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"Rational thinking skills were assessed using a German test battery consisting of four subtests of heuristics and biases tasks." "Cognitive Reflection was assessed using three items of the original CRT..." "Resistance to Belief Bias was assessed using five items created by Markovits and Nantel (1989) and one new item." "Resistance to Ratio Bias was assessed using four items by Toplak et al. (2014). In each item, the subjects’ task is to choose between a small and a large tray of white and black marbles...." "Disjunctive Reasoning was assessed using the knights and knaves problem (Toplak & Stanovich, 2002; adapted from Shafir, 1994) and five new items. In all items, the participants’ task was to decide whether the question can be answered with yes, no, or not at all based on the given information."

"Prior to analyses, data were cleaned and checked for outliers. Responses to items of rational thinking skills that were unusually fast (3 SD or more below the item-specific log mean; following recommendations of Ratcliff, 1993) were considered unreliable and were deleted. This applied to 0.27% of all trials at t1 and 0.19% of all trials at t2. For continuous variables (fluid intelligence, rational thinking dispositions, rational thinking skills, student satisfaction), scores deviating more than 3 SD from the sample mean were excluded from path and regression analyses." "our sample size" was "101, excluding missing values and outliers)"

"Regarding rational thinking skills, there were no significant differences between t1 and t2 in the means of cognitive reflection (t(119) = 1.73, p =.086, d = 0.16; all means are depicted in Table 1), resistance to belief bias (t(123) = 0.53, p =.598, d = 0.05), resistance to ratio bias (t(123) = −0.64, p =.521, d = −0.06), and disjunctive reasoning (t(119) = −0.31, p =.756, d = −0.03). Regarding rational thinking dispositions, there was no significant difference in consideration of future consequences between t1 and t2 (t(123) = 0.85, p =.395, d = 0.08). Interestingly, the mean scores of students’ need for cognition slightly, but significantly, declined from t1 to t2 (t(123) = −2.07, p =.040, d = −0.19). Overall, these results suggest that the students’ rational thinking skills and dispositions remained very stable over the course of two semesters in terms of both their absolute level and their relative ranking."