Vasopressin increases human risky cooperative behavior.

The history of humankind is an epic of cooperation, which is ubiquitous across societies and increasing in scale. Much human cooperation occurs where it is risky to cooperate for mutual benefit because successful cooperation depends on a sufficient level of cooperation by others. Here we show that arginine vasopressin (AVP), a neuropeptide that mediates complex mammalian social behaviors such as pair bonding, social recognition and aggression causally increases humans' willingness to engage in risky, mutually beneficial cooperation. In two double-blind experiments, male participants received either AVP or placebo intranasally and made decisions with financial consequences in the "Stag hunt" cooperation game. AVP increases humans' willingness to cooperate. That increase is not due to an increase in the general willingness to bear risks or to altruistically help others. Using functional brain imaging, we show that, when subjects make the risky Stag choice, AVP down-regulates the BOLD signal in the left dorsolateral prefrontal cortex (dlPFC), a risk-integration region, and increases the left dlPFC functional connectivity with the ventral pallidum, an AVP receptor-rich region previously associated with AVP-mediated social reward processing in mammals. These findings show a previously unidentified causal role for AVP in social approach behavior in humans, as established by animal research.

Ultimatum bargaining over losses and gains - An experimental comparison.

Subjects in the loss domain tend to split payoffs equally when bargaining. The ultimatum game offers an ideal mechanism through which social scientists can investigate whether equal splits are the consequence of the proposers' generosity or due to their anticipation that the responders will reject lower offers. This paper experimentally compares ultimatum bargaining that takes place in a loss domain with that under a gains domain. The results reveal that, although responders do not expect more in the loss domain, proposers do make higher offers. As such, proposers reach agreements more often in the loss domain than they do in the gains domain, and responders receive higher payoffs.

Case vignettes based on EQ-5D to elicit stated preferences for health services utilization from the insurees' perspective.

BACKGROUND: There is little evidence as to why or why not insurees decide to seek medical services. Steps prior to the entry of the insuree into the professional health care system have not been sufficiently examined and can only be partially described by secondary data of the statutory health insurance (SHI). We report the first investigation using case vignettes based on the generic health-related quality of life questionnaire EQ-5D as part of a choice study to assess insurees' stated preferences in health services utilization. METHODS: We invited 1500 randomly selected citizens (age 30 to 70 years) from the East German state of Saxony-Anhalt by postal mail to participate in the choice study. Attributes of the case vignettes involved in choice tasks were the five dimensions of the EQ-5D. We used multilevel mixed effects logit regression analysis with the dependent variables: preference to seek medical services (model 1) and preferred time until consultation (model 2) for the assessed case vignette. The EQ-5D attributes of the case vignettes and participant characteristics served as the independent variables. We also included the respondent's certainty of choosing from the choice set, and the order of questions of the questionnaire as control variables. RESULTS: Of the 1500 questionnaires 683 were evaluable (net response rate 48.0%). On the level of the case vignettes, problems in all five dimensions of the EQ-5D were statistically significant factors of the estimated likelihood to seek medical services (model 1). On the respondent level, there was a significant relationship between the preference for medical consultation for the assessed case vignette and the respondent's gender, age, educational level, the existence of a regular doctor, and the certainty of choosing from the choice set. Problems in four of the five dimensions of the EQ-5D (except anxiety/depression) of the case vignettes were significantly associated with the preferred time until consultation (model 2). On the respondent level, gender, educational level, the certainty of choosing from the choice set, and the order of questions of the questionnaire were significant determinants of the time until consultation. CONCLUSIONS: Our study offers a promising new approach for the national and cross-national study of preferences in health services utilization from the insurees' perspective.

Improving Likert scale big data analysis in psychometric health economics: reliability of the new compositional data approach.

