The article presents the results of two studies concerning the development of postformal reasoning as proposed by G. Lavouvie-Vief, with the use of the everyday problem solving dilemmas taken from the research conducted by R.A. Sebby and D.R. Papini in the Polish adaptation by E. Gurba. Study no. 1 tested the levels of reasoning in 3 age groups: early, middle, and late adulthood, providing the participants with a choice of readymade answers. Study no. 2 tested the levels of reasoning amongst the participants while using a modified version of the test which required giving an answer to an open question pertaining to the solution of a dilemma. Regardless of their age, the participants revealed a lower level of postformal reasoning in Study no. 2. Differences in the influence of spurious variables (sex, level of education) on the presented level of reasoning in the respective Studies were also observed. The discussion attempts to explain the observed differences with relation to the cognitive requirements of both methods of study as well as the form and content of the applied dilemmas