Juliane E. Kämmer

Social Influence and the Collective Dynamics of Opinion Formation

Social influence is the process by which individuals adapt their opinion, revise their beliefs, or change their behavior as a result of social interactions with other people. In our strongly interconnected society, social influence plays a prominent role in many self-organized phenomena such as herding in cultural markets, the spread of ideas and innovations, and the amplification of fears during epidemics. Yet, the mechanisms of opinion formation remain poorly understood, and existing physics-based models lack systematic empirical validation. Here, we report two controlled experiments showing how participants answering factual questions revise their initial judgments after being exposed to the opinion and confidence level of others. Based on the observation of 59 experimental subjects exposed to peer-opinion for 15 different items, we draw an influence map that describes the strength of peer influence during interactions. A simple process model derived from our observations demonstrates how opinions in a group of interacting people can converge or split over repeated interactions. In particular, we identify two major attractors of opinion: (i) the expert effect, induced by the presence of a highly confident individual in the group, and (ii) the majority effect, caused by the presence of a critical mass of laypeople sharing similar opinions. Additional simulations reveal the existence of a tipping point at which one attractor will dominate over the other, driving collective opinion in a given direction. These findings have implications for understanding the mechanisms of public opinion formation and managing conflicting situations in which self-confident and better informed minorities challenge the views of a large uninformed majority.

Diagnostic Performance by Medical Students Working Individually or in Teams

Diagnostic errors contribute substantially to preventable medical error.1 Cognitive error is among the leading causes and mostly results from faulty data synthesis.2 Furthermore, reflecting on their confidence does not prevent physicians from committing diagnostic errors.1 Diagnostic decisions usually are not made by individual physicians working alone. Our aim was to investigate the effect of working in pairs as opposed to alone on diagnostic performance.

Factors predicting a change in diagnosis in patients hospitalised through the emergency room: a prospective observational study

Introduction Emergency rooms (ERs) generally assign a preliminary diagnosis to patients, who are then hospitalised and may subsequently experience a change in their lead diagnosis (cDx). In ERs, the cDx rate varies from around 15% to more than 50%. Among the most frequent reasons for diagnostic errors are cognitive slips, which mostly result from faulty data synthesis. Furthermore, physicians have been repeatedly found to be poor self-assessors and to be overconfident in the quality of their diagnosis, which limits their ability to improve. Therefore, some of the clinically most relevant research questions concern how diagnostic decisions are made, what determines their quality and what can be done to improve them. Research that addresses these questions is, however, still rare. In particular, field studies that allow for generalising findings from controlled experimental settings are lacking. The ER, with its high throughput and its many simultaneous visits, is perfectly suited for the study of factors contributing to diagnostic error. With this study, we aim to identify factors that allow prediction of an ERs diagnostic performance. Knowledge of these factors as well as of their relative importance allows for the development of organisational, medical and educational strategies to improve the diagnostic performance of ERs. Methods and analysis We will conduct a field study by collecting diagnostic decision data, physician confidence and a number of influencing factors in a real-world setting to model real-world diagnostic decisions and investigate the adequacy, validity and informativeness of physician confidence in these decisions. We will specifically collect data on patient, physician and encounter factors as predictors of the dependent variables. Statistical methods will include analysis of variance and a linear mixed-effects model. Ethics and dissemination The Bern ethics committee approved the study under KEK Number 197/15. Results will be published in peer-reviewed scientific medical journals. Authorship will be determined according to ICMJE guidelines. Trial registration number The study protocol Version 1.0 from 17 May 2015 is registered in the Inselspital Research Database Information System (IRDIS) and with the IRB (‘Kantonale Ethikkomission’) Bern under KEK Number 197/15.