Bipolar psychometric scales data are widely used in psychologic healthcare. Adequate psychological profiling benefits patients and saves time and costs. Grant funding depends on the quality of psychotherapeutic measures. Bipolar Likert scales yield compositional data because any order of magnitude of agreement towards an item assertion implies a complementary order of magnitude of disagreement. Using an isometric log-ratio (ilr) transformation the bivariate information can be transformed towards the real valued interval scale yielding unbiased statistical results increasing the statistical power of the Pearson correlation significance test if the Central Limit Theorem (CLT) of statistics is satisfied. In practice, however, the applicability of the CLT depends on the number of summands (i.e., the number of items) and the variance of the data generating process (DGP) of the ilr transformed data. Via simulation we provide evidence that the ilr approach also works satisfactory if the CLT is violated. That is, the ilr approach is robust towards extremely large or infinite variances of the underlying DGP increasing the statistical power of the correlation test. The study generalizes former results pointing out the universality and reliability of the ilr approach in psychometric big data analysis affecting psychometric health economics, patient welfare, grant funding, economic decision making and profits.

Enforcement of Fairness Norms by Punishment: A Comparison of Gains and Losses.

Although in everyday life decisions about losses are prevalent (e.g., the climate crisis and the COVID-19 crisis), there is hardly any research on decisions in the loss domain. Therefore, we conducted online experiments with a sample of 672 participants (mostly students), using third-party punishment dictator games (DGs) in the loss domain to explore the impact of losses and punishment threats on the conformity to the fairness norm. Subjects in the treatment condition have to divide a loss of -10 € with the threat of a third-party punishment with different strengths (control: gains, no punishment). Overall, the statistical evidence seems rather weak, but when it comes to losses, subjects are more rational and straightforward with their words and deeds than with gains. Therefore, in the loss domain, subjects are more likely to believe that the fairness norm should be followed, and they subjectively perceive that the others do as well. Furthermore, although dictators' decisions are more selfish in the loss domain, dictators there react more strongly to the punishment threat by reducing their demands than in the gains domain. This holds as long as the punishment threat is strong enough, as judged from a rational perspective.

Which Expectations to Follow: The Impact of First- and Second-Order Beliefs on Strategy Choices in a Stag Hunt Game.

Many situations require coordinated actions of individuals to achieve common goals. Such situations include organizing mass protests or adjusting behavior to new behavioral recommendations that aim to slow down the spread of a contagious disease. However, there is a risk of coordination failure in such situations that can lead to a worse outcome for those who acted in a coordinated manner than for those who chose not to. In this paper, we investigate the main determinant of individuals' decisions in these situations to determine whether beliefs regarding the action of others (empirical expectations), beliefs regarding others' beliefs (normative expectations), or risk attitudes are dominant determinants. To this end, we conducted an experiment analyzing the relationship between an individual's choices in a stag hunt game, their probabilistic empirical and normative expectations (i.e., first-order and second-order beliefs, respectively), and their risk attitudes. Our central finding is that expectations, not risk attitudes, explain individuals' strategy selection. In addition, we found evidence that normative expectations are a better predictor of strategy selection than empirical expectations. This could have implications for developing more targeted strategies intended to promote new behavioral standards and to guide individuals' behavior toward a welfare-maximizing equilibrium.

Patient-Reported Outcome Measures in Liver and Gastrointestinal Cancer Randomized Controlled Trials.

OBJECTIVE: For many years, outcomes such as mortality and morbidity were the standard for evaluating oncological treatment effectiveness. With the introduction of patient-reported outcome measures (PROMs), the focus shifted from a mere extension of a patient's life or release from disease to the improvement of a multilayered concept of health, decisively affecting life satisfaction. In this study, we deal with the topic of PROMs in liver and gastrointestinal randomized controlled trials. RESULTS: The final database included 43 papers reporting results of randomized controlled trials (RCTs) for liver or gastrointestinal cancer interventions where one of the primary or secondary outcomes was a health-related quality of life measure. The most often used PROM was the European Organization for Research and Treatment of Cancer Quality of Life questionnaire (EORTC QLQ-C30) for both liver cancer and gastrointestinal cancer (in 62% of gastrointestinal cancer studies and 57% of liver cancer studies). For the gastrointestinal cancer group, the QLQ-STO22, a cancer-specific extension of the QLQ-C30, was the second most commonly used PROM. In liver cancer, the generic PROM Short Form 36 and the EORTC QLQ-HCC18, a cancer-specific extension of the QLQ-C30, were the second most commonly used PROMs. CONCLUSION: We found that RCTs often do not include comprehensive quality-of-life measures. When quality of life is part of an RCT, it is often only a secondary outcome. For a holistic view of the patient, a stronger integration and weighting of patient-reported outcomes in RCTs would be desirable.

