Ausgangspunkt dieser Dissertation ist, dass mit stabilen Präferenzen unvereinbares Verhalten für die Standardökonomik eine Herausforderung darstellt. Eines der sich stellenden Probleme ist, dass sich wandelnde Präferenzen der normativen Analyse abträglich sind: Wenn nicht vorhersagbar ist, ob und wie Präferenzen abhängig von der Situation und von institutionellen Arrangements variieren, lässt sich keine optimale Wirtschaftspolitik bestimmen. Es wird argumentiert, dass die Ökonomik daher auch in Betracht ziehen muss, wie Präferenzen evolvieren und wie ökonomische Akteure Informationen - z. B. Wahrscheinlichkeiten und Auszahlungen -verarbeiten. In den folgenden Kapiteln werden zwei Studien vorgestellt, die dieses Ziel verfolgen, indem sie den Prozess der Entscheidungsfindung experimentell untersuchen. Die erste Studie, "Kognitive Last erhöht Risikoaversion", zeigt, dass eine spezifische Änderung des Entscheidungsumfelds - nämlich eine Erhöhung der kognitiven Last - einen messbaren Einfluss auf die Risikoeinstellungen der Versuchspersonen hatte. Zudem werden die beobachteten Verhaltensänderungen in Verbindung zu existierenden Mehr-System-Modellen der Entscheidungsfindung gesetzt. Die ebenfalls gemessenen Reaktionszeiten bestätigt die Interpretation, dass die Entscheidungsfindung unter Risiko das Produkt interagierender Systeme im menschlichen Hirn ist. Die zweite Studie, "Soziales Lernen auf Finanzmärkten", verfolgt das Ziel, die normalerweise verborgenen Komponenten Präferenzen und Überzeugungen beobachtbar zu machen. Zu diesem Zweck absolvierten Versuchspersonen ein Experiment, während ihre Hirnaktivierung per funktioneller Magnetresonanztomografie gemessen wurde. Dies erweitert den analysierbaren Datensatz über die getroffenen Entscheidungen hinaus um Maße der Hirnaktivierung. Dadurch trägt diese Studie zur Identifizierung der Faktoren bei, die bestimmen, in welchem Umfang wir aus der Beobachtung der Entscheidungen anderer lernen. / The point of departure of this dissertation is that behavior which is inconsistent with stable preferences poses a challenge for mainstream economics. One of the issues that arise is that changing preferences are detrimental to the objective of normative economics: If one cannot predict whether and how people’s preferences vary across situations or institutions, one cannot determine which economic policy would be optimal. Based on this, it is argued that economics has to take into account how preferences evolve and how information - e.g., probabilities and payoffs - is processed by economic agents. In the following two chapters, two experimental studies are presented that pursue this goal by investigating the process by which people make decisions. The first study, "Cognitive load increases risk aversion," shows that a specific change in the environment - in this case, an increase in cognitive load - had a measurable impact on subjects’ risk attitudes. Importantly, it also relates the observed changes to existing dual-system models of decision making. The response times which were recorded in addition to subjects’ choices contribute to the interpretation of the study’s findings, since they support the view that decision making under risk is the product of interacting systems in the human brain. The second study, "Social learning in asset markets," has the objective of making the latent components preferences and beliefs observable. To this end, subjects participated in a social-learning experiment while their brain activation was recorded via functional magnetic-resonance imaging. This enlarges the analyzable dataset through measures of subjects’ brain activation in addition to subjects’ choices. In doing so, the study contributes to identifying the factors that shape to what extent we learn from observing the choices of other human beings.

