The experimental tasks will be administered on a computer in groups of 6-15 people, separately from any other experiments running in a laboratory and during a single experimental session. Experiment will consist of instructions screen where the participants will be explained their task and several separate screens presenting experimental tasks. In the case of the test of knowledge of Greece numerals and in the case of the Personal Need for Structure inventory all individual items will be presented on one single screen. In the case of other task sets individual items will be preseneted one by one, each on a single screen. Participants are instructed to move only forward and to not return to already solved tasks/answered questions. Participants' responses on presented items will be recorded.