Contributions in Merlin

Der Krankheitsbegriff der Ökonomie wird in Abgrenzung zum allgemein üblichen Krankheitsbegriff definiert. Darauf wird die mangelhafte Funktionsweise der Gesundheitsmärkte dargelegt, bevor die Vor- und Nachteile politischer Lösungsvorschläge beleuchtet werden.

Relative Einkommensunterschiede lösen innerhalb einer Referenzgruppe oftmals Neid aus. Damit wird das soziale Verhalten und die individuelle Leistungsbereitschaft beeinflusst. In der ökonomischen Forschung ist dennoch bislang der Zusammenhang zwischen relativen Einkommensunterschieden und individueller Leistung wenig untersucht worden. Ein wesentlicher Grund dafür ist sicherlich die schwierige Messbarkeit von „Leistung“. Unser Beitrag analysiert den Einfluss von relativen Einkommensunterschieden auf die Leistung von Fußballprofis der deutschen Bundesliga, weil deren Leistung erfolgreich erfasst wurde. Insgesamt werden 1040 Spieler über einen Zeitraum von 8 Spielzeiten zwischen 1995 und 2004 untersucht. Relative Einkommensunterschiede zwischen Mannschaftskollegen erweisen sich als entscheidender Einfluss auf die individuelle Leistung der Spieler. Eine Verschlechterung in der relativen Einkommensposition vermindert ceteris paribus die individuelle Leistungsbereitschaft. Eine höhere Einkommensungleichheit verstärkt solche positionalbedingten Externalitäten. Auch eine Veränderung der Teamkonstellation bewirkt signifikante Änderungen der individuellen Leistungen.

BACKGROUND: It has been suggested that some psychotic symptoms reflect ‘aberrant salience’, related to dysfunctional reward learning. To test this hypothesis we investigated whether patients with schizophrenia showed impaired learning of task-relevant stimulusreinforcement associations in the presence of distracting task-irrelevant cues. METHODS: We tested 20 medicated patients with schizophrenia and 17 controls on a reaction time game, the Salience Attribution Test. In this game, participants made a speeded response to earn money in the presence of conditioned stimuli (CSs). Each CS comprised two visual dimensions, colour and form. Probability of reinforcement varied over one of these dimensions (task-relevant), but not the other (task-irrelevant). Measures of adaptive and aberrant motivational salience were calculated on the basis of latency and subjective reinforcement probability rating differences over the task-relevant and task-irrelevant dimensions respectively. RESULTS: Participants rated reinforcement significantly more likely and responded significantly faster on high-probability reinforced relative to lowprobability reinforced trials, representing adaptive motivational salience. Patients exhibited reduced adaptive salience relative to controls, but the two groups did not differ in terms of aberrant salience. Patients with delusions exhibited significantly greater aberrant salience than those without delusions, and aberrant salience also correlated with negative symptoms. In the controls, aberrant salience correlated significantly with ‘introvertive anhedonia’ schizotypy. CONCLUSIONS: These data support the hypothesis that aberrant salience is related to the presence of delusions in medicated patients with schizophrenia, but are also suggestive of a link with negative symptoms. The relationship between aberrant salience and psychotic symptoms warrants further investigation in unmedicated patients.

In this note, we describe a variant of dynamic causal modelling for evoked responses as measured with electroencephalography or magnetoencephalography (EEG and MEG). We depart from equivalent current dipole formulations of DCM, and extend it to provide spatiotemporal source estimates that are spatially distributed. The spatial model is based upon neural-field equations that model neuronal activity on the cortical manifold. We approximate this description of electrocortical activity with a set of local standing-waves that are coupled though their temporal dynamics. The ensuing distributed DCM models source as a mixture of overlapping patches on the cortical mesh. Time-varying activity in this mixture, caused by activity in other sources and exogenous inputs, is propagated through appropriate lead-field or gain-matrices to generate observed sensor data. This spatial model has three key advantages. First, it is more appropriate than equivalent current dipole models, when real source activity is distributed locally within a cortical area. Second, the spatial degrees of freedom of the model can be specified and therefore optimised using model selection. Finally, the model is linear in the spatial parameters, which finesses model inversion. Here, we describe the distributed spatial model and present a comparative evaluation with conventional equivalent current dipole (ECD) models of auditory processing, as measured with EEG.

