The gap between game-theoretic predictions and actual choices people make in, for instance, gaming experiments has been over-interpreted as evidence against rationality of players. I consider a version of the ultimatum game and examine its equilibria under different assumptions about players’ preferences. Using standard notions of rationality I show that the discrepancy between the “normative” and the “descriptive” cannot be established by a simple comparison of what is predicted by the equilibrium choices and the actual choices

Debate regarding evidence based medicine in current state focuses on basic philosophical as-sumptions of paradigm announced in 1992 by EBM Working Group. One of the topic in this debate is clinical reasoning in light of medical decision-making. Polish literature still lacks of comprehensive presentation in this theoretical fi eld. In current article I present overview of models of clinical reasoning. I begin from the debate of rationality distinguishing two positions called meliorism and panglosianism. Next I proceed to elaboration of three models for clinical reasoning in context of meliorists position. It gives an opportunity to look closer for inferential rules of clinical decision-making and as a result may be precious perspective for future re-search and medical education.

In this article we attempt to summarize the fi ndings from a number of studies on the asymmetric dominance effect (attraction effect, decoy effect). This is a phenomenon where popularity of one of the decision alternatives increases when accompanied by a similar but inferior (dominated) option. Scientifi c research and numerous observational studies show that the attraction effect occurs in various fi elds, incl. the economy, politics, law or medicine. In the literature there are many ambiguities and contradictory theories about, for example, its determinants in the light of the dual-systems theory. It is not ntirely clear whether the phenomenon of asymmetric domination is the result of a refl ective, deliberative way of information processing or of quick and intuitive thinking. There is also no unequivocal answer to the question whether this effect is a manifestation of human irrationality or whether it is an adaptive and effective decision-making strategy in conditions of uncertainty and information noise. The article contains a broad overview of research on the effect of asymmetric dominance among people and animals. The hanges in the susceptibility to this effect across the lifespan are analysed. Finally, the paper discusses using the asymmetric dominance effect to achieve socially desirable goals as described in the theory of libertarian paternalism.

In this paper, we consider the illusion of control by using Bayesian updating as the rationality model. Our paper contributes twofold. First, we empirically verify that the illusion of control may have two concurrent sources, “emotional” and “rational”. The fi rst one produces biased Bayesian processing due to emotional engagement and the second one yields biases due to prior assumptions on the level of control. Second, we propose a method for identifying these two sources. Moreover we verifi ed two hypotheses H1: The emotional factor causes overestimation of the actual level of control. and H2: The rational factor is responsible for the reverse relationship between observed levels of the illusion of control in three separate situations, when subjects have significant control, moderate or no control. Only the hypothesis H2 received partial empirical support.

Indirect reciprocity explains exchange within large groups where a favour is returned by someone other than the beneficiary. Evolutionary games used to analyze this phenomenon are of two types: some authors show that simple strategies based on information about the past deeds of a partner are sufficient for indirect reciprocity to emerge; others indicate that complex strategies based on motivations have better dynamic properties. These complex strategies require knowledge of a considerable number of past interactions of partners and their former partners and use complicated reasoning. I present another approach to improve the performance of simple strategies using the ecological rationality concept. According to this approach, information can be useful in solving a problem even if it is not logically related to it. A probabilistic connection between information and an environmental criterion is sufficient. I present two simple strategies based on such connections. They use reference and experience. Neither needs information extending beyond the most recent interactions of chosen individuals. Using computer simulation I show that they can support indirect reciprocity. The strategies are particularly useful when conditions are unfavourable e.g. when the cost of helping is high and/or when information is difficult to obtain.

The dynamic development of experimental economics, in particular of experimental work in game theory, has contributed to the questioning of the basic assumptions of classical game theory: the rationality and self-interest assumption. In response, those assumptions are being modified and more realistic models of human behavior in situations which can be described as games are being developed. The article provides a short overview of the models that abandon the self-interest assumption. An account is given mostly of the distributional models (i.a. inequity aversion models, model of quasi-maximin preferences). The results of the experiments designed to test the rival distributional models of social preferences are also presented in the article, as well as of the experiments that assess to the role played by intention-based reciprocity in motivating human behavior.

In 1970 A.K. Sen formulated the "Liberal Paradox" and he proved that there was a conflict between individual rights (Sen's "condition of liberalism") and social rationality (Pareto optimality). This article contains an analysis of classical conditions in the context of this inconsistency and a new way of approaching this problem. The datum for these considerations was a supposition that the conflict can appear only in societies composed of people with nonliberal preferences. The liberality level of preferences can be described as a position in a two-dimensional space. The first dimension is "interested in my own problems" and the other is "protection of other people's rights". The main result indicates when the conflict between liberalism and optimality appears. All analyses were based on full sets of individual preferences for two selected situations (the first one: 2 persons and 4 social alternatives and the other one: 2 persons with strong preferences and 6 social alternatives).

The article presents an analysis of the effects of the list apparentment institution introduced in the electoral rule for the sejmik of voivodship (regional council) and of some other changes which also had significant consequences. The effect analysis of these institutional solutions required primarily a comparison of specific political parties’ election results with the results these parties would have got under the „old” electoral rule, assuming no change in voters’ preferences resulting from the change in law. The electoral rule amendment had a significant impact on the results of specific parties, as measured by the number of mandates gained. Then, the authors investigated a number of alternative coalition strategies available to political parties, elaborating on the issue of effectiveness in actions undertaken by collective actors such as political parties. The authors proved that the results of the elections concerned depended on coalition strategies, rather than on election rules. Some players in the electoral game failed to achieve effectiveness in the attainment of the ultimate objective, i.e. to maximise the number of mandates gained, but the assessment of effectiveness provides different results if we assume that an important objective (though not equally important) was to maximise the results of the relevant bloc formed by apparentment. A matter of concern in the new electoral rule is the violation in 26% of constituencies of the monotonny criterion in the distribution of mandates resulting from the distribution of votes. In their concluding remarks, the authors put forward a proposal for a change in the electoral rule that better reflects the profiles of individual preferences in the social choice, while maintaining the apparentment institution.

Artykuł przedstawia teorię partycypacji wyborczej wyrastającą z założeń o racjonalnym działaniu. Zapoczątkowany przez Anthony’ego Downsa nurt rozważań o zachowaniach wyborczych na pierwszy plan wysuwa instrumentalną motywację decyzji dotyczących udziału w głosowaniu. Analiza kosztów i korzyści przeprowadzana przez każdego wyborcę, biorąca pod uwagę jedynie korzyść płynącą z objęcia władzy przez preferowanego kandydata oraz szansę wpłynięcia na wynik wyborów, skłonić powinna wszystkich obywateli do absencji, co jednakże w rzeczywistości nie ma miejsca. Artykuł prezentuje kilka rozwiązań tego paradoksu partycypacji, ukazując na tle rozważań teoretycznych wyniki badań empirycznych nad absencją wyborczą.

Social choice theory contains a number of deductive theorems on voting Methods' properties, in particular "non-existence" theorems, stating that there is no voting method complying particular rationality condition (as insusceptibility to strategic voting). These theorems, though theoretically important, have limited practical implications. When no voting method guarantees rational choice, the question of risk level connected with particular methods is raised. Such a question can be partly answered by means of computer simulations. Although simulations' results have no deductive quality, often they could be treated as statistical hypotheses. Even if statistical interpretation is impossible, simulations' results could be helpful in resolving practical problems.