Experiments on norm focusing and losses in dictator games.

We conducted experiments on norm focusing. The tests were carried out with two versions of dictator games: in one version of the game, the dictator had to allocate a gain of €10, while in the other version, a loss of €-10 needs to be allocated. In a first treatment, we focused subjects on the average giving in similar previous dictator games. The second treatment focused subjects on the behaviour of what a self-interested actor should do. In total, N = 550 participants took part in our experiments. We found (1) a significant difference in giving behaviour between gain and loss treatments, with subjects being moderately more self-interested in the loss domain, (2) a significant effect of focusing subjects on the average behaviour of others, but (3) no effect of focusing subjects on the behaviour of self-interested actors.

Identification of Relevant Attributes for Liver Cancer Therapies (IRALCT): a maximum-difference-scaling analysis.

The Identification of Relevant Attributes for Liver Cancer Therapies (IRALCT) project is intended to provide new insights into the relevant utility attributes regarding therapy choices for malignant primary and secondary liver tumors from the perspective of those who are involved in the decision-making process. It addresses the potential value of taking patients' expectations and preferences into account during the decision-making and, when possible, adapting therapies according to these preferences. Specifically, it is intended to identify the relevant clinical attributes that influence the patients', medical laymen's, and medical professionals' decisions and compare the three groups' preferences. We conducted maximum difference (MaxDiff) scaling among 261 participants (75 physicians, 97 patients with hepatic malignancies, and 89 medical laymen) to rank the importance of 14 attributes previously identified through a literature review. We evaluated the MaxDiff data using count analysis and hierarchical Bayes estimation (HB). Physicians, patients, and medical laymen assessed the same 7 attributes as the most important: probability (certainty) of a complete removal of the tumor, probability of reoccurrence of the disease, pathological evidence of tumor removal, possible complications during the medical intervention, welfare after the medical intervention, duration and intensity of the pain, and degree of difficulty of the medical intervention. The cumulative relative importance of these 7 attributes was 88.3%. Our results show that the physicians', patients', and medical laymen's preferences were very similar and stable.Trial registration DRKS-ID of the study: DRKS00013304, Date of Registration in DRKS: 2017/11/16.

Acute tryptophan depletion in healthy subjects increases preferences for negative reciprocity.

Reciprocity motivates to reward those who are kind (= positive reciprocity) and to punish those who are unkind (= negative reciprocity). The neurotransmitter serotonin (5-HT) modulates human behavior in numerous social situations, such as retaliation in response to perceived unfairness. In a placebo-controlled study, we used acute tryptophan depletion (ATD) to investigate the influence of available serotonin on choice behavior and reciprocity in the Hawk-Dove game. This game illustrates a conflict situation and incorporates two potential strategies: the cooperative Dove strategy and the uncooperative, more aggressive Hawk strategy. After strategic choices, we elicited the subjects' expectations (= beliefs) regarding the opponent's choices and controlled for risk preferences and current mood. We defined strategy choices as negative reciprocity when the participants opted for Hawk in response to an expected Hawk. We hypothesized that the ATD-induced reduction of 5-HT availability would increase participants' preferences for negative reciprocity. Generalized estimating equations reveal no significant main effect of ATD on assessed belief, mood, or risk attitude. But assessment of ATD's marginal effects over beliefs suggests that ATD significantly increases the tendency for negative reciprocity, whereas positive reciprocity (Dove in response to an expected Dove) is unaffected. We could therefore demonstrate that 5-HT availability mediates (negative) reciprocal behavior in social decision-making.

A registered replication study on oxytocin and trust.

