Economic views held by the general public tend to differ significantly from those of economic experts. Would these differences fade away if people were exposed to some economic instruction? In this article, the authors identify college students' preconceptions about economic issues at the beginning of the semester, verify their persistence throughout the semester, and test whether their beliefs are correlated to course performance. The authors conduct a survey at the beginning and end of the semester on a sample of first-year students taking an economic principles course. They find evidence of preconception persistence and reasoning inconsistencies, pointing to some cognitive biases as a plausible cause. Most students do not integrate the newly learned tools into their thinking process, even if they perform well in tests.