels of IL-10 and IL-17 were significantly increased, while IL-12 was decreased in C. trachomatis-infected patients. According to these results, it may be concluded that the increased and decreased semen levels of IL-10 and IL-12, respectively, lead to impaired immune responses against C. trachomatis. Increased semen levels of IL-17 may also be associated with the pathogenesis of C. trachomatis infection.