The Potential of Collective Intelligence in Emergency Medicine: Pooling Medical Students’ Independent Decisions Improves Diagnostic Performance

Background. Evidence suggests that pooling multiple independent diagnoses can improve diagnostic accuracy in well-defined tasks. We investigated whether this is also the case for diagnostics in emergency medicine, an ill-defined task environment where diagnostic errors are rife. Methods. A computer simulation study was conducted based on empirical data from 2 published experimental studies. In the computer experiments, 285 medical students independently diagnosed 6 simulated patients arriving at the emergency room with dyspnea. Participants’ diagnoses (n = 1,710), confidence ratings, and expertise levels were entered into a computer simulation. Virtual groups of different sizes were randomly created, and 3 collective intelligence rules (follow-the-plurality rule, follow-the-most-confident rule, and follow-the-most-senior rule) were applied to combine the independent decisions into a final diagnosis. For different group sizes, the performance levels (i.e., percentage of correct diagnoses) of the 3 collective intelligence rules were compared with each other and against the average individual accuracy. Results. For all collective intelligence rules, combining independent decisions substantially increased performance relative to average individual performance. For groups of 4 or fewer, the follow-the-most-confident rule outperformed the other rules; for larger groups, the follow-the-plurality rule performed best. For example, combining 5 independent decisions using the follow-the-plurality rule increased diagnostic accuracy by 22 percentage points. These results were robust across case difficulty and expertise level. Limitations of the study include the use of simulated patients diagnosed by medical students. Whether results generalize to clinical practice is currently unknown. Conclusion. Combining independent decisions may substantially improve the quality of diagnoses in emergency medicine and may thus enhance patient safety.

Beyond Idea Generation: The Power of Groups in Developing Ideas

Brainstorming research has claimed that individuals are more creative than groups. However, these conclusions are largely based on measuring creativity by the number of ideas generated, and researchers have tended to neglect other important components of creativity, such as the quality of developed ideas. These studies aim to address this gap in the literature and investigate how well individuals and groups develop ideas. The first study compared collaborative groups, nominal groups (i.e., groups composed of individuals working separately), and individuals on developing an original design for a language-learning game. No differences were revealed between conditions on the game ratings. In the second study, one idea was preselected and given to the participants for further development. Groups received higher ratings in the marketability and overall categories than both nominal groups and individuals, and higher ratings in the fun category than individuals. The qualitative data showed that groups discussed a wider range of topics and topics related to marketability more than individuals did. Thus it appears that there are benefits to developing ideas in a collaborative group rather than individually. Possible explanations for the present findings are explored.

Reach and speed of judgment propagation in the laboratory

Significance Individual judgments, feelings, and behaviors can spread from person to person in social networks, similarly to the propagation of infectious diseases. Despite major implications for many social phenomena, the underlying social-contagion processes are poorly understood. We examined how participants’ perceptual judgments spread from one person to another and across diffusion chains. We gauged the speed, reach, and scale of social contagion. Judgment propagation tended to slow down with increasing social distance from the source. Crucially, it vanished beyond a social horizon of three to four people. These results advance the understanding of some of the mechanisms underlying social-contagion phenomena as well as their scope across domains as diverse as political mobilization, health practices, and emotions. In recent years, a large body of research has demonstrated that judgments and behaviors can propagate from person to person. Phenomena as diverse as political mobilization, health practices, altruism, and emotional states exhibit similar dynamics of social contagion. The precise mechanisms of judgment propagation are not well understood, however, because it is difficult to control for confounding factors such as homophily or dynamic network structures. We introduce an experimental design that renders possible the stringent study of judgment propagation. In this design, experimental chains of individuals can revise their initial judgment in a visual perception task after observing a predecessor’s judgment. The positioning of a very good performer at the top of a chain created a performance gap, which triggered waves of judgment propagation down the chain. We evaluated the dynamics of judgment propagation experimentally. Despite strong social influence within pairs of individuals, the reach of judgment propagation across a chain rarely exceeded a social distance of three to four degrees of separation. Furthermore, computer simulations showed that the speed of judgment propagation decayed exponentially with the social distance from the source. We show that information distortion and the overweighting of other people’s errors are two individual-level mechanisms hindering judgment propagation at the scale of the chain. Our results contribute to the understanding of social-contagion processes, and our experimental method offers numerous new opportunities to study judgment propagation in the laboratory.

How thinking about groups is different from groupthink

Firstly, the effects of interventions are diluted by many confounding factors on the route from intervention to patient outcome. Each confounding factor on this route inevitably lowers the effect size of an intervention. Nevertheless, in order to achieve adequate power, studies of such interventions would be required to cover a variety of contexts, which would in turn introduce new confounders.

