- Set of 15 Greek numerals used for testing the level of participants' familiarity with this type of numerical notation: VI, XV, IV, I, VII, VIII, XI, XIII, IX, II, V, XIV, XII, X, III. Participants's task will be to rewrite these Greek numerals in Indo-Arabic numerical notation. - Matchstick algebra tasks for control group (IV = III + III, VII = XI - II, VII = VI + III, XIII = VII + IV, VIII = VI + IV, VI = VIII - IV, IX = VI + V, XII = VIII + VI, VI = VII - III) and for experimental group (IV = III + III, VI = VII + I, I = II + II, XI = III + III, III = III + III, IV = III – I, IX = VII + III, VI = VI + I, V = III + III). The tasks were created on the basis of Knoblich et al.'s (1999) "taxonomy" of matchstick algebra tasks. The last three tasks for participants from experimental group are unsolvable. - Tables of frequencies that show how many times a heads or tails were produced from 100 trials. These data shows 8 trials on which 47, 51, 55, 59, 63, 70, 87, and 99 heads (males) were obtained. Participants will receive following psychokines cover story: *A group of scientists investigating paranormal phenomena have conducted a series of experiments testing people who claim to possess psychic powers. All of these people say that they have psychokinetic abilities: they believe that they can influence the outcome of a coin toss. The scientists tested this claim by flipping a fair coin 100 times in front of each person as they focus their psychic energies. Under normal circumstances, a fair coin produces heads and tails with equal probability. The results of these experiments are shown below: the identities of the people are concealed with subject numbers, but you are given the number of times the coin came up heads or tails while that person was focusing their psychic energies.* The posterior instructions for the psychokinesis condition will be *For each of the lines below, please rate HOW LIKELY you think it is that the person has psychic powers, taking into account the results of the experiment. Use a scale from 1 to 10, where 1 indicates NOT AT ALL LIKELY and 10 indicates EXTREMELY LIKELY.* The coincidence instructions for the psychokinesis condition will ask people to choose between a mere coincidence and evidence: *For each of the lines below, please decide whether you think the results for that person are JUST A COINCIDENCE, or COMPELLING EVIDENCE for them having psychic powers, by checking either the COINCIDENCE or the EVIDENCE box.* (taken from Griffiths & Tenenbaum, 2007) - 12 images ("maps") containing points ("impacts of bombs") at different locations within a 10 by 10 square, ranging from -5 to 5 in two directions. These images were generated on the basis of parameters taken from Griffiths and Tenenbaum (2007). - [Personal Need for Structure][1] inventory (Thompson, Naccarato, & Parker, 1992; Neuberg & Newsom, 1993). All materials will be presented in Czech language. [1]: https://psychology.clas.asu.edu/sites/default/files/Personal%20need%20for%20structure-%20Individual%20differences%20in%20the%20desire%20for%20simpler%20structure.pdf *References:* Griffiths, T. L., & Tenenbaum, J. B. (2007). From mere coincidences to meaningful discoveries. *Cognition*, 103, 180-226. Knoblich, G., Ohlsson, S., Haider, H., & Rhenius, D. (1999). Constraint relaxation and chunk decomposition in insight problem solving. *Journal of Experimental Psychology: Learning, Memory and Cognition*, 25, 1534–1555. Neuberg, S. L., & Newsom, J. T. (1993). Personal Need for Structure: Individual Differences in the Desire for Simple Structure. *Journal of Personality and Social Psychology*, 65 (1), 113-131. Thompson, M. M., Naccarato, M. E., & Parker, K. E. (1992). Measuring cognitive needs: The development and validation of the Personal Need for Structure (PNS) and Personal Fear of Invalidity (PFI) measures. Manuscript submitted for publication.