In an influential paper, Kosfeld et al. (2005) showed that intranasal administration of oxytocin (OT) increases the transfers made by investors in the trust game-suggesting that OT increases trust in strangers. Subsequent studies investigating the role of OT in the trust game found inconclusive effects on the trusting behaviour of investors but these studies deviated from the Kosfeld et al. study in an important way-they did not implement minimal social contact (MSC) between the investors and the trustees in the trust game. Here, we performed a large double-blind and placebo-controlled replication study of the effects of OT on trusting behaviour that yields a power of more than 95% and implements an MSC condition as well as a no-social-contact (NoC) condition. We find no effect of OT on trusting behaviour in the MSC condition. Exploratory post hoc analyses suggest that OT may increase trust in individuals with a low disposition to trust in the NoC condition, but this finding requires confirmation in future research. PROTOCOL REGISTRATION: The stage 1 protocol for this Registered Report was accepted in principle on 19 October 2018. The protocol, as accepted by the journal, can be found at https://doi.org/10.6084/m9.figshare.11980368.

Older adults show a reduced tendency to engage in context-dependent decision biases.

When we make decisions, we usually consider the context. This can sometimes lead to suboptimal choices or choice abnormalities. One such abnormality is the compromise effect, according to which deciders tend to favour options positioned as a compromise in an available set of extreme options. Theoretical accounts consider that these effects relate to available cognitive resources, which, in turn, have been found to depend on an individual's dopaminergic innervation. Referring to a correlative triad between cognition, dopamine and aging, the present study demonstrates that the compromise effect is replicable in a group of younger adults (n = 27, 20-32 years of age) yet is attenuated in older adults (n = 27, 62-80 years of age). Results from an [18F]-FDOPA-PET analysis in older adults indicate a positive association between older adults' inclination to engage in compromise effects and their striatal dopamine synthesis capacity. These results demonstrate altered context-dependent decision biases in older adults and suggest a neuromodulatory mechanism underlying this irregular choice.

Dataset and protocols on the applicability of the BDM mechanism in product evaluation.

Understanding how to best elicit consumers' willingness to pay (WTP) for goods in an incentive-aligned way is one of the cornerstones in marketing planning decisions and consumer welfare theory. This article provides a dataset from an experiment with n = 107 consumers that measured the WTP for a set of eight real consumer goods by means of the Becker-DeGroot-Marschak (BDM) mechanism, entailing a facultative resell option. This procedure allows for testing the empirical incentive-compatibility of the BDM mechanism. Despite early evidence on lottery choices or fictitious goods, the empirical incentive-compatibility of the BDM mechanism in case of real consumer goods remains an under-researched topic. For the first time, we provide a dataset on consumers' WTP statements in such a paradigm. More precisely, this article provides experimental protocols, manipulation-check questions, full raw datasets, summary statistics, and model properties related to the research article entitled "On the applicability of the BDM mechanism in product evaluation" [Lichters et al., 2019]. The raw dataset allows for an independent analysis of consumers' bidding behavior for multiple consumer goods. Thus, future researchers might use our dataset in a meta-analytic fashion for their own research on WTP elicitation.

Health Technology Assessments in Radiology in Germany: Lack of Demand, Lack of Supply. / Health-Technology-Assessments in der Radiologie in Deutschland: Fehlende Nachfrage, fehlendes Angebot.

BACKGROUND: Health technology assessments (HTAs) are an interdisciplinary method to support sustainable, evidence-based healthcare decisions. They systematically assess medical products, procedures, and technologies with respect to medical, economic, legal, social, and ethical aspects. METHOD: This review analyzes the current use of HTAs in radiology in Germany and discusses challenges associated with HTAs. In particular, incentive structures of various players in the healthcare field involved in HTA implementation are considered for both the inpatient and outpatient sectors. Taking into account that the Joint Federal Committee (G-BA) has different authority between sectors ("ban reservation" for inpatients and "authorization right" for outpatients), we focus on the repercussions on reimbursement for new diagnosis or treatment methods by statutory health insurance companies. RESULTS: The G-BA's authority implicitly creates a paradox in terms of incentives to implement and finance HTAs: in the outpatient sector HTAs are considered necessary to evaluate new medical services while players may not have sufficient incentive to implement and finance HTAs in the inpatient sector. CONCLUSION: Characteristics of HTAs differ widely with respect to the items to be assessed. Therefore, an HTA for drug effectiveness is not easily transferable to radiological procedures. Within radiology, each method must be assessed individually (e. g. according to tumor stage). Despite these challenges, systematic compilation and critical assessment (regarding both cost and medical effectiveness) of available evidence should be a basic component of evidence-based radiology. As companies in healthcare fail to invest in studies that advance evidence-based radiology and considering the lack of incentive for such investments, public funding institutions need to accept the challenge to support studies that assess the benefit of radiological procedures. KEY POINTS: · HTAs should be a basic component of evidence-based radiology.. · G-BA's authority implicitly creates a paradox in terms of inventives to implement and finance HTAs.. · University hospitals and public funding institutions need to support studies that assess the benefit of radiological procedures.. CITATION FORMAT: · Winkelmann C, Neumann T, Zeidler J et al. Health Technology Assessments in Radiology in Germany: Lack of Demand, Lack of Supply. Fortschr Röntgenstr 2019; 191: 635 - 642.