Identifying low test-taking effort during low-stakes tests with the new Test-taking Effort Short Scale (TESS) – development and psychometrics

BackgroundLow-stakes tests are becoming increasingly important in international assessments of educational progress, and the validity of these results is essential especially as these results are often used for benchmarking. Test scores in these tests not only mirror students’ ability but also depend on their test-taking effort. One way to obtain more valid scores from participating samples is to identify test-takers with low test-taking effort and to exclude them from further analyses. Self-assessment is a convenient and quick way of measuring test-taking effort. We present the newly developed Test-taking Effort Short Scale (TESS), which comprises three items measuring attainment value/intrinsic value, utility value, and perceived benefits, respectively.MethodsIn a multicenter validation study with N = 1837 medical students sitting a low-stakes progress test we analyzed item and test statistics including construct and external validity.ResultsTESS showed very good psychometric properties. We propose an approach using stanine norms to determine a cutoff value for identifying participants with low test-taking effort.ConclusionWith just three items, TESS is shorter than most established self-assessment scales; it is thus suited for administration after low-stakes progress testing. However, further studies are necessary to establish its suitability for routine usage in assessment outside progress testing.

Collaboration time influences information-sharing at work

Purpose Different length of collaboration with colleagues at work is a central feature of modern working life, and even more so in a work environment that is increasingly project focused and knowledge-intensive. Despite its practical importance there is little research on how the perceived costs and benefits in an information-sharing dilemma might change depending on collaboration length. Based on a social dilemma framework it is hypothesised that anticipated length of collaboration time will significantly influence the motivation to collaborate. Design An experimental scenario study (N=87) compared the willingness to work collaboratively, share information and help the partner in a long-term (two academic terms) vs. a short-term (one week) condition. Findings At first somewhat counterintuitively, participants were more helpful in the short-term, and insisted more on equality and disengaged more from a defecting partner - but not the project - in the long-term condition. People appear to focus more on the immediate task in short-term collaborations ― even at cost ― because the outcome is more important than the relationship, and more on setting norms for equality and reciprocity in long-term collaborations to avoid future exploitation. Practical implications The findings help understanding the motivation and the partner and task perception under different time conditions and support managing teams in an increasingly project-oriented work environment with changing partners and varying time frames. Originality To the authors’ knowledge, this is the first paper investigating the influence of anticipated collaboration time in information-sharing dilemmas.

Improving patient safety through better teamwork: how effective are different methods of simulation debriefing? Protocol for a pragmatic, prospective and randomised study

Introduction Medical errors have an incidence of 9% and may lead to worse patient outcome. Teamwork training has the capacity to significantly reduce medical errors and therefore improve patient outcome. One common framework for teamwork training is crisis resource management, adapted from aviation and usually trained in simulation settings. Debriefing after simulation is thought to be crucial to learning teamwork-related concepts and behaviours but it remains unclear how best to debrief these aspects. Furthermore, teamwork-training sessions and studies examining education effects on undergraduates are rare. The study aims to evaluate the effects of two teamwork-focused debriefings on team performance after an extensive medical student teamwork training. Methods and analyses A prospective experimental study has been designed to compare a well-established three-phase debriefing method (gather–analyse–summarise; the GAS method) to a newly developed and more structured debriefing approach that extends the GAS method with TeamTAG (teamwork techniques analysis grid). TeamTAG is a cognitive aid listing preselected teamwork principles and descriptions of behavioural anchors that serve as observable patterns of teamwork and is supposed to help structure teamwork-focused debriefing. Both debriefing methods will be tested during an emergency room teamwork-training simulation comprising six emergency medicine cases faced by 35 final-year medical students in teams of five. Teams will be randomised into the two debriefing conditions. Team performance during simulation and the number of principles discussed during debriefing will be evaluated. Learning opportunities, helpfulness and feasibility will be rated by participants and instructors. Analyses will include descriptive, inferential and explorative statistics. Ethics and dissemination The study protocol was approved by the institutional office for data protection and the ethics committee of Charité Medical School Berlin and registered under EA2/172/16. All students will participate voluntarily and will sign an informed consent after receiving written and oral information about the study. Results will be published.