Cette thèse rassemble trois essais sur la théorie axiomatique de la décision.Ils relèvent principalement de l’analyse épistémologique de cette théorie.Le premier essai, “Les limites de l’ordinalisme”, concerne la doctrine ordinaliste,qui a joué un rôle important dans la constitution de la théoriemicro-économique contemporaine. Dans un premier temps, nous définissonsabstraitement cette doctrine. Nous la caractérisons par la thèse suivant laquelledes données de choix ne peuvent pas rendre empiriquement signifiantesles propriétés non-ordinales de l’utilité. Dans un second temps, nous évaluonscette thèse, la confrontant à divers développements de la théorie de la décision,qui paraissent la remettre en cause. Nous montrons que, malgré lesapparences, cette thèse n’est pas remise en cause par les développementsthéoriques que nous étudions.Le deuxième essai, “L’analyse axiomatique et l’attitude par rapport aurisque”, porte sur le statut, en théorie de la décision, des concepts d’attitudepar rapport au risque. A première vue, l’analyse axiomatique n’exploite pasces idées-là. Ceci reflète une certaine neutralité des modèles de décision ausujet de l’attitude par rapport au risque. Mais un examen plus poussé permetde mettre en valeur ce que nous nommons la variation conditionnelle et lerenforcement de l’attitude par rapport au risque, établissant par là mêmel’importance axiomatique des concepts d’attitude par rapport au risque.Le troisième essai, “Les paris révèlent-ils les croyances ?”, examine la méthodeconsistant à identifier les croyances d’un agent à partir de ses préférences.Nous nous concentrons sur l’obstacle principal auquel cette méthodeest exposée, à savoir, le problème de l’utilité dépendante des états. En premierlieu, nous illustrons ce problème de manière détaillée, distinguant quatreformes de dépendance de l’utilité aux états. En second lieu, nous présentonset discutons une stratégie permettant, malgré la possibilité d’une telle dépendance,d’identifier les croyances. Cependant, pour résoudre ainsi le problème,il faut laisser la préférence s’étendre au-delà du choix. Nous défendons quetel doit être le cas dans toute solution complète au problème de l’utilitédépendante des états. Nous affirmons aussi que c’est là la principale leçonconceptuelle à tirer de ce problème, et montrons qu’elle intéresse tant leséconomistes que les philosophes. / This thesis consists of three essays on axiomatic decision theory. Theybelong primarily to the epistemological analysis of decision theory.The first essay, “The limits of ordinalism”, focuses on ordinalism, a doctrinethat was instrumental in the constitution of contemporary microeconomictheory. First, I provide an abstract definition of this doctrine.I characterize it by the following claim: if the underlying data are choicedata, then no non-ordinal property of utility can be empirically meaningful.Second, I evaluate the above claim. I confront this claim with variousdecision-theoretic developments which seem to question its validity. I showthat, despite appearances, this claim is not challenged by the theoreticaldevelopments in question.The second essay, “Axiomatic analysis and risk attitudes”, examines thestatus of risk attitude concepts in decision theory. At first sight, axiomaticanalysis does not rely on these concepts. This indicates a certain neutrality ofdecision models regarding risk attitudes. Further analysis, however, leads oneto recognize the importance of what I call the conditional variation and thestrengthening of risk attitudes. This establishes the axiomatic significance ofrisk attitude concepts.The third essay, “Do bets reveal beliefs?”, examines the preference-basedapproach to the identification of beliefs. It focuses on the main problem towhich this approach is exposed, namely state-dependent utility. First, theproblem is illustrated in full detail. Four types of state-dependent utility issuesare distinguished. Second, a strategy for identifying beliefs under statedependentutility is presented and discussed. For the problem to be solvedfollowing this strategy, however, preferences need to extend beyond choices. Iargue that this is a necessary feature of any complete solution to the problemof state-dependent utility. I also claim that this is the main conceptuallesson to draw from this problem. I explain why this lesson is of interest toeconomists and philosophers alike.

Title: The importance of risk for the empowerment of individuals with mental disabilities and the possibility of taking in DZR Terezin Objectives: The aim of this paper is to examine the phenomenon of risk-taking and its importance in the process of empowerment of persons with mental disabilities in social services. Methods: In empirical research we were surveyed employee attitudes DZR Terezin to the issue of risk in social services. In the first part of the research was to look at the views and attitudes of social workers employed form questionnaire (Lepešková, 2013) in a group of 22 employees - women with a mean age of 46 years. The second part of the research were semi-structured interviews with staff enabling deeper qualitative analysis of the problem. Talks with 7 employees participated. 6 women and 1 man. The recording was used edited form an interview. Results: The survey both methods show that the respondents as one of the most important tasks when working with the risks and support to people deemed to support their independence. The aim is to get clients to the extent possible, make their own decisions about their own lives. An essential element in this process is considered self- management. The client does not passively wait to social service workers determine what to do and what will...