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 is a review of selected methods in the of the decision making aiding in the project planning processes. It may be helpful in choosing a method for the analysis of the project decision making.

The article presents an empirical research which aimed at verifying if participation in a cooperation or competition training determined future behaviors during an anonymous, two-person trust game. We applied two variants of training: active and passive. The main hypothesis claimed that participation in a cooperation training activates the social norm of cooperation and induces more cooperative choices in trust games, whereas participation in a competition training reduces the willingness for cooperative choices. We also predicted that an active training would be more effective in activating cooperation and competition norms than a passive one. Finally, it was expected that interrelation of a cooperative decision in a more risky game would reduce the influence of a training-activated norm on the final decision. The results of the experiment confirmed all three hypotheses.