Over the last 2 decades, a large number of neurophysiological and neuroimaging studies of patients with schizophrenia have furnished in vivo evidence for dysconnectivity, ie, abnormal functional integration of brain processes. While the evidence for dysconnectivity in schizophrenia is strong, its etiology, pathophysiological mechanisms, and significance for clinical symptoms are unclear. First, dysconnectivity could result from aberrant wiring of connections during development, from aberrant synaptic plasticity, or from both. Second, it is not clear how schizophrenic symptoms can be understood mechanistically as a consequence of dysconnectivity. Third, if dysconnectivity is the primary pathophysiology, and not just an epiphenomenon, then it should provide a mechanistic explanation for known empirical facts about schizophrenia. This article addresses these 3 issues in the framework of the dysconnection hypothesis. This theory postulates that the core pathology in schizophrenia resides in aberrant N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic plasticity due to abnormal regulation of NMDARs by neuromodulatory transmitters like dopamine, serotonin, or acetylcholine. We argue that this neurobiological mechanism can explain failures of self-monitoring, leading to a mechanistic explanation for first-rank symptoms as pathognomonic features of schizophrenia, and may provide a basis for future diagnostic classifications with physiologically defined patient subgroups. Finally, we test the explanatory power of our theory against a list of empirical facts about schizophrenia.

1990 war die Schweiz das erste europäische Land, das Managed Care ­Modelle (MC) in seiner sozialen Krankenversicherung zuliess. Nach einem schwerfälligen Start entwickelt sich dieser Versicherungszweig stetig weiter. 2008 hatten sich 30% der Schweizer Bevölkerung für einen Managed Care Vertrag entschieden im Vergleich zu 5,3% im Jahre 1997. – Die Frage ist nun: Wieviel wird dank MC gespart? Eine empirische Analyse ging der Sache auf den Grund.

The paper investigates the relationship between pro-social norms and its implications for improved environmental outcomes. This is an area, which has been neglected in the environmental economics literature. We provide empirical evidence to demonstrate a robust link between perceived environmental cooperation (reduced public littering) and increased voluntary environmental morale. For this purpose we use European Values Survey (EVS) data for 30 European countries. We also demonstrate that Western European countries are more sensitive to perceived environmental cooperation than the public in Eastern Europe. Interestingly, the results also demonstrate that environmental morale is strongly correlated with several socio-economic and environmental variables. Several robustness tests are conducted to check the validity of the results.

In this paper, we investigate the effects of competition on bargained outcomes. We show that the neglect of either fairness concerns or decision errors will prevent a satisfactory understanding of how competition affects bargaining. We conducted experiments which demonstrate that introducing a small amount of competition to a bilateral ultimatum game – by adding just one competitor – induces large behavioral changes among responders and proposers, causing large changes in accepted offers. Models that assume that all people are self-interested and fully rational do not adequately explain these changes. We show that a model which combines heterogeneous fairness concerns with decision errors correctly predicts the comparative static effects of changes in competition. Moreover, the combined model is remarkably good at predicting the entire distribution of offers in many different competitive situations.

In this paper, we provide evidence for functional asymmetries in forward and backward connections that define hierarchical architectures in the brain. We exploit the fact that modulatory or nonlinear influences of one neuronal system on another (i.e., effective connectivity) entail coupling between different frequencies. Functional asymmetry in forward and backward connections was addressed by comparing dynamic causal models of MEG responses induced by visual processing of normal and scrambled faces.We compared models with and without nonlinear (between-frequency) coupling in both forward and backward connections. Bayesian model comparison indicated that the best model had nonlinear forward and backward connections. Using the best model we then quantified frequency-specific causal influences mediating observed spectral responses. We found a striking asymmetry between forward and backward connections; in which high (gamma) frequencies in higher cortical areas suppressed low (alpha) frequencies in lower areas. This suppression was significantly greater than the homologous coupling in the forward connections. Furthermore, exactly the asymmetry was observed when we examined face-selective coupling (i.e., coupling under faces minus scrambled faces). These results highlight the importance of nonlinear coupling among brain regions and point to a functional asymmetry between forward and backward connections in the human brain that is consistent with anatomical and physiological evidence from animal studies. This asymmetry is also consistent with functional architectures implied by theories of perceptual inference in the brain, based on hierarchical generative models.