Insurees' preferences in hospital choice-A population-based study.

In Germany, the patient himself makes the choice for or against a health service provider. Hospital comparison websites offer him possibilities to inform himself before choosing. However, it remains unclear, how health care consumers use those websites, and there is little information about how preferences in hospital choice differ interpersonally. We conducted a Discrete-Choice-Experiment (DCE) on hospital choice with 1500 randomly selected participants (age 40-70) in three different German cities selecting four attributes for hospital vignettes. The analysis of the study draws on multilevel mixed effects logit regression analyses with the dependent variables: "chance to select a hospital" and "choice confidence". Subsequently, we performed a Latent-Class-Analysis to uncover consumer segments with distinct preferences. 590 of the questionnaires were evaluable. All four attributes of the hospital vignettes have a significant impact on hospital choice. The attribute "complication rate" exerts the highest impact on consumers' decisions and reported choice confidence. Latent-Class-Analysis results in one dominant consumer segment that considered the complication rate the most important decision criterion. Using DCE, we were able to show that the complication rate is an important trusted criterion in hospital choice to a large group of consumers. Our study supports current governmental efforts in Germany to concentrate the provision of specialized health care services. We suggest further national and cross-national research on the topic.

The influence of probability format on elicited certainty equivalents.

We compare six different formats for the presentation of probabilities, in terms of the certainty equivalents that they elicit from human participants, and the probability-weighting parameters that participants' decisions imply. We find substantial differences among formats, including a visual analogue of the ratio bias. The results indicate that experimental results concerning decision making under risk can be greatly affected by the presentation format employed.

Which patients do I treat? An experimental study with economists and physicians.

This experiment investigates decisions made by prospective economists and physicians in an allocation problem which can be framed either medically or neutrally. The potential recipients differ with respect to their minimum needs as well as to how much they benefit from a treatment. We classify the allocators as either 'selfish', 'Rawlsian', or 'maximizing the number of recipients'. Economists tend to maximize their own payoff, whereas the physicians' choices are more in line with maximizing the number of recipients and with Rawlsianism. Regarding the framing, we observe that professional norms surface more clearly in familiar settings. Finally, we scrutinize how the probability of being served and the allocated quantity depend on a recipient's characteristics as well as on the allocator type.JEL Classification: A13, I19, C91, C72.

Different methods to define utility functions yield similar results but engage different neural processes.

Although the concept of utility is fundamental to many economic theories, up to now a generally accepted method determining a subject's utility function is not available. We investigated two methods that are used in economic sciences for describing utility functions by using response-locked event-related potentials in order to assess their neural underpinnings. For determining the certainty equivalent, we used a lottery game with probabilities to win p = 0.5, for identifying the subjects' utility functions directly a standard bisection task was applied. Although the lottery tasks' payoffs were only hypothetical, a pronounced negativity was observed resembling the error related negativity (ERN) previously described in action monitoring research, but this occurred only for choices far away from the indifference point between money and lottery. By contrast, the bisection task failed to evoke an remarkable ERN irrespective of the responses' correctness. Based on these findings we are reasoning that only decisions made in the lottery task achieved a level of subjective relevance that activates cognitive-emotional monitoring. In terms of economic sciences, our findings support the view that the bisection method is unaffected by any kind of probability valuation or other parameters related to risk and in combination with the lottery task can, therefore, be used to differentiate between payoff and